Left ventricular myocardial mass index: normal, increase. Myocardial mass: essence, norm, calculation and index, as indicated by Deciphering the results of an ultrasound examination of the heart

The average value of the mass index of the left ventricular myocardium is 71 g/m2 in men and 62 g/m2 in women. Upper bound this index is 94 and 89 g/m2, respectively.

The causes and mechanism of changes in the mass of the left ventricle in various diseases are still poorly understood.

Myocardial hypertrophy is a fundamental mechanism for the adaptation of the heart muscle to increased loads that occur both in cardiovascular diseases and during physical exertion. The heart muscle, like any muscle, thickens with an increased load on it.

The blood vessels that feed this organ do not keep up with its growth, so starvation of the heart tissues occurs and develops various diseases. With myocardial hypertrophy, problems also arise in the conduction system of the heart, as a result of which zones of abnormal activity appear in it and arrhythmias appear.

The best method for studying the anatomy of the heart and its function is echocardiography. In terms of sensitivity to cardiac hypertrophy, this method is superior to ECG. It is also possible to detect myocardial hypertrophy with the help of ultrasound of the heart.

Formula

The mass of the myocardium of the left ventricle (calculation) is determined by the following formula:

IVS - value (in cm) equal to the thickness of the interventricular septum in diastole;
KDR - a value equal to the end-diastolic size of the left ventricle;
ZLVZH - a value (in cm) equal to the thickness of the posterior wall of the left ventricle in diastole.

MI - myocardial mass index is determined by the formula:

MI=M/H2.7 or MI=M/S where

M is the mass of the myocardium of the left ventricle (in g);
H - height (in m);
S is the surface area of the body (in m2).

Causes

Causes of left ventricular hypertrophy include:

arterial hypertension;
various heart defects;
cardiomyopathy and cardiomegaly.

The mass of the myocardium of the left ventricle in 90% of patients with arterial hypertension exceeds the norm. Often hypertrophy develops with insufficiency mitral valve or with aortic defects.

The reasons why myocardial mass may exceed the norm are divided into:

Scientists have found that the presence or absence of several fragments in human DNA can contribute to cardiac hypertrophy. Of the biochemical factors leading to myocardial hypertrophy, an excess of norepinephrine and angiotensin can be distinguished. Demographic factors in the development of cardiac hypertrophy include race, age, gender, physical activity, a tendency to obesity and alcoholism, and salt sensitivity. For example, in men, myocardial mass is higher than normal more often than in women. In addition, the number of people with a hypertrophied heart increases with age.

Stages and symptoms

In the process of increasing the mass of the myocardium, three stages are distinguished:

compensation period;
subcompensation period;
decompensation period.

Symptoms of left ventricular hypertrophy begin to manifest themselves significantly only at the stage of decompensation. With decompensation, the patient is concerned about shortness of breath, fatigue, palpitations, drowsiness and other symptoms of heart failure. Specific signs of myocardial hypertrophy include dry cough and swelling of the face, which appear in the middle of the day or in the evening.

Consequences of left ventricular myocardial hypertrophy

Increased arterial pressure not only worsens well-being, but also provokes the onset of pathological processes that affect target organs, including the heart: arterial hypertension left ventricular hypertrophy occurs. This is due to an increase in the content of collagen in the myocardium and its fibrosis. An increase in myocardial mass entails an increase in myocardial oxygen demand. Which, in turn, leads to ischemia, arrhythmia and dysfunction of the heart.

Cardiac hypertrophy (increased mass of the myocardium of the left ventricle) increases the risk of developing cardiovascular diseases and can lead to premature death.

However, myocardial hypertrophy is not a death sentence: people with a hypertrophied heart can live for decades. It is simply necessary to control blood pressure and regularly undergo an ultrasound of the heart in order to track hypertrophy over time.

Treatment

The method of treating left ventricular myocardial hypertrophy depends on the cause that caused the development of this pathology. If necessary, surgery may be prescribed.

Heart surgery for myocardial hypertrophy can be aimed at eliminating ischemia - stenting coronary arteries and angioplasty. With myocardial hypertrophy due to heart disease, if necessary, prosthetic valves or dissection of adhesions are performed.

Slowing down the processes of hypertrophy (if it is caused by a sedentary lifestyle) can in some cases be achieved by using moderate physical activity, such as swimming or running. The cause of left ventricular myocardial hypertrophy may be obesity: normalization of weight during the transition to a balanced diet will reduce the load on the heart. If hypertrophy is caused by increased loads (for example, during professional sports), then they should be gradually reduced to an acceptable level.

Medicines prescribed by doctors for left ventricular hypertrophy are aimed at improving myocardial nutrition and normalizing heart rhythm. In the treatment of myocardial hypertrophy, one should stop smoking (nicotine reduces the supply of oxygen to the heart) and drinking alcohol (many medicines used for myocardial hypertrophy are not compatible with alcohol).

Calculation of myocardial mass

Left ventricular myocardial hypertrophy (LVH), as an element of its structural restructuring, is considered a sign of morphological deviation from the norm, a clear predictor of an unfavorable prognosis of the disease that caused it, as well as a criterion that determines the choice of active treatment tactics. Over the past twenty years, there have been clinical researches, who proved the independent contribution of drug-induced reduction in LV myocardial mass (LVML) in patients arterial hypertension(AH), which makes it necessary to determine and control LVMM. Based on these ideas, recent recommendations on the diagnosis and treatment of hypertension include the measurement of LVML in the algorithm of antihypertensive management of patients in order to determine the presence of LVH.

But still, there is no unambiguous idea of the pathogenicity of LVH, which is associated with interrelated problems of both methodological and methodological order: The first relate to the reliability of methods for determining LVML, the second - to evaluate the results obtained from the point of view of the presence or absence of LVH. In addition, there are numerous instrumental approaches to the determination of LVMM.

When measuring LVML, researchers are faced with multifactorial factors that have an impact on it. This is both the dependence of LVML on body size, and the possibility of only an adaptive increase in LVML, for example, with physical activity. There are also different sensitivity of instrumental methods for determining LVMM: some authors tend to have a higher sensitivity of MRI measurement.

All Echo-kg calculations of LVML based on determining the difference in LV volumes across the epicardium and endocardium, multiplied by myocardial density, face problems in determining tissue interfaces and evaluating the shape of the left ventricle. At the same time, many methods are based on linear measurements in the M-mode under the control of the B-mode, or directly in a two-dimensional image. The previously existing problem of identifying tissue interfaces, such as "pericardium-epicardium" and "blood-endocardium", in recent years, in general, has been resolved, but requires a critical attitude to studies of past years and does not relieve researchers from the need to use all the technical capabilities of US -scanners.

Individual differences in LV geometry prevent the creation of its universal mathematical model even in the absence of local violations of the LV structure and the approximation of its shape to an ellipse, which gave rise to a large number of formulas, and, consequently, criteria for determining LVH, which results in different conclusions about the presence of hypertrophy in one and the same patient.

In addition, several calculation formulas for determining LVML are currently used. The formulas recommended by the American Society of Echocardiography (ASE) and Penn Convention (PC) are more commonly used, using three measured parameters: the thickness of the myocardium of the interventricular septum (IVS), the posterior LV wall (PLV) at the end of diastole and its end-diastolic size (EDD) with inclusion (ASE formula) or not inclusion of endocardial thickness (PC formula) in the diameter of the left ventricle, depending on the formula used. But the results obtained when applying these formulas are not always comparable, therefore, to interpret the data obtained, it is necessary to clarify the method used to calculate the parameters of the left ventricle, which in practice is not always available or is neglected. The reason for the discrepancy lies in the following. The cubic formula originally recommended by ASE was suggested by B.L. Troy et al. in 1972 (LVML, gr = [(EDV+IVL+ZLV) 3 -EKD 3 ]×1.05) and then modified using the R.B. regression equation. Devereux and Reichek in 1977 (Penn Convention formula) by analyzing the relationship between echocardiographic LVML and post-mortem LV anatomical mass in 34 adults (r=0.96, p<0,001) (ММЛЖ, гр = 1,04×[(КДР+МЖП+ЗСЛЖ) 3 -КДР 3 ]-13,6) .

The discrepancies in the values of the calculated LVML obtained using these two formulas (the cubic one proposed by B.L. Troy and the PC formula) were within 20% and in 1986 R.B. Devereux, D.R. Alonso at.all. based on autopsy, 52 patients proposed an adjusted equation (LVML, r = 0.8×+0.6 - ASE formula). LVML determined by the PC formula closely correlated with LVML at autopsy (r=0.92; p<0,001), переоценивала наличие ГЛЖ лишь на 6%, а чувствительность у пациентов с ГЛЖ (масса миокарда при аутопсии >215 gr.) was 100% with a specificity of 86% (in 29 of 34 patients). The cubic formula similarly correlated with LVML at autopsy (r=0.90; p<0,001), но систематически переоценивала наличие ГЛЖ (в среднем на 25%), что было устранено введением скорректированного уравнения (формула ASE): ММЛЖ=0,8×(ММЛЖ-кубическая формула)+0,6 гр. Однако, при её использовании наблюдалась недооценка ММЛЖ при аутопсии в пределах 30% .

Less popular, but sometimes used, is the Teicholz formula (LVML = 1.05 × ((7 × (RDR + TZSLZh + TMZhP) 3) / 2.4 + KDR + TZSLZh + TMZhP) - ((7 × KDR 3) / (2 ,4+KDR))) . According to L. Teicholz, LVMM is the norm<150 гр,гр - умеренной, а >200 gr - pronounced LVH. However, these parameters can only be guidelines when using the Teicholz formula and, in addition, they do not take into account the ratio of LVML to body size.

Virtual calculation of LVML using the above three formulas with a stable value of one of the parameters (either the sum of the thickness of the IVS and RSLV, or CDR) and an increase in the other (either CDR, or the sum of the thickness of the IVS and RSLV, respectively) by a stable arbitrary value, showed different sensitivity of the formulas to changing linear indicator. It turned out that the ASE formula is more sensitive to an increase in the thickness of the myocardial walls, the Teicholz formula is more sensitive to an increase in the LV cavity, and the PC formula parity takes into account changes in the linear dimensions and thickness of the myocardium and the cavity. Thus, it is better to evaluate LVML by changing the thickness of the myocardium using more sensitive formulas in this respect - ASE and PC.

The second problem, in addition to the definition of LVML, is the lack of unified criteria for its indexation, and, consequently, the formation of LVH criteria. Determining the size of organs through their allometric dependencies on body weight, adopted in comparative morphology, is unacceptable in the human population due to the variability of the body weight of an individual, which depends on many factors, in particular on constitutional features, physical development, and also a possible change in the size of an organ as a result of a disease. .

The presence of a direct dependence of LVML on body size requires its indexation. In this regard, the mass index of the left ventricular myocardium (LVMI) is more often calculated with standardization to the body surface area (BSA). There are several more ways to calculate the myocardial mass index: by height, height 2.0, height 2.13, height 2.7, height 3.0; correction using a regression model of LVML depending on age, body mass index and BSA.

Past studies prove the influence of various factors on myocardial mass in different age groups. So, in early childhood, the weight of the LV myocardium is mainly determined by the number of cardiomyocytes (CMC), which reach a maximum number during the first year of life, in the future, the growth of the LV depends on the increase in the size of the CMC (physiological hypertrophy) and this physiological process is influenced by many factors - body size, blood pressure, blood volume, genetic factors, salt intake, blood viscosity, which determine the phenotypic increase in LV mass. After puberty, other factors already determine the degree of physiological hypertrophy, while in adults there is a relationship between LVMH and age. The effect of height on LVML variability was studied by de G. Simone et al. and in 1995 on 611 normotensive individuals with normal body weight aged 4 months to 70 years (including 383 children and 228 adult patients). LVMH was normalized to body weight, height, BSA. Height-indexed 2.7 LVML increased with height and age in children, but not in adults, suggesting an influence of other variables on adult LV mass.

Thus, the influence of various factors on the variability of LVML in children and adults does not allow the use of the same approaches to the assessment and diagnosis of LVLV. At the same time, indexation to a height of 2.7 is more justified in children than in adults, who may have an overestimation of this criterion.

The correction of LVML to BSA, calculated according to the Du Bois formula, is more often used, but this standardization is imperfect, because it underestimates LVML in people with obesity.

Analyzing data from the Framingham Heart Study and using the Penn Convention formula for growth indexing D. Levy, R.J. Garrison, D.D. Savage et al. LVH was defined as the deviation of LVML values from the mean ± 2SD in the control group, i.e. 143 gr/m for men and 102 gr/m for women. Over four years of follow-up, cardiovascular morbidity (CVD) was higher in individuals with larger LVMI: in men with LVMI<90 гр/м она составила 4,7% против 12,2% при ИММЛЖ ≥140 гр/м, у женщин - 4,1% и 16,1% соответственно . Наблюдался рост ССЗ при более высокой ММЛЖ у мужчин в 2,6, а у женщин - в 3,9 раза, что доказывает прогностическую значимость и важность правильной оценки массы миокарда, поиска более точных диагностических критериев ГМЛЖ для раннего её выявления.

In the domestic DAH-1 recommendations, the criterion for diagnosing LVMH is the highest level of the norm - the value of LVMI is more than 110 g/m 2 in women and 134 g/m 2 in men, although a value of more than 125 g is prognostically unfavorable in men with arterial hypertension (AH) / m 2.

The frequency of detection of LVMH in both obesity and CVD increases with indexation to growth (growth 2.7), however, there are not enough data yet to judge the additional prognostic value of this approach.

Comparison of different LVML indexes for mortality risk prediction was studied by Y. Liao, R.S. Cooper, R. Durazo-Arvizu et al. (1997) in 998 patients with cardiac pathology during a 7-year follow-up. A high correlation between different indexations was found (r=0.90-0.99). At the same time, an increase in any of the indices was associated with a threefold risk of death from all causes and heart disease. 12% of individuals with LVMH based on height indexing had a moderate increase in LVML with no increase in risk, although overweight was common in this group, suggesting that indexing for height was justified in the presence of obesity. Thus, myocardial hypertrophy detected using different indexing equally retains its prognostic value in relation to the risk of death.

P. Gosse, V. Jullien, P. Jarnier et al. studied the relationship between LVMI and mean daily systolic blood pressure (SBP) according to 24-hour blood pressure monitoring (ABPM) in 363 untreated hypertensive patients with antihypertensive drugs. LVM indexation was carried out according to BSA, height, height 2.7, and the data obtained were analyzed taking into account gender. LVMH corresponding to SBP >135 mm Hg. Art., was considered as a criterion for LVMH. A higher percentage of LVH detection was found during indexation of LVML by growth of 2.7 (50.4%) and growth (50.1%), and LVH detection during indexation by BSA was 48.2% due to its decrease in obese individuals, therefore scientists conclude that the LVMH criterion is more sensitive when indexed by height 2.7 and suggest that cut-off points be considered a value exceeding 47 g/m 2.7 in women and 53 g/m 2.7 in men.

The above ambiguous ideas about the normal values of LVMI, LVMI and LVH criteria are presented in Table 1.

LVMI as a criterion for LVLV with and without gender

D. Levy, Framingham Research, 1987

J.K. Galy, 1992

I.W. Hammond, 1986

E.Aberget, 1995

De G. Simone, 1994

Recommendations for chamber quantification: Guidelines, 2005

Not gender sensitive

M.J. Koren, 1981

De G. Simone, 1995

A large range of scatter of LVMI standards within one indexation is obvious, and, consequently, there is uncertainty in the conclusions about the presence of myocardial hypertrophy. Indexing of LVMI according to PPT gives a range of criteria from 116 to 150 g/m 2 in men games/m 2 in women; indexation to growth 2.0 for men games/m 2.7 for women; indexation to height - 77, for men and 69, g/m. Therefore, it is impossible to confidently judge the presence or absence of LVMH when the value of LVMI falls within the range of scatter of normal criteria. In addition, it is important that a large proportion of patients with mild or moderate LVMH, which is characteristic of a large group of people with mild hypertension, will fall into this indefinite interval.

The definition of LVML is also important for characterizing a disproportionately high LVML (LVMML), since the absolute values of the actual mass are included in the formula for calculating the disproportionality coefficient that determines the presence and severity of LVMLZh. An increase in LVML to a greater extent than required by the hemodynamic load was found in individuals both with and without LVH and was associated with an increased risk of cardiovascular complications, regardless of the presence of LVH.

So, despite the 30-year use of Echo-kg as a criterion for determining LVMH, there remains inconsistency in various studies, there is no presentation of a universal standardization method, although each of the listed criteria is based on fairly large studies, some of which are supported by autopsy data. The optimal way to normalize LV mass remains controversial, and the use of different indexing causes confusion in threshold values, disorients the work of scientists and practitioners in choosing the best indexing and interpretation of the results, while maintaining the relevance of choosing a method for calculating LVMI. The controversy of examination methods was also stated by other authors, who believe that studies of large population cohorts are needed to compare heart sizes measured by different methods, develop more accurate standards, select the best indexing methods, and identify factors that affect LVM, many of which remain undisclosed.

It is possible that before searching for optimal algorithms for determining LVMI and its standardization in AH, one should clarify which of the above methods is the most comparable with the others in assessing LVH. Our discriminant analysis for this purpose, in which the group formation criterion was one of the methods for diagnosing LVH, and all other methods together were predictors, revealed that such a technique is the PC formula with standardization according to BSA (Table 2).

Correspondence of the incidence of LVH according to different methods of its determination

(performance ratio (KFR) in %; p<0,001)

All methods except dependent

Note: PCppt, PCgrowth, PCgrowth 2.7 - PC formula, indexation to PPT, growth and growth 2.7, respectively; ASEppt, ASEgrowth, ASEgrowth 2.7 - ASE formula, indexation to PPT, growth and growth 2.7, respectively.

On the other hand, the greatest predictor value for LVH (CFR=95.7%), revealed by discriminant analysis, of the combination of ABPM, integral structural and functional parameters of the left ventricle and a number of regulatory peptides only in the case of using the MS technique with standardization to BSA also testified in favor of its greatest adequacy for the diagnosis of LVH.

Onishchenko Alexander Leonidovich, Doctor of Medical Sciences, Professor, Vice-Rector for Research, SBEI DPO NGIUV MOH of Russia, Novokuznetsk;

Filimonov Sergey Nikolaevich, Doctor of Medical Sciences, Professor, Vice-Rector for Academic Affairs of the State Budgetary Educational Institution of Education and Science of the NGIUV of the Ministry of Health of Russia, Novokuznetsk.

Bibliographic link

URL: http://science-education.ru/ru/article/view?id=23603 (accessed 03/11/2018).

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Myocardial mass: essence, norm, calculation and index, as it says

What is myocardial mass and how to estimate it correctly? This question is most often asked by patients who have undergone echocardiography and found, among other parameters, heart muscle mass and mass index.

Myocardial mass is the weight of the heart muscle, expressed in grams and calculated from ultrasound data. This value characterizes many pathological processes, and its change, usually upward, may indicate an unfavorable prognosis for the course of the pathology and an increased risk of serious complications.

The increase in myocardial mass is based on hypertrophy, that is, thickening, which characterizes the structural restructuring in the heart muscle, which forces doctors not only to conduct dynamic monitoring, but also to switch to active treatment tactics.

Modern recommendations regarding the therapy and diagnosis of various pathologies of the heart indicate that the mass of the myocardium of the left ventricle (LV) is not only possible, but also necessary to control, and for this, periodic ultrasound examinations of the heart are included in the protocols for managing patients with a risk of cardiac hypertrophy.

The norm of myocardial mass for men, on average, is considered to be in the range of r, for women - r.

The correct interpretation of echocardiography indicators still remains a serious problem, because it is necessary to correlate the instrumentally obtained data with a specific patient and establish whether there is already hypertrophy or some deviation from the norm can be considered a physiological feature.

To a certain extent, the mass of the myocardium can be considered a subjective indicator, because the same result for people of different heights, weights and genders can be regarded differently. For example, an indicator of myocardial mass in a large man involved in weightlifting will normally be excessive for a fragile girl of short stature who is not fond of going to the gym.

It has been established that the mass of the myocardium has a close relationship with the size of the body of the subject and the level of physical activity, which must be taken into account when interpreting the results, especially if the indicator is very slightly different from the norm.

Reasons for the deviation of the mass and mass index of the heart from normal numbers

The mass of the myocardium is increased in pathological processes leading to its overload:

An increase in the mass of muscle tissue also occurs normally - with enhanced physical training, when intense sports cause an increase not only in skeletal muscles, but also in the myocardium, which provides the organs and tissues of the trainee with oxygen-rich blood.

Athletes, however, run the risk of eventually moving into the category of people with myocardial hypertrophy, which under certain conditions can become pathological. When the thickness of the heart muscle becomes greater than the coronary arteries can supply blood, there is a risk of heart failure. It is with this phenomenon that sudden death in well-trained and apparently quite healthy people is most often associated.

Thus, an increase in myocardial mass, as a rule, indicates a high load on the heart, whether during sports training or pathological conditions, but regardless of the cause, cardiac muscle hypertrophy deserves close attention.

Methods for calculating myocardial mass and mass index

Myocardial mass and its index are calculated based on echocardiography data in different modes, while the doctor must use all the possibilities of instrumental examination, correlating two- and three-dimensional images with Doppler data and using additional capabilities of ultrasound scanners.

Since, from a practical point of view, the large mass of the left ventricle, as the most functionally loaded and prone to hypertrophy, plays the greatest role, the calculation of the mass and mass index for this particular chamber of the heart will be discussed below.

The calculation of the myocardial mass index and the actual mass in different years was carried out using a variety of formulas due to the individual features of the geometry of the heart chambers in the subjects, which make it difficult to create a standard calculation system. On the other hand, a large number of formulas complicated the formulation of the criteria for hypertrophy of a particular part of the heart, so the conclusions regarding its presence in the same patient could differ with different methods of assessing EchoCG data.

Today, the situation has improved somewhat, largely due to more modern ultrasound diagnostic devices, which allow only minor errors, but there are still several calculation formulas for determining the mass of the myocardium of the left ventricle (LV). The most accurate of them are the two proposed by the American Society of Echocardiography (ASE) and the Penn Convention (PC), which take into account:

The thickness of the heart muscle in the septum between the ventricles;
The thickness of the posterior LV wall at the end of the period of filling with blood and before the next contraction;
End-diastolic size (EDD) of the left ventricle.

In the first formula (ASE), the thickness of the left ventricle includes the thickness of the endocardium, in the second similar calculation system (PC) it is not taken into account, so the formula used must be indicated as a result of the study, since the interpretation of the data may be erroneous.

Both calculation formulas are not distinguished by absolute reliability and the results obtained from them often differ from those at the autopsy, however, of all the proposed ones, they are the most accurate.

The formula for determining the mass of the myocardium looks like this:

0.8 x (1.04 x (IVS + CDR + ZSLZh) x 3 - KDR x 3) + 0.6, where IVS is the width of the interventricular septum in centimeters, CDR is the end-diastolic size, ZSLZh is the thickness of the posterior LV wall in centimeters.

The norm of this indicator differs depending on gender. Among men, the range d will be normal, for women - r.

The myocardial mass index is a value that takes into account the height and weight parameters of the patient, correlating the mass of the myocardium to the body surface area or height. It is worth noting that the mass index, which takes into account growth, is more applicable in pediatric practice. In adults, growth is constant and therefore does not have such an impact on the calculation of the parameters of the heart muscle, and possibly even leads to erroneous conclusions.

The mass index is calculated as follows:

IM=M/H2.7 or M/P, where M is the muscle mass in grams, P is the height of the subject, P is the body surface area, m2.

Domestic experts adhere to a single accepted figure for the maximum mass index of the left ventricular myocardium - 110 g/m2 for women and 134 g/m2 for the male population. With diagnosed hypertension, this parameter is reduced in men to 125. If the index exceeds the specified maximum allowable values, then we are talking about the presence of hypertrophy.

The form of an echocardiographic study usually indicates lower average standards for the mass index relative to the body surface: g / m2 in men and g / m2 in women (different formulas are used, therefore, the indicators may differ). These limits characterize the norm.

If the mass of the myocardium is correlated with the length and area of the body, then the range of variation in the norm of the indicator will be quite high: for men and women when taking into account body area, for men and women when indexed by height.

Given the above-described features of the calculations and the resulting figures, left ventricular hypertrophy cannot be accurately excluded, even if the mass index falls within the range of normal values. Moreover, many people have a normal index, while they have already established the presence of initial or moderately severe cardiac hypertrophy.

Thus, the mass of the myocardium and the mass index are parameters that make it possible to judge the risk or presence of hypertrophy of the heart muscle. Interpretation of the results of echocardiography is a difficult task, which is within the power of a specialist with sufficient knowledge in the field of functional diagnostics. In this regard, independent conclusions of patients are far from always correct, therefore, it is better to go to a doctor to decipher the result in order to exclude false conclusions.

Calculation of myocardial mass

Cardiovascular diseases are the leading cause of death in Russia. Persons suffering from them should be registered with a cardiologist. Myocardial mass index is an objective numerical indicator that characterizes the work of the heart. It allows you to identify the disease in time and start treatment. How to calculate myocardial mass index, and what does it mean?

Reasons for deviations

The heart is a muscle that works like a pump. Its main task is to pump blood. The mass of the heart depends on the volume of blood pumped. The child has a small heart - the capacity of the vascular bed is small, so there is little work for the heart. An adult large man has a larger heart than a fragile girl, the reason for this is a different volume of blood. A weightlifter and an office worker have hearts of different weights. A weightlifter needs a big heart, as his muscles consume more oxygen.

The mass of the heart of a healthy person depends on several factors and ranges from 270-380 grams in men, in women 203-302.

Demographic factors in the development of cardiac hypertrophy include race, age, gender, physical activity, obesity, and alcoholism.

Deviation from these indicators is an alarm signal. The reason may be:

hypertension;
ischemic disease;
congenital or acquired heart defects;
obesity;
great physical activity;
bad habits.

An increase in the mass of the heart muscle also occurs in healthy people - professional athletes. Athletes with age can move into a risk group for developing cardiovascular diseases. Their coronary arteries cease to supply the hypertrophied muscle with a sufficient volume of blood, and coronary disease will occur against this background.

It is possible to assume hypertrophy according to clinical data: shortness of breath, fatigue. Electrocardiography reveals characteristic changes. It is possible to diagnose pathology and give an accurate quantitative assessment of the detected changes in myocardial hypertrophy using echocardiography, ultrasound (ultrasound).

Research methods

Acoustic waves that are not perceived by the human ear are called ultrasound. Devices - ultrasonic scanners, generate and receive ultrasound. During the study, when passing through the tissues of the body, at the interface between two media, part of the waves is reflected, forming an image on the screen of the apparatus. In medicine, ultrasound is used to examine patients with diseases of the internal organs.

With echocardiography, the mass index of the myocardium of the left ventricle is calculated

Ultrasound examination of the heart allows you to determine:

myocardial wall thickness;
thickness of intracardiac partitions;
cavity sizes;
blood pressure value;
valve condition.

These data are used to calculate the mass of the myocardium.

The introduction of echocardiography into clinical practice has significantly improved the diagnosis of cardiac pathologies. Myocardial hypertrophy can be local - in one part of the heart. In this case, deformations occur, the operation of the valves is disrupted, and stenosis of the aortic mouth develops.

Additional methods of echocardiography: transesophageal, stress echocardiography, significantly expanded the possibilities of diagnosing.

Payment

The calculation is performed on the basis of ultrasound data in different modes, using all the parameters of ultrasonic devices. Of practical importance is the mass of the myocardium of the left ventricle, which performs the greatest amount of work. Until recently, the calculation was carried out using different methods, which complicated the work of cardiologists due to the lack of uniform criteria.

The mass of the myocardium of the left ventricle in 90% of patients with arterial hypertension exceeds the norm

the size of the interventricular septum;
the volume of the left ventricle;
back wall thickness.

The mass of the myocardium of the left ventricle is calculated by the formula:

0.8 x +0.6, where:

IVS - the size of the interventricular septum;
KDR - the volume of the left ventricle;
ZLVZh - the thickness of the posterior wall of the left ventricle.

Among men, the mass of the myocardium is normal - 135-180 g, in women 95-142.

In addition to the problem of developing uniform criteria for evaluating ultrasound data, there is the problem of taking into account the individual characteristics of the patient. Height and weight have a big impact on the results of the study.

To account for individual parameters, there is a special index.

It is calculated according to the formula:

MI, myocardial mass index;
M is the mass of the heart muscle;
H is the patient's height;
P is the area of the body in square meters.

The first formula is applied in the field of pediatrics. The growth of children is a value that varies over a wide range. The second is for adults, where height does not significantly affect the results of calculations. The norm for adults is 136 g / m² for men, 112 g / m² for women.

If the indicators exceed these standards, then this indicates myocardial hypertrophy. Analysis of the results of an ultrasound examination is available to a highly qualified specialist. Self-assessment of ultrasound data leads to false conclusions. Every year, millions of people die from cardiovascular diseases worldwide. Advances in medicine are able to prevent most deaths, provided that this pathology is treated in a timely manner.

Ultrasound examination of the heart, an informative non-invasive method, allows you to identify myocardial hypertrophy - the result of increased heart function, an alarm signal, a harbinger of a serious, intractable disease. Include ultrasound in the list of annual preventive examinations. Especially if you are over 40.

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How is the mass of the myocardium of the left ventricle calculated at home?

The mass index of the left ventricular myocardium is a figure that determines the exact weight of the patient's heart muscle in grams, obtained by calculating the specific data taken by the ultrasound machine during the heart scanning procedure. This index characterizes some cardiac pathologies associated with structural changes in the patient's myocardium and shows the degree of their severity.

The principle of calculating the mass of the LV myocardium

The mass of the myocardium of the left ventricle has a certain norm, any deviation from which indicates a disease affecting the heart or myocardium. Often, the data deviate upwards, and there is only one reason for this phenomenon - hypertrophy of the heart muscle.

Monitoring LV mass is recommended on an ongoing basis in order to be able to prevent serious cardiac pathology in advance. This is especially true for those patients who have an increased risk of hypertrophy. The normal result of the calculation after echocardiography is the mass of the left ventricle from 135 to 182 g if the patient is a man, and from 95 to 141 g in women.

However, we note that in some cases a slightly increased mass of the heart or myocardium is considered a physiological feature of a person that does not indicate the course of the disease in his body. To determine whether hypertrophy affects the heart or not, the doctor must compare the individual physical characteristics of the patient with the obtained size and weight of his myocardium. And only after the pathological nature of hypertrophy is confirmed, the doctor can make an approximate diagnosis, which must be confirmed by a number of additional laboratory and instrumental studies.

Causes affecting the deviation of the LV mass index of the myocardium from the norm

In most cases, the left ventricle and the myocardium as a whole increase under the influence of certain pathologies that provoke their significant overload of the heart:

valve defects;
cardiomyopathy;
arterial hypertension;
myocardial dystrophy.

In some cases, the mass of the heart muscle and tissue increases without exposure to hypertrophic pathologies. For example, if a man or woman is actively involved in sports, the myocardium is enriched with oxygen more intensively, as a result of which the thickness of the walls of these organs, as well as weight, increases significantly.

However, we note that hypertrophy as a disease is considered common among athletes, because a normal increase in myocardial mass over time can become a pathological abnormality requiring medical intervention. Typically, this phenomenon is observed in cases where the thickness of the patient's heart muscle significantly exceeds the size of his coronary arteries, as a result of which the left ventricle and the whole heart cease to receive a sufficient amount of blood. The result of such a deviation is heart failure, provoking a fatal outcome.

Important! In any case, an increased mass of the myocardium indicates serious stress on the left ventricle and heart of a person, due to which their hypertrophy occurs. Therefore, even if such a deviation, at first glance, is normal, it is still recommended not to allow it.

Methods for calculating the mass of the left ventricle of the myocardium

In most cases, the determination of IMM is performed using the ECHOCG procedure, based on the results of scanning the heart and myocardium in different modes. However, for an accurate calculation of the mass of the myocardium of the left ventricle, echocardiography alone is not enough, and the doctor will definitely need an additional image of the organs, in two- and three-dimensional projection.

You can scan the myocardium and left ventricle using a doppler or a special ultrasound machine that displays the projection of the organ on the screen in natural size. Many may wonder why the mass of only one left ventricle is calculated? The answer is simple: the left ventricle, unlike the right one, is subjected to much greater loads, due to which hypertrophy occurs more often in its cavity.

The very norm of the myocardial mass index is calculated in many ways, but today medicine uses only the two most effective formulas: ASE and PC, which include the following data:

the thickness of the heart muscle between the right and left ventricles;
the thickness of the posterior cavity of the left ventricle (this indicator is measured in two stages: when the organ is completely filled with blood and when it is emptied);
end-diastolic dimensions of the left ventricle.

If the mass of the myocardium is calculated using the ASE formula, then it should be taken into account that the thickness of the heart muscle also includes the thickness of the endocardium, which is not observed when calculating using the RS formula. Therefore, the name of the formula must be indicated in the protocol when calculating, since the initial mass differs slightly for them.

So, in order to determine the mass index of the left ventricle, it is initially required to scan the heart and myocardium, and substitute the resulting sizes of these organs into the following formula:

The abbreviations in this formula have the following designations:

IVS - the width of the septum between the ventricles, expressed in cm;
EDD - LV end-diastolic size;
ZLVZh - an indicator of the thickness of the posterior cavity of the left ventricle, expressed in cm.

Depending on who the patient is (male or female), the norm of the myocardial mass index will be slightly different. This difference looks like this:

If the patient is a man, then the norm for him will be from 135 to 182 grams;
If the patient is a woman, then for her the norm ranges from 95 to 141 grams.

With an overestimated indicator, it can be assumed that hypertrophy is rapidly developing in the patient's body, requiring urgent medical intervention.

Calculation of myocardial mass depending on the weight and height of the patient

To determine the stage of development of hypertrophy at the time of its diagnosis and to understand how dangerous it is for the patient's health, the doctor compares the size and mass of the myocardium with the height and weight of the patient. However, during this procedure, certain difficulties often arise.

If the patient is a man or woman over the age of 25, then his body is already fully formed, and the heart does not change its size in the future without the influence of negative factors, such as hypertrophy. However, if the patient has not reached the aforementioned age, then his myocardium is able to change its size and mass even without any pathology, which in turn will greatly complicate diagnosis.

As for the calculation of the ratio of myocardial mass to height and body weight, it is performed strictly according to the following formula:

The abbreviation of this formula is deciphered as follows:

M is the weight of the muscle, expressed in grams;
P is the patient's height;
P - the area of the patient's body, expressed in square meters.

After calculating the above parameters and establishing a relationship between them, the doctor determines whether the LV is hypertrophied or not, at what stage of development the pathology is at the time of the examination. However, this is not enough to make an accurate diagnosis; the patient will still have to undergo a number of additional laboratory and instrumental studies.

Ultrasound of the heart is an informative and safe diagnostic method, another name for this procedure is echocardiography (EchoCG), what will this study show, what diseases does it reveal and who needs to undergo it?

The value of this diagnostic method lies in the fact that it is able to determine the pathology of the heart muscle at the earliest stages, when the patient does not yet have any symptoms of heart disease. The simplicity and safety of the method allows it to be used in children and adults.

With serious indications, it is possible to determine the pathology of the development of the heart in the fetus with the help of echocardiography even before the birth of the child.

Why is an echocardiogram performed?

Echocardiography is used to detect changes in the structure of the tissues of the heart muscle, dystrophic processes, malformations and diseases of this organ.

A similar study is carried out for pregnant women with suspected pathology of fetal development, signs of developmental delay, the presence of epilepsy in a woman, diabetes mellitus, endocrine disorders.

Indications for echocardiography may be symptoms of heart defects, suspected myocardial infarction, aortic aneurysm, inflammatory diseases, neoplasms of any etiology.

must be carried out if the following symptoms are observed:

chest pains;
weakness during physical activity and regardless of it;
cardiopalmus:
interruptions in the heart rhythm;
swelling of the hands and feet;
complications after influenza, SARS, tonsillitis, rheumatism;
arterial hypertension.

Examination can be done in the direction of a cardiologist and at your own request. There are no contraindications for its implementation. Special preparation for ultrasound of the heart is not carried out, it is enough to calm down and try to maintain a balanced state.

Specialist during the study evaluates the following parameters:

the state of the myocardium in the phase of systole and diastole (contraction and relaxation);
dimensions of the heart chambers, their structure and wall thickness;
the state of the pericardium and the presence of exudate in the heart sac;
functioning and structure of arterial and venous valves;
the presence of blood clots, neoplasms;
the presence of the consequences of infectious diseases, inflammation, heart murmurs.

The processing of the results is most often carried out using a computer program.

More details about this research technique are described in this video:

Normal values in adults and newborns

It is impossible to determine uniform standards for the normal state of the heart muscle for men and women, for adults and children of different ages, for young and elderly patients. The figures below are averages, there may be small differences in each case..

The aortic valve in adults should open by 1.5 or more centimeters, the opening area of the mitral valve in adults is 4 sq. cm. The volume of exudate (liquid) in the heart sac should not exceed 30 sq. ml.

Deviations from the norm and principles for decoding the results

As a result of echocardiography, it is possible to detect such pathologies of the development and functioning of the heart muscle and related diseases:

heart failure;
slowing, acceleration or interruptions in the heart rate (tachycardia, bradycardia);
pre-infarction state, myocardial infarction;
arterial hypertension;
vegetative-vascular dystonia;
inflammatory diseases: cardiac myocarditis, endocarditis, exudative or constrictive pericarditis;
cardiomyopathy;
signs of angina;
heart defects.

The examination protocol is filled in by a specialist conducting an ultrasound of the heart. The parameters of the functioning of the heart muscle in this document are indicated in two values - the norm and the parameters of the subject. The protocol may contain abbreviations that are incomprehensible to the patient:

MLVZH- mass of the left ventricle;
LVMI is the mass index;
KDR- final diastolic size;
BEFORE- long axis;
KO– short axis;
LP- left atrium
PP- right atrium;
FV is the ejection fraction;
MK- mitral valve;
AK- aortic valve;
DM- movement of the myocardium;
DR- diastolic size;
UO- stroke volume (the amount of blood that is ejected by the left ventricle in one contraction);
TMMZhPd- the thickness of the myocardium of the interventricular septum in the diastole phase;
TMMPs- the same, in the systole phase.

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Literature

Left ventricular myocardial hypertrophy (LVH), as an element of its structural restructuring, is considered a sign of a morphological deviation from the norm, a clear predictor of an unfavorable prognosis of the disease that caused it , as well as the criterion that determines the choice of active treatment tactics.

Over the past twenty years, clinical studies have been conducted that have proven the independent contribution of drug-induced reduction in LV myocardial mass (LVML) in patients with arterial hypertension (AH), which makes it necessary to determine and control LVML. Based on these ideas, recent recommendations on the diagnosis and treatment of hypertension include the measurement of LVML in the algorithm of antihypertensive management of patients in order to determine the presence of LVH.

But still, there is no unambiguous idea of the pathogenicity of LVH, which is associated with interrelated problems of both methodological and methodological order: The first relate to the reliability of the methods for determining LVML, the second - to evaluate the results obtained from the point of view of the presence or absence of LVH. In addition, there are numerous instrumental approaches to the determination of LVMM.

When measuring LVML, researchers are faced with multifactorial factors that have an impact on it. This is both the dependence of LVML on body size, and the possibility of only an adaptive increase in LVML, for example, during physical activity. There are also different sensitivity of instrumental methods for determining LVMM: some authors tend to have a higher sensitivity of MRI measurement.

and many methods are based on linear measurements in M-mode under control of B-mode, or directly in a two-dimensional image. The previously existing problem of identifying tissue interfaces, such as "pericardium-epicardium" and "blood-endocardium", in recent years, in general, has been resolved, but requires a critical attitude to studies of past years and does not relieve researchers from the need to use all the technical capabilities of US -scanners.

the results obtained when applying these formulas are not always comparable, therefore, to interpret the data obtained, it is necessary to clarify the method used to calculate the parameters of the left ventricle, which in practice is not always available or is neglected. The reason for the discrepancy lies in the following. The cubic formula originally recommended by ASE was suggested by B.L. Troy et al. in 1972 (LVML, gr = [(EDV+IVL+ZLV) 3 -EKD 3 ]×1.05) and then modified using the R.B. regression equation. Devereux and Reichek in 1977 (Penn Convention formula) by analyzing the relationship between echocardiographic LVML and post-mortem LV anatomical mass in 34 adults (r=0.96, p<0,001) (ММЛЖ, гр = 1,04×[(КДР+МЖП+ЗСЛЖ) 3 -КДР 3 ]-13,6) .

The discrepancies in the values of the calculated LVML obtained using these two formulas (the cubic one proposed by B.L. Troy and the PC formula) were within 20% and in 1986 R.B. Devereux, D.R. Alonso at.all. Based on the autopsy of 52 patients, an adjusted equation was proposed (LVML, gr = 0.8×(1.04×[(ER+IVL+ZLV) 3 -ER 3 ])+0.6 - ASE formula). LVML determined by the PC formula closely correlated with LVML at autopsy (r=0.92; p<0,001), переоценивала наличие ГЛЖ лишь на 6%, а чувствительность у пациентов с ГЛЖ (масса миокарда при аутопсии >215 gr.) was 100% with a specificity of 86% (in 29 of 34 patients). The cubic formula similarly correlated with LVML at autopsy (r=0.90; p<0,001), но систематически переоценивала наличие ГЛЖ (в среднем на 25%), что было устранено введением скорректированного уравнения (формула ASE): ММЛЖ=0,8×(ММЛЖ-кубическая формула)+0,6 гр. Однако, при её использовании наблюдалась недооценка ММЛЖ при аутопсии в пределах 30% .

Less popular, but sometimes used, is the Teicholz formula (LVML = 1.05 × ((7 × (RDR + TZSLZh + TMZhP) 3) / 2.4 + KDR + TZSLZh + TMZhP) - ((7 × KDR 3) / (2 ,4+KDR))) . According to L. Teicholz, LVMM is the norm<150 гр, 150-199 гр — умеренной, а >200 gr - pronounced LVH. However, these parameters can only be guidelines when using the Teicholz formula and, in addition, they do not take into account the ratio of LVML to body size.

Virtual calculation of LVML using the above three formulas with a stable value of one of the parameters (either the sum of the thickness of the IVS and RSLV, or CDR) and an increase in the other (either CDR, or the sum of the thickness of the IVS and RSLV, respectively) by a stable arbitrary value, showed different sensitivity of the formulas to changing linear indicator. It turned out that the ASE formula is more sensitive to an increase in the thickness of the myocardial walls, the Teicholz formula is more sensitive to an increase in the LV cavity, and the PC formula takes into account changes in the linear dimensions and thickness of the myocardium and the cavity in parity. Thus, it is better to evaluate LVML by changing the thickness of the myocardium using more sensitive formulas in this respect - ASE and PC.

After puberty, other factors already determine the degree of physiological hypertrophy, while in adults there is a relationship between LVMH and age. The effect of height on LVML variability was studied by de G. Simone et al. and in 1995 on 611 normotensive individuals with normal body weight aged 4 months to 70 years (including 383 children and 228 adult patients). LVMH was normalized to body weight, height, BSA. Height-indexed 2.7 LVML increased with height and age in children, but not in adults, suggesting an influence of other variables on adult LV mass.

The correction of LVML to BSA, calculated according to the Du Bois formula, is more often used, but this standardization is imperfect, because it underestimates LVML in people with obesity.

Analyzing data from the Framingham Heart Study and using the Penn Convention formula for growth indexing D. Levy, R.J. Garrison, D.D. Savage et al. LVH was defined as the deviation of LVML values from the mean ± 2SD in the control group, i.e. 143 gr/m for men and 102 gr/m for women. Over four years of follow-up, cardiovascular morbidity (CVD) was higher in individuals with larger LVMI: in men with LVMI<90 гр/м она составила 4,7% против 12,2% при ИММЛЖ ≥140 гр/м, у женщин — 4,1% и 16,1% соответственно . Наблюдался рост ССЗ при более высокой ММЛЖ у мужчин в 2,6, а у женщин — в 3,9 раза, что доказывает прогностическую значимость и важность правильной оценки массы миокарда, поиска более точных диагностических критериев ГМЛЖ для раннего её выявления.

The above ambiguous ideas about the normal values of LVMI, LVMI and LVH criteria are presented in Table 1.

Table 1

LVMI as a criterion for LVLV with and without gender

Indicator	Indexing		LVMI value
Indicator	Indexing
LVMI, g/m2 LVMI, g/m		D. Levy, Framingham Research, 1987
LVMI, g/m2		J.K. Galy, 1992
LVMI, g/m2		I.W. Hammond, 1986
LVMI, g/m		E.Aberget, 1995
LVMI, g/m2
LVMI, g/m 2.7		De G. Simone, 1994
LVMI, g/m 2.7		J.J. Mahn, 2014
LVMI, g/m2 LVMI, g/m LVMI, g/m 2.7		Recommendations for chamber quantification: Guidelines, 2005
Not gender sensitive
LVMI, g/m2		M.J. Koren, 1981
LVMI, g/m 2.7		De G. Simone, 1995

A large range of scatter of LVMI standards within one indexation is obvious, and, consequently, there is uncertainty in the conclusions about the presence of myocardial hypertrophy. Indexing of LVML according to BSA gives a range of criteria from 116 to 150 g/m 2 in men and 96 - 120 g/m 2 in women; indexation to height 2.7 - 48 - 50 for men and 45 - 47 g / m 2.7 for women; indexation to growth - 77.7 - 163 for men and 69.8 - 121 g / m. Therefore, it is impossible to confidently judge the presence or absence of LVMH when the value of LVMI falls within the range of scatter of normal criteria. In addition, it is important that a large proportion of patients with mild or moderate LVMH, which is characteristic of a large group of people with mild hypertension, will fall into this indefinite interval.

The definition of LVML is also important for characterizing a disproportionately high LVML (LVMML), since the absolute values of the actual mass are included in the formula for calculating the disproportionality coefficient that determines the presence and severity of LVMLZh. An increase in LVML to a greater extent than required by the hemodynamic load was found in individuals both with and without LVH and was associated with an increased risk of cardiovascular complications, regardless of the presence of LVH.

table 2

Correspondence of the incidence of LVH according to different methods of its determination

(performance ratio (KFR) in %; p<0,001)

	All methods except dependent

Note: PCppt, PCgrowth, PCgrowth 2.7 - PC formula, indexation to PPT, growth and growth 2.7, respectively; ASEppt, ASEgrowth, ASEgrowth 2.7 — ASE formula, indexation to PPT, growth and growth 2.7, respectively.

Reviewers:

Onishchenko Alexander Leonidovich, Doctor of Medical Sciences, Professor, Vice-Rector for Research, SBEI DPO NGIUV MOH of Russia, Novokuznetsk;

Bibliographic link

Zadorozhnaya M.P., Razumov V.V. DISPUTE ISSUES OF ECHOCARDIOGRAPHIC DETERMINATION OF LEFT VENTRICULAR MYOCARDIAL MASS AND ITS HYPERTROPHY (ANALYTICAL REVIEW AND OWN OBSERVATIONS) // Modern problems of science and education. - 2015. - No. 6.;
URL: https://science-education.ru/ru/article/view?id=23603 (date of access: 12/28/2017).

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What allows you to examine (EchoCG)

Ultrasound of the heart allows the doctor to determine many parameters, norms and deviations in the work of the cardiovascular system, to assess the size of the heart, the volume of the heart cavities, the thickness of the walls, the frequency of strokes, the presence or absence of blood clots and scars.

Also, this examination shows the state of the myocardium, pericardium, large vessels, mitral valve, the size and thickness of the walls of the ventricles, determines the state of valve structures and other parameters of the heart muscle.

After the examination (Echo KG), the doctor records the results of the examination in a special protocol, the decoding of which allows you to detect cardiac diseases, abnormalities, anomalies, pathologies, as well as make a diagnosis and prescribe appropriate treatment.

When to perform (Echo CG)

The sooner there are diagnosed pathologies or diseases of the heart muscle, the greater the chance of a positive prognosis after treatment. Ultrasound should be performed with such symptoms:

recurrent or frequent pain in the heart;
rhythm disturbances: arrhythmia, tachycardia;
dyspnea;
increased blood pressure;
signs of heart failure;
transferred myocardial infarction;
if there is a history of heart disease;

You can undergo this examination not only in the direction of a cardiologist, but also other doctors: endocrinologist, gynecologist, neurologist, pulmonologist.

What diseases are diagnosed by ultrasound of the heart

There are a large number of diseases and pathologies that are diagnosed by echocardiography:

ischemic disease;
myocardial infarction or pre-infarction condition;
arterial hypertension and hypotension;
congenital and acquired heart defects;
heart failure;
rhythm disturbances;
rheumatism;
myocarditis, pericarditis, cardiomyopathy;
vegeto - vascular dystonia.

Ultrasound examination can also detect other disorders or diseases of the heart muscle. In the protocol of diagnostic results, the doctor makes a conclusion, which displays the information obtained from the ultrasound machine.

These results of the examination are considered by the attending cardiologist and, in the presence of deviations, prescribe therapeutic measures.

The decoding of an ultrasound of the heart consists of multiple points and abbreviations that are difficult to make out for a person who does not have a special medical education, so we will try to briefly describe the normal indicators obtained by a person who does not have abnormalities or diseases of the cardiovascular system.

Deciphering echocardiography

Below is a list of abbreviations that are recorded in the protocol after the examination. These figures are considered normal.

Mass of the myocardium of the left ventricle (MMLV):
Left ventricular myocardial mass index (LVMI): 71-94 g/m2;
End-diastolic volume of the left ventricle (EDV): 112±27 (65-193) ml;
End-diastolic size (KDR): 4.6 - 5.7 cm;
Final systolic size (CSR): 3.1 - 4.3 cm;
Wall thickness in diastole: 1.1 cm
Long axis (DO);
Short axis (KO);
Aorta (AO): 2.1 - 4.1;
Aortic valve (AK): 1.5 - 2.6;
Left atrium (LP): 1.9 - 4.0;
Right atrium (PR); 2.7 - 4.5;
The thickness of the myocardium of the interventricular septum diastological (TMIMZhPd): 0.4 - 0.7;
The thickness of the myocardium of the interventricular septum systological (TMIMZhPs): 0.3 - 0.6;
Ejection fraction (EF): 55-60%;
Mitral valve (MK);
Myocardial movement (DM);
Pulmonary artery (LA): 0.75;
Stroke volume (SV) - the amount of blood volume ejected by the left ventricle in one contraction: 60-100 ml.
Diastolic size (DR): 0.95-2.05 cm;
Wall thickness (diastolic): 0.75-1.1 cm;

After the results of the examination, at the end of the protocol, the doctor makes a conclusion in which he reports on the deviations or norms of the examination, also notes the alleged or exact diagnosis of the patient. Depending on the purpose of the examination, the state of health of the person, the age and gender of the patient, the examination may show slightly different results.

A complete transcript of echocardiography is evaluated by a cardiologist. An independent study of the parameters of cardiac parameters will not give a person complete information on assessing the health of the cardiovascular system if he does not have a special education. Only an experienced doctor in the field of cardiology will be able to decipher the echocardiography and answer the patient's questions.

Some indicators can slightly deviate from the norm or be recorded in the examination protocol under other items. It depends on the quality of the device. If the clinic uses modern equipment in 3D, 4D images, then more accurate results can be obtained, on which the patient will be diagnosed and treated.

Ultrasound of the heart is considered a necessary procedure, which should be carried out once or twice a year for prevention, or after the first ailments from the cardiovascular system. The results of this examination allow a specialist doctor to detect cardiac diseases, disorders and pathologies in the early stages, as well as to treat, give useful recommendations and return a person to a full life.

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When is it necessary to do an ultrasound of the heart?

The clinic of many diseases (gastrointestinal tract, nervous system, respiratory organs) is similar to that in cardiac pathologies. To correctly diagnose, it is necessary to do an ultrasound of the heart in the case when the following symptoms occur:

nausea, accompanied by jumps in blood pressure;
persistent headaches; dizziness up to loss of consciousness;
weakness;
persistent cough;
dyspnea;
swelling (legs, torso);
cardiac arrhythmias;
palpitations or a feeling of fading of the heart muscle;
pains of different localization: in the upper abdomen, in the right hypochondrium, in the chest, under the shoulder blade on the left, behind the sternum;
enlarged liver;
cold extremities;
pale, with a bluish tinge, skin;
hyperthermia on the background of shortness of breath, chest pain and cyanosis, as well as the appearance of these symptoms after taking alcohol;
murmurs are heard on auscultation.

It is this study that allows you to confirm or exclude heart damage.

Indications

There are a number of diseases in which the heart "suffers". These include:

scleroderma;
angina;
rheumatism;
myocardial dystrophy;
congenital anomalies and acquired defects;
systemic pathologies (lupus erythematosus, etc.);
a history of myocardial infarction;
arrhythmias;
vascular aneurysm;
tumor formations;
arterial hypertension (including hypertension);
heart murmurs of unknown etiology.

In the presence of these pathologies, ultrasound examination makes it possible to timely notice the appearance of any deviations (both anatomical and functional), and take adequate measures.

Ultrasound of the heart is performed in cases where it is necessary to establish the cause of changes in the ECG, the type of heart failure, as well as to assess the functional state of the organ in athletes and in people who have undergone heart surgery.

The procedure is safe and can be performed on patients of all ages. Directions are not required. If the doctor recommends it, where to do an ultrasound of the heart, the patient himself must decide, based on his financial capabilities. The cost of an ultrasound of the heart varies from 1200 to 4500 rubles (depending on the level of the medical institution, the qualifications of the specialist and the volume of the necessary examination).

When should an ultrasound be done on a child?

Ultrasound of the heart of the child must be done in the case when the following violations occur:

causeless loss of consciousness;
deviations in the cardiogram;
the presence of murmurs in the heart;
frequent colds;
hereditary burden (close relatives had cardiac pathologies);
the baby has difficulty sucking a bottle (or breast);
the child talks about unpleasant and painful sensations in the chest area;
in a baby (even at rest), the color of the skin around the mouth, as well as on the arms and legs, changes;
with little physical exertion, the child sweats a lot, gets tired quickly.

If parents want to know if their baby's heart is healthy, it is necessary to examine the organ. Where can I do an ultrasound of the heart, the doctor will tell. Information on how much an ultrasound of the heart costs is specified by phone at the medical registrar or on the website of the medical institution. Prices for this service range from 1200-2500 rubles.

ultrasound of the fetus

For early diagnosis of diseases of the cardiovascular system, ultrasound of the fetal heart is performed already at the early stages of embryonic development.

A woman comes to the first ultrasound examination at a period of 6-8 weeks. Fixing the indications of ultrasound of the fetal heart during pregnancy at this stage, the doctor pays attention to the heart rate. Normally, this indicator is in the range of 110-130 beats / min. If the heart rate is higher than the indicated figures, this indicates an insufficient supply of oxygen to the organs and tissues of the embryo. At low rates of heart rate, some pathologies from the heart muscle are possible.

In the early stages, by ultrasound of the fetal heart, you can find out how many babies a woman is carrying.

When the expectant mother comes for an ultrasound of the heart at a later stage of pregnancy, the doctor evaluates not only the number of heartbeats per minute, but also the correct development of the organ, the presence (or absence) of defects.

At week 20, the cardiac chambers and their structures are well visualized. And to see any deviations for an experienced specialist is not difficult. If a future baby has a heart pathology, treatment can be started immediately after his birth.

What information does ultrasound provide?

When resorting to this diagnostic method, the patient is interested in the question: what does an ultrasound of the heart show. The first thing the doctor pays attention to is morphological parameters. These include: the size of the organ and its parameters, the volume and thickness of the walls of its chambers, the condition of the valvular apparatus, blood vessels, the presence of cicatricial changes or blood clots (if any). The functional activity of the heart is also assessed: the frequency of contractions, the rhythm of work, etc. the state of the pericardium and myocardium is assessed.

Interpretation of the results of an ultrasound examination of the heart

At the end of the ultrasound, the doctor fills out the examination protocol with (decoding of the ultrasound of the heart and conclusion). In the protocol, opposite each parameter, the indicators of the norm of ultrasound of the heart are indicated, with which the data of the subject are compared.

Norm indicators for the left ventricle

Normal heart ultrasound readings may vary depending on the gender of the patient.

Myocardial mass - 95-141g (for women), 135-182g (for men).

Myocardial mass index (LVMI) - 71-89g/m2 (for women), 71-94g/m2 (for men).

The final diastolic size is from 4.6 to 5.7 cm.

The end-systolic size is from 3.1 to 4.3 cm.

The wall thickness outside the contraction of the heart (in the diastole phase) is about 1.1 cm. If this indicator is increased, this is indicated by the term "hypertrophy". This change is most often associated with increased stress on the heart muscle.

The ejection fraction is 55-60%. Shows how much blood (in volume) the heart ejects at the time of the next contraction (in relation to the total amount of blood in the organ). Low numbers of this indicator indicate heart failure. Stroke volume (60-100 ml) - this is how much blood is normally ejected by the left ventricle at the time of systole.

Indicators of the norm for the right ventricle

The pancreas size index is from 0.75 to 1.25 cm / m2.

The wall thickness of the pancreas is 4-5mm.

Size at rest (diastolic) - from 0.95 to 2.05 cm.

Norm indicators for the interventricular septum

The thickness in diastole is in the range of 0.75 - 1.1 cm.

The excursion indicator (or deviation in both directions during contraction) ranges from 0.5 to 0.95 cm. With heart defects, it increases significantly.

Indicators of the norm for the right atrium

The main parameter for this chamber is EDV (end diastolic volume). The limits of its norm are quite wide - from 20 to 100 ml.

Indicators of the norm for the left atrium

LP size index - from 1.45 to 2.90 cm / m2.

Size - from 1.85 to 3.30 cm.

Deviations in the operation of the valves (1-3 degrees)

Insufficiency is a pathological condition in which the valve leaflets are not able to fully close. This leads to a partial return of blood in the opposite direction, which reduces the efficiency of the functioning of the heart muscle.

Stenosis is the opposite of insufficiency. It is characterized by a narrowing of the opening of a certain valve of the heart, which creates an obstacle for the passage of blood from chamber to chamber or vascular bed. As a result, wall hypertrophy develops.

Relative insufficiency - the valve is normal, but there are pathological changes in the heart chambers into which blood passes through it.

The norm for ultrasound for the pericardium

The pericardial sac most often undergoes an inflammatory process (pericarditis). As a result, fluid accumulates in its cavity, adhesions form on the walls. Normally, the volume of exudate does not exceed 30 ml. With its increase, additional pressure is exerted on the organ, which greatly complicates its functioning.

Another indicator is the thickness of the aorta, which is normally 2.1-4.1 cm.

If during the examination small deviations from the normal parameters of the ultrasound of the heart are found, you should not make a self-diagnosis. It is necessary to consult a doctor. Gender, age, concomitant diseases - something that can affect the final result. Deciphering the norm of ultrasound of the heart, as well as existing inconsistencies, can only be dealt with by a qualified cardiologist.

How an ultrasound is performed

Special preparation for ultrasound of the heart is not required. All that is needed from the patient to obtain the most objective results: calm down and breathe evenly. Immediately before the examination, you should not physically overstrain, drink caffeinated drinks, take medications (sedatives, etc.).

You can find out in detail how an ultrasound of the heart is done on the Internet. On the websites of many medical centers, along with a description of the procedure itself, the price of an ultrasound of the heart, visual materials are presented in the form of photographs and videos of an ultrasound of the heart.

Before examining the heart, the patient undresses to the waist and lies down on the couch. All jewelry from the exposed area (chains, etc.) must be removed. The procedure is non-invasive. First, the subject lies on his back, then on his right side. The chest area is treated with gel. Then, by moving the sensor over the surface of the skin in the projection area of the organ, the heart is examined. The whole procedure takes no more than 20 minutes. The monitor displays the heart and surrounding structures, which is made possible by the property of ultrasound. It is reflected from the fabric, and, depending on their density, gives the corresponding picture.

Ultrasound of the heart allows you to diagnose pathologies that have not yet begun to manifest symptomatically.

The increase in myocardial mass is based on, that is, a thickening that characterizes a structural rearrangement in the heart muscle, which forces doctors not only to conduct dynamic monitoring, but also to switch to active treatment tactics.

Modern recommendations regarding the therapy and diagnosis of various pathologies of the heart indicate that the mass of the myocardium of the left ventricle (LV) is not only possible, but also necessary to control, and for this, periodic ultrasound examinations of the heart are included in the protocols for managing patients with a risk of cardiac hypertrophy.

The norm of myocardial mass for men, on average, is considered to be in the range of 135 - 182 g, for women - 95 - 141 g.

Reasons for the deviation of the mass and mass index of the heart from normal numbers

The mass of the myocardium is increased in pathological processes leading to its overload:

The increase in muscle tissue mass occurs and is normal- with enhanced physical training, when intense sports cause an increase not only in skeletal muscles, but also in the myocardium, which provides the organs and tissues of the trainee with oxygen-rich blood.

Athletes, however, run the risk of eventually moving into the category of people with myocardial hypertrophy, which under certain conditions can become pathological. When the thickness of the heart muscle becomes greater than the coronary arteries are able to provide blood, there is a risk of occurrence. It is with this phenomenon that is most often associated with well-trained and outwardly quite healthy people.

Thus, an increase in myocardial mass, as a rule, indicates a high load on the heart, whether during sports training or pathological conditions, but regardless of the cause, cardiac muscle hypertrophy deserves close attention.

Methods for calculating myocardial mass and mass index

Calculation of myocardial mass and its index is based on data in different modes, while the doctor must use all the possibilities of instrumental examination, correlating two- and three-dimensional images with Doppler data and using additional capabilities of ultrasound scanners.

Today, the situation has improved somewhat, largely due to more modern ultrasound diagnostic devices, which allow only minor errors, but there are still several calculation formulas for determining the mass of the myocardium of the left ventricle (LV). The most accurate of them are the two proposed by the American Society of Echocardiography (ASE) and the Penn Convention (PC), which take into account:

The thickness of the heart muscle in the septum between the ventricles;
The thickness of the posterior LV wall at the end of the period of filling with blood and before the next contraction;
End-diastolic size (EDD) of the left ventricle.

The formula for determining the mass of the myocardium looks like this:

0.8 x (1.04 x (MZHP + KDR + ZSLZH) x 3 - KDR x 3) + 0.6, where IVS is the width of the interventricular septum in centimeters, EDD is the end-diastolic size, ZSLZh is the thickness of the posterior wall of the left ventricle in centimeters.

The norm of this indicator differs depending on gender. Among men, the range of 135-182 g will be normal, for women - 95-141 g.

In addition to the objectivity of assessing the mass of the myocardium, there is another problem: the need to identify clear indexing criteria to determine the presence and degree of hypertrophy, because the mass has a direct relationship with the size of the body of the subject.

The mass index is calculated as follows:

IM=M/N2.7 or M/P, where M is the muscle mass in grams, P is the height of the subject, P is the body surface area, m2.

The form of an echocardiographic study usually indicates lower average standards for the mass index relative to the body surface: 71-94 g / m2 for men and 71-89 g / m2 for women (different formulas are used, therefore, the indicators may differ). These limits characterize the norm.

If the mass of the myocardium is correlated with the length and area of the body, then the range of variation in the norm of the indicator will be quite high: 116-150 for men and 96-120 for women when taking into account body area, 48-50 for men and 45-47 for women when indexed by height .

Thus, myocardial mass and mass index are parameters that make it possible to judge the risk or presence of cardiac muscle hypertrophy. Interpretation of the results of echocardiography is a difficult task, which is within the power of a specialist with sufficient knowledge in the field of functional diagnostics. In this regard, independent conclusions of patients are far from always correct, therefore, it is better to go to a doctor to decipher the result in order to exclude false conclusions.

The average value of the mass index of the left ventricular myocardium is 71 g/m2 in men and 62 g/m2 in women. The upper limit of this index is 94 and 89 g/m2, respectively.

The causes and mechanism of changes in the mass of the left ventricle in various diseases are still poorly understood.

The blood vessels that feed this organ do not keep up with its growth, so starvation of the heart tissues occurs and various diseases develop. With myocardial hypertrophy, problems also arise in the conduction system of the heart, as a result of which zones of abnormal activity appear in it and arrhythmias appear.

Formula

The mass of the myocardium of the left ventricle (calculation) is determined by the following formula:

MI - myocardial mass index is determined by the formula:

MI=M/H2.7 or MI=M/S where

M is the mass of the myocardium of the left ventricle (in g);
H - height (in m);
S is the surface area of the body (in m2).

Causes

Causes of left ventricular hypertrophy include:

arterial hypertension;
various heart defects;
cardiomyopathy and cardiomegaly.

The mass of the myocardium of the left ventricle in 90% of patients with arterial hypertension exceeds the norm. Often hypertrophy develops with mitral valve insufficiency or with aortic defects.

The reasons why myocardial mass may exceed the norm are divided into:

Stages and symptoms

In the process of increasing the mass of the myocardium, three stages are distinguished:

compensation period;
subcompensation period;
decompensation period.

Consequences of left ventricular myocardial hypertrophy

High blood pressure not only makes you feel worse, but also provokes the onset of pathological processes that affect target organs, including the heart: with arterial hypertension, left ventricular myocardial hypertrophy occurs. This is due to an increase in the content of collagen in the myocardium and its fibrosis. An increase in myocardial mass entails an increase in myocardial oxygen demand. Which, in turn, leads to ischemia, arrhythmia and dysfunction of the heart.

Cardiac hypertrophy (increased mass of the myocardium of the left ventricle) increases the risk of developing cardiovascular disease and can lead to premature death.

Treatment

The method of treating left ventricular myocardial hypertrophy depends on the cause that caused the development of this pathology. If necessary, surgery may be prescribed.

Heart surgery for myocardial hypertrophy can be aimed at eliminating ischemia - stenting of the coronary arteries and angioplasty. With myocardial hypertrophy due to heart disease, if necessary, prosthetic valves or dissection of adhesions are performed.

Medicines prescribed by doctors for left ventricular hypertrophy are aimed at improving myocardial nutrition and normalizing heart rhythm. When treating myocardial hypertrophy, you should stop smoking (nicotine reduces the supply of oxygen to the heart) and drinking alcohol (many drugs used in myocardial hypertrophy are not compatible with alcohol).

Myocardial mass index

<0,001) (ММЛЖ, гр = 1,04×[(КДР+МЖП+ЗСЛЖ) 3 -КДР 3 ]-13,6) .

<0,001), переоценивала наличие ГЛЖ лишь на 6%, а чувствительность у пациентов с ГЛЖ (масса миокарда при аутопсии ><0,001), но систематически переоценивала наличие ГЛЖ (в среднем на 25%), что было устранено введением скорректированного уравнения (формула ASE): ММЛЖ=0,8×(ММЛЖ-кубическая формула)+0,6 гр. Однако, при её использовании наблюдалась недооценка ММЛЖ при аутопсии в пределах 30% .

<150 гр,гр - умеренной, а >

<90 гр/м она составила 4,7% против 12,2% при ИММЛЖ ≥140 гр/м, у женщин - 4,1% и 16,1% соответственно . Наблюдался рост ССЗ при более высокой ММЛЖ у мужчин в 2,6, а у женщин - в 3,9 раза, что доказывает прогностическую значимость и важность правильной оценки массы миокарда, поиска более точных диагностических критериев ГМЛЖ для раннего её выявления.

J.K. Galy, 1992

I.W. Hammond, 1986

E.Aberget, 1995

De G. Simone, 1994

Not gender sensitive

M.J. Koren, 1981

De G. Simone, 1995

<0,001)

All methods except dependent

Bibliographic link

URL: http://science-education.ru/ru/article/view?id=23603 (date of access: 03/10/2018).

candidates and doctors of sciences

Modern problems of science and education

Myocardial mass: essence, norm, calculation and index, as it says

The norm of myocardial mass for men, on average, is considered to be in the range of r, for women - r.

How is the mass of the myocardium of the left ventricle calculated at home?

The principle of calculating the mass of the LV myocardium

Causes affecting the deviation of the LV mass index of the myocardium from the norm

In most cases, the left ventricle and the myocardium as a whole increase under the influence of certain pathologies that provoke their significant overload of the heart:

valve defects;
cardiomyopathy;
arterial hypertension;
myocardial dystrophy.

Methods for calculating the mass of the left ventricle of the myocardium

The very norm of the myocardial mass index is calculated in many ways, but today medicine uses only the two most effective formulas: ASE and PC, which include the following data:

the thickness of the heart muscle between the right and left ventricles;
the thickness of the posterior cavity of the left ventricle (this indicator is measured in two stages: when the organ is completely filled with blood and when it is emptied);
end-diastolic dimensions of the left ventricle.

The abbreviations in this formula have the following designations:

IVS - the width of the septum between the ventricles, expressed in cm;
EDD - LV end-diastolic size;
ZLVZh - an indicator of the thickness of the posterior cavity of the left ventricle, expressed in cm.

Depending on who the patient is (male or female), the norm of the myocardial mass index will be slightly different. This difference looks like this:

If the patient is a man, then the norm for him will be from 135 to 182 grams;
If the patient is a woman, then for her the norm ranges from 95 to 141 grams.

With an overestimated indicator, it can be assumed that hypertrophy is rapidly developing in the patient's body, requiring urgent medical intervention.

Calculation of myocardial mass depending on the weight and height of the patient

As for the calculation of the ratio of myocardial mass to height and body weight, it is performed strictly according to the following formula:

The abbreviation of this formula is deciphered as follows:

M is the weight of the muscle, expressed in grams;
P is the patient's height;
P - the area of the patient's body, expressed in square meters.

Calculation of the mass of the myocardium of the left ventricle

Calculation of the mass of the myocardium of the left ventricle is carried out in the diagnostic study of the heart. The resulting value characterizes the internal state of the heart chamber. These measurements are studied in order to identify pathological disorders in its structure, to assess the ability to perform the main function. The task of the myocardium of the left ventricle is to perform rhythmic contractions that push blood under high pressure into the aorta. It is vital for continuous blood supply to the whole organism.

Norm indicators

The weight of the heart muscle is measured in grams and calculated according to the formula, the terms of which are obtained from echocardiography. Particular attention is focused on the state of the left ventricle. This is due to its significant functional load and greater susceptibility to change than the right one.

There is an established norm for the mass of the myocardium of the left ventricle. Its boundaries change depending on the gender of the patient, which is displayed in the table:

The data obtained during the instrumental examination must be correlated with the weight, physique and physical activity of a particular person.

This is necessary to explain possible deviations from the norm. Patient parameters, occupation, age, previous surgery or heart disease play a role in determining the cause of myocardial changes.

The heart muscle mass of a fragile woman differs from the indicator of a man's athletic physique, and this makes up the range of normative parameters.

Taking into account the height and weight characteristics of the patient, the mass index of the myocardium of the left ventricle is calculated, its norm is given in the table:

Mass and myocardial index are two diagnostic parameters that reflect the internal state of the heart and indicate the risk of circulatory disorders.

Hypertrophy

The thickness of the myocardium of the left ventricle is normally measured when it is relaxed, and is 1.1 cm. This indicator is not always saved. If it is elevated, then myocardial hypertrophy on the left is ascertained. This indicates excessive work of the heart muscle and can be of two types:

Physiological (growth of muscle mass under the influence of intense training);
pathological (enlargement of the heart muscle as a result of the development of the disease).

If the wall thickness of the left ventricle is from 1.2 to 1.4 centimeters, slight hypertrophy is recorded. This condition does not yet indicate pathology and can be detected during a medical examination of athletes. With intensive training, there is an increase in skeletal muscles and at the same time myocardial muscles. In this case, you need to monitor changes in cardiac muscle tissue using regular echocardiography. The risk of transition of physiological hypertrophy into a pathological form is very high. Thus, sports can harm health.

When the heart muscle changes up to two centimeters, the states of medium and significant hypertrophy are considered. They are characterized by the appearance of shortness of breath, a feeling of lack of air, pain in the heart, a violation of its rhythm and increased fatigue. Timely detected this change in the myocardium is amenable to medical correction.

An increase over 2 centimeters is diagnosed as high degree hypertrophy.

This stage of myocardial pathology is life-threatening due to its complications. The treatment method is selected according to the individual situation.

The principle of determining the mass

The definition of myocardial mass is calculated using the numbers obtained in the process of echocardiography. For the accuracy and objectivity of the evaluation of measurements, they are carried out in a combination of modes, comparing two- and three-dimensional images. The data is supplemented by the results of Doppler studies and indicators of ultrasound scanners, which are able to display a projection of the heart in natural size on the monitor screen.

Calculation of myocardial mass can be done in several ways. Preference is given to the two formulas ASE and PC, in which the following indicators are used:

the thickness of the muscular septum separating the cardiac ventricles;
directly the thickness of the posterior wall of the left chamber in a calm state, until the moment of its contraction;
full size of the relaxed left ventricle.

Interpretations of values obtained from echocardiography should be considered by an experienced specialist in functional diagnostics. In evaluating the results, he will note that the ASE formula represents the left ventricle along with the endocardium (the membrane of the heart that lines the chambers). This may cause distortion of its thickness measurement.

Formula

All measurements are taken in centimeters. Each abbreviation means:

You can measure the myocardial index using one of the formulas:

The meanings of the accepted abbreviations mean:

In measurements, the indicator of the area of \u200b\u200bthe test is used, because it is a more accurate value than body weight. This is due to the limitation of dependence on excessive amounts of adipose tissue. The surface area is calculated according to a fixed formula, where the parameters change according to the age of the patient.

The myocardial index is most indicative in pediatrics. This is due to the fact that the height of an adult remains unchanged during calculations over several years of the survey. The growth of the child is constantly changing, thanks to which it is possible to accurately track pathologies in cardiac parameters.

Myocardial mass index

Sinus bradyarrhythmia
diastolic dysfunction
Atrial fibrillation
Hypertension syndrome
myocardial infarction

Reasons for the deviation of the mass and mass index of the heart from normal numbers

The mass of the myocardium is increased in pathological processes leading to its overload:

Arterial hypertension;
valve defects;
Cardiomyopathy and myocardial dystrophy.

Methods for calculating myocardial mass and mass index

The thickness of the heart muscle in the septum between the ventricles;
The thickness of the posterior LV wall at the end of the period of filling with blood and before the next contraction;
End-diastolic size (EDD) of the left ventricle.

The formula for determining the mass of the myocardium looks like this:

The norm of this indicator differs depending on gender. Among men, the range d will be normal, for women - r.

The mass index is calculated as follows:

IM=M/H2.7 or M/P, where M is the muscle mass in grams, P is the height of the subject, P is the body surface area, m2.

Left ventricular myocardial hypertrophy (LVH), as an element of its structural restructuring, is considered a sign of morphological deviation from the norm, a clear predictor of an unfavorable prognosis of the disease that caused it, as well as a criterion that determines the choice of active treatment tactics. Over the past twenty years, clinical studies have been conducted that have proven the independent contribution of drug-induced reduction in LV myocardial mass (LVML) in patients with arterial hypertension (AH), which makes it necessary to determine and control LVMM. Based on these ideas, recent recommendations on the diagnosis and treatment of hypertension include the measurement of LVML in the algorithm of antihypertensive management of patients in order to determine the presence of LVH.

When measuring LVML, researchers are faced with multifactorial factors that have an impact on it. This is both the dependence of LVML on body size, and the possibility of only an adaptive increase in LVML, for example, during physical activity. There are also different sensitivity of instrumental methods for determining LVMM: some authors tend to have a higher sensitivity of MRI measurement.

The correction of LVML to BSA, calculated according to the Du Bois formula, is more often used, but this standardization is imperfect, because it underestimates LVML in people with obesity.

The above ambiguous ideas about the normal values of LVMI, LVMI and LVH criteria are presented in Table 1.

LVMI as a criterion for LVLV with and without gender

D. Levy, Framingham Research, 1987

J.K. Galy, 1992

I.W. Hammond, 1986

E.Aberget, 1995

De G. Simone, 1994

J.J. Mahn, 2014

Recommendations for chamber quantification: Guidelines, 2005

Not gender sensitive

M.J. Koren, 1981

De G. Simone, 1995

Correspondence of the incidence of LVH according to different methods of its determination

(performance ratio (KFR) in %; p<0,001)

All methods except dependent

Onishchenko Alexander Leonidovich, Doctor of Medical Sciences, Professor, Vice-Rector for Research, SBEI DPO NGIUV MOH of Russia, Novokuznetsk;

Bibliographic link

URL: https://science-education.ru/ru/article/view?id=23603 (date of access: 09/02/2017).

The field of activity (technology) to which the described invention belongs

The know-how of the development, namely, this invention of the author belongs to the field of medicine and can be used to diagnose left ventricular myocardial hypertrophy.

DETAILED DESCRIPTION OF THE INVENTION

In cardiology practice, special attention should be paid to the diagnosis of left ventricular hypertrophy. This is due to the fact that, as shown by numerous studies, left ventricular myocardial hypertrophy is a more rigorous predictor of cardiovascular complications and mortality than blood pressure and other risk factors [Florya V.G. The role of left ventricular remodeling in the pathogenesis of chronic circulatory failure. // Cardiology, 1997, No. 5, p.63-69; Yurenev A.P., Gerashchenko Yu.S., Dubov P.B. On the prognosis of the course of the disease in hypertensive patients with coronary insufficiency. // Ter. arch. 1994; 66:4:9-11; Bikkina M., Levy D., Evans J.S et al. Left ventricular mass and risk of strok in an elderly cohort: the Framingham Heart Study. JAMA, 1994; 272; 33-36; Devereux R.B. Left ventricular geometry, pathophysiology and prognosis. J Am Coll Cardiol, 1995; 25:]. Even a small change in the mass of the left ventricle within normal values can serve as a prognostic sign of an increase in cardiovascular risk.

An increase in the mass of the left ventricle is a common final way of many adverse cardiovascular outcomes [Florya V.G. The role of left ventricular remodeling in the pathogenesis of chronic circulatory failure. // Cardiology, 1997, No. 5, p.63-69; Devereux R.B. Left ventricular geometry, pathophysiology and prognosis. J Am Coil Cardiol, 1995; 25:].

According to the Framingham Study, individuals 35 to 64 years of age with electrocardiographic evidence of LVH are 3 to 6 times more likely to develop cardiovascular disease than those without LVH. After the appearance of ECG signs of LVH, 35% of men and 20% of women die within 5 years; in older age groups, 5-year mortality among men and women reaches 50 and 35%, respectively.

Due to the important prognostic value, clear criteria are needed to diagnose LVH as early as possible and to dynamically monitor the process of cardiac remodeling. Currently, there are several ways to diagnose left ventricular myocardial hypertrophy.

The simplest and most accessible method is electrocardiography. There are the following ECG criteria for left ventricular hypertrophy:

Sokolov-Lyon index (SV1+RV5/RV6>35 mm) (sensitivity 22%, specificity 100%)

Cornell voltage index RaVL+SV3 >28 mm in men and >20 mm in women (sensitivity 42%, specificity 96%)

RaVL>11 mm (sensitivity 11%, specificity 96%). [Prevention, diagnosis and treatment of primary arterial hypertension in the Russian Federation. // Clinical pharmacology and therapy 2000, No. 9 (3), p.5-30].

Despite the high specificity of the electrocardiographic method (96-100%), it has a low sensitivity (22-42%), which does not allow it to be effectively used to solve the tasks.

From the patent literature, another method for diagnosing ventricular myocardial hypertrophy is known (ed. certificate No. class. A 61 B 5/02), including an electrocardiographic examination of the patient in conventional leads, characterized in that in order to increase the accuracy of determining the predominance of right or left ventricular myocardial hypertrophy hearts with their combined hypertrophy additionally determine the ratio of the amplitude of the R wave to the sum of the amplitudes of the Q, R, S waves in standard leads, the ratio of the amplitude of the R wave to the sum of the amplitudes of the R and S teeth in the chest leads V1 and V2, V4 and V5, summarize the obtained values in pairs taking into account their direction and value in leads III, V1, V2, V4 with the sign /+/, and in leads I, V5 - with the sign /-/ and the hypertrophy index (HI) is determined by the formula: IG=(R/(Q +R+S)III-R/(Q+R+S)I)+(R/(R+S)V1+R/(R+S)V2)+(R/(R+S)V4-R /(R+S)V5), where Q, R, S are the amplitudes of the ECG QRS complex teeth in leads I, III, V1, V2, V4, V5, mm left ventricular pertrophy with combined ventricular hypertrophy of the heart. This method allows only to determine the predominance of hypertrophy of one of the ventricles and cannot be used for its early diagnosis. The method is based on electrocardiographic criteria and, therefore, its sensitivity is insufficient.

The diagnosis of LVH can be established as a result of a pathoanatomical study (normally, the mass of the myocardium is 1/215 of the body weight in men and 1/250 of the body weight in women [Human Anatomy. Gain M.G., N.K. Lysenkov, V. I. Bushkovich, St. Petersburg, Hippocrates, 1997]), but it can only be performed posthumously, which significantly limits the possibilities of its application.

Currently, echocardiographic criteria are most often used to diagnose myocardial hypertrophy. The echocardiographic research method allows obtaining clear data, on the basis of which changes in the structure and function of the heart are assessed. In the diagnosis of LVH, this method is more sensitive than electrocardiography. Left ventricular myocardial mass, which can be calculated from echocardiographic data, is a more reliable predictor of morbidity and mortality.

Usually, echocardiography determines:

The thickness of the interventricular septum (IVS)

The thickness of the posterior wall of the left ventricle (ZSLZh),

Hypertrophy is spoken of in those cases when the IVS exceeds 10 mm, and the ZSLZh exceeds 11 mm [Strutynsky A.V. Echocardiogram: analysis and interpretation. // M., 2001], however, left ventricular hypertrophy can also be observed with normal values of the IVS and ZSLZH due to its dilation.

A more accurate echocardiographic sign of LVH is an increase in the mass of the left ventricular myocardium, which is calculated using the formula proposed by R.Devereux and N.Reichek:

where MMLZH - the mass of the myocardium of the left ventricle;

IVS - the thickness of the interventricular septum in diastole;

ZSLZh - the thickness of the posterior wall of the left ventricle in diastole;

The mass of the myocardium calculated in this way is not related to the constitutional features of the patient. That is why there is still no unity in understanding at what values of the mass of the myocardium of the left ventricle one can speak of LVH [Sidorenko B.A., Preobrazhensky D.V. Left ventricular hypertrophy: pathogenesis, diagnosis and possibility of regression under the influence of antihypertensive therapy. // Cardiology.; 5:80-85]. This disadvantage, on the one hand, significantly limits the use of the Devereux and Reichek formula in the diagnosis of myocardial hypertrophy in this patient, and on the other hand, does not allow the use of this indicator for epidemiological studies.

The mass of the myocardium largely depends on gender, anthropometric indicators of the human body [Human Anatomy. Weight gain M.G., N.K. Lysenkov, V.I. Bushkovich. SPb, Hippocrates, 1997], therefore, as a criterion for diagnosing LVH, the mass index of the left ventricular myocardium is used, calculated by the formula:

where IMM is the mass index of the myocardium of the left ventricle;

MMLV - mass of the myocardium of the left ventricle;

S is the surface area of the body.

The surface area of the body is calculated by the Dubois formula [Human Physiology in 2 volumes, ed. V.M. Pokrovsky and G.F. Korotko, M., Medicine, 2001 // V.2, p.119]:

S-m 0.425 h 0.725 71.84,

where m is the body weight;

The normal proportions of the human body, its organs and tissues, which are the basis for calculating the myocardial mass index, can change significantly under various pathological conditions. This is confirmed by the fact that different authors give different values of the mass index of the left ventricular myocardium as the lower limit for LVH in men and women [Sidorenko B.A., Preobrazhensky D.V. Left ventricular hypertrophy: pathogenesis, diagnosis and possibility of regression under the influence of antihypertensive therapy // Kardiologiya.; 5:80-85].

Myocardial mass index calculations are given in Tables 1-8.

When calculating the body surface area according to the Dubois formula, with an increase in body weight (with edema, obesity) by 25%, the body surface area will increase by about 10%, and with an increase in body weight by 50% - by about 19%. Accordingly, the decrease in the myocardial mass index (IMM) calculated using this formula will occur without changing the value of its real mass and morphological properties. Similarly, there is a formal increase in the myocardial mass index with a decrease in body weight (weight loss, dehydration of the body with vomiting, diarrhea, prescription of diuretics, etc.). In addition, it is impossible to focus on this indicator in people who have lost limbs, with developmental anomalies, due to the fact that the body surface area, body weight and height in such people are related by other ratios.

With age, a person's height decreases by 5-7 cm due to an increase in the curvature of the spine and a decrease in the thickness of the intervertebral discs [Textbook of anatomy for medical students, ed. prof. Sapina M.R. in 2 volumes, M., Medicine, 1987, T.1], which leads to the inadequacy of the use of this method for diagnosing myocardial hypertrophy in the elderly and senile. In addition, human height changes even during the day by 2-4 cm [Zhigulev N.M., Badzgaradze Yu.D., Zhigulev S.N. Osteochondrosis of the spine: a guide for physicians. - St. Petersburg .. - Publishing House "Lan", 592 p.].

In connection with the above, the myocardial mass index calculated on the basis of body surface area is a very unstable indicator, the use of which for the diagnosis of myocardial hypertrophy in a number of cases gives false positive and false negative results. This makes it impossible to use the myocardial mass index for dynamic monitoring of patients when it is necessary to evaluate, for example, the effectiveness of the therapy or the degree of prognostic risk in a given patient with myocardial hypertrophy.

The objective of the present invention is to achieve an objective criterion that allows diagnosing left ventricular myocardial hypertrophy, which could be used with equal success both for single use and for dynamic monitoring of a specific patient, as well as for epidemiological studies.

The solution of the problem is achieved by calculating the myocardial mass index based on the results of echocardiographic studies and anthropometric measurements. The method is carried out as follows.

The patient undergoes an echocardiographic study to determine the thickness of the interventricular septum, the thickness of the posterior wall of the left ventricle and the final diastolic size. After that, the mass of the myocardium of the left ventricle is calculated according to the formula:

where IVS is the thickness of the interventricular septum in diastole;

ZS - thickness of the posterior wall of the left ventricle in diastole;

KDR - end diastolic size of the left ventricle.

Then the patient is given anthropometric measurements (in cm):

a) the width of the forearm at the level of the styloid process of the ulna, d;

b) circumference of the forearm at the level of the styloid process of the ulna, p;

c) distance from the styloid process of the ulna to the apex of the olecranon of the ulna, L.

After that, the bone coefficient k is calculated by the formula:

It closely correlates (correlation coefficient r = 0.91) with body surface area in healthy people with normal body weight, does not change with a decrease or increase in unstable indicators that determine body surface area. Then calculate the mass index of the myocardium of the left ventricle (H i) according to the formula:

The criterion for the presence of hypertrophy of the myocardium of the left ventricle is the value of H i more than 0.6.

We propose an indicator that links the mass of the myocardium to the dimensions of the bones of the forearm, which are more stable than height and weight, which determine the surface area of the body.

The formation of the skeleton of the forearm ends by the age of 25, and the established proportions remain without significant changes until the end of a person's life [Textbook of anatomy for students of medical institutes, ed. prof. Sapina M.R. in 2 volumes, M., Medicine, 1987, T.1]. Pathological changes in soft tissues (edema, dehydration, excessive development of subcutaneous adipose tissue, weight loss) do not significantly affect the size of the bones.

The use of the ratio of myocardial mass to the indicator associated with the size of the bones of the skeleton makes it possible to exclude incorrect changes in the myocardial mass index that occur in the conditions described above. This makes it possible to monitor the dynamics of myocardial hypertrophy, for example, during therapeutic measures accompanied by a change in body weight. In addition, this makes it possible to adequately diagnose myocardial hypertrophy in patients without limbs (provided that at least one forearm is present), with developmental anomalies, etc.

The method can also be used to control myocardial hypertrophy in patients in cases where it is difficult to determine their height and weight (for example, in unconscious patients in skeletal traction, in a plaster cast, etc.).

Another advantage of our method is that the dynamics of myocardial mass can be assessed throughout the life of the patient and, therefore, be used in epidemiological studies. This is possible due to the fact that the value of the proposed bone coefficient k and the associated myocardial mass index will practically not change with age, while the body surface area may vary and lead to an incorrect change in the conventional mass index of the left ventricular myocardium.

Patient C, aged 55, diagnosis: Hypertension II st. ischemic heart disease. Angina pectoris II FC. CHF I st.

Upon admission to the hospital, the patient underwent electrocardiographic, echocardiographic and anthropometric studies.

The results of electrocardiography do not give grounds to diagnose myocardial hypertrophy in a patient. When using the proposed index H i, the diagnosis of hypertrophy is obvious.

Patient A, 78 years old, diagnosis: ischemic heart disease. Angina pectoris III FC. Hypertension II stage. CHF II B. Diabetes mellitus type II, moderate to severe course. Obesity III Art. Upon admission to the hospital, an echocardiographic study and anthropometric measurements were performed, the following results were obtained:

It can be seen from the tables that using the generally accepted IMM, we cannot diagnose myocardial hypertrophy, because this patient is overweight and we get a deliberately false result (BMI = 129.62) - the absence of hypertrophy. Using the new criterion H i (H i >0.6), we diagnose myocardial hypertrophy.

After the therapy, the patient's body weight changed (due to the disappearance of edema and a decrease in subcutaneous fat), after a second study, the following results were obtained:

Thus, based on the IMM, we can make a false conclusion that during the therapy the patient developed myocardial hypertrophy. (BMI increased from 129.62 to 140.59). If, however, the H i criterion is used as a criterion for left ventricular myocardial hypertrophy, it becomes obvious that the patient's real myocardial hypertrophy has not undergone any changes (H i remained equal to 0.62).

Patient B., aged 55, missing both lower limbs, diagnosis: Type II diabetes mellitus, severe course. Diabetic angiopathy of n / extremities. Stumps of both thighs. When carrying out the studies described above, it was obtained:

The use of IMM in this case is impossible, because. the calculated surface area does not reflect the normal proportions of the body and we get an incorrect result (BMI = 204.80), and therefore, we diagnose left ventricular myocardial hypertrophy even in its absence, using our method, we reject the diagnosis of hypertrophy.

Thus, the proposed method for diagnosing left ventricular myocardial hypertrophy using bone coefficient k and myocardial mass index H i allows you to adequately assess the presence or absence of left ventricular myocardial hypertrophy, conduct dynamic monitoring of a particular patient, and also makes it possible to use the data obtained in epidemiological studies .

Claim

A method for diagnosing left ventricular myocardial hypertrophy, which consists in the fact that the patient undergoes an echocardiographic study to determine the final diastolic size, the thickness of the myocardium of the posterior wall of the left ventricle in diastole, the thickness of the myocardium of the interventricular septum in diastole, the mass of the myocardium of the left ventricle according to the Devereux formula with the calculation of the myocardial mass index left ventricle, characterized in that the patient is additionally measured the width of the forearm between its lateral surfaces at the level of the styloid process of the ulna, the circumference of the forearm at the level of the styloid process of the ulna, the length of the ulna from the styloid process to the top of the olecranon process of the ulna, and based on the data obtained calculate the bone coefficient k:

where d is the width of the forearm at the level of the styloid process of the ulna;

p - circumference of the forearm at the level of the styloid process of the ulna;

L - the length of the ulna from the styloid process to the top of the olecranon of the ulna,

then the myocardial mass index is calculated taking into account the bone coefficient H i according to the formula:

with values greater than 0.6, left ventricular myocardial hypertrophy is diagnosed.

Inventor's name:

Name of the patentee: Kivva Vladimir Nikolaevich (RU); Maklyakov Yuri Stepanovich (RU); Pshenichkin Konstantin Ivanovich (RU); Slavskaya Natalya Alexandrovna (RU); Morozova Elena Aleksandrovna (RU); Ryabov Andrey Anatolievich (RU); Abramova Tatyana Nikolaevna (RU)

Postal address for correspondence:, Rostov-on-Don, st. Taganrog highway, 126/1, apt. 22, V.N. Kivve

Patent start date: 2004.12.23

There is an established norm for the mass of the myocardium of the left ventricle. Its boundaries change depending on the gender of the patient, which is displayed in the table:

The data obtained during the instrumental examination must be correlated with the weight, physique and physical activity of a particular person.

This is necessary to explain possible deviations from the norm. Patient parameters, occupation, age, previous surgery or heart disease play a role in determining the cause of myocardial changes.

The heart muscle mass of a fragile woman differs from the indicator of a man's athletic physique, and this makes up the range of normative parameters.

Taking into account the height and weight characteristics of the patient, the mass index of the myocardium of the left ventricle is calculated, its norm is given in the table:

Mass and myocardial index are two diagnostic parameters that reflect the internal state of the heart and indicate the risk of circulatory disorders.

Hypertrophy

Physiological (growth of muscle mass under the influence of intense training);
pathological (enlargement of the heart muscle as a result of the development of the disease).

An increase over 2 centimeters is diagnosed as high degree hypertrophy.

This stage of myocardial pathology is life-threatening due to its complications. The treatment method is selected according to the individual situation.

The principle of determining the mass

Calculation of myocardial mass can be done in several ways. Preference is given to the two formulas ASE and PC, in which the following indicators are used:

the thickness of the muscular septum separating the cardiac ventricles;
directly the thickness of the posterior wall of the left chamber in a calm state, until the moment of its contraction;
full size of the relaxed left ventricle.

What allows you to examine (EchoCG)

Treatment

The method of treating left ventricular myocardial hypertrophy depends on the cause that caused the development of this pathology. If necessary, surgery may be prescribed.

Consequences of left ventricular myocardial hypertrophy

Cardiac hypertrophy (increased mass of the myocardium of the left ventricle) increases the risk of developing cardiovascular disease and can lead to premature death.

When to perform (Echo CG)

The sooner there are diagnosed pathologies or diseases of the heart muscle, the greater the chance of a positive prognosis after treatment. Ultrasound should be performed with such symptoms:

recurrent or frequent pain in the heart;
rhythm disturbances: arrhythmia, tachycardia;
dyspnea;
increased blood pressure;
signs of heart failure;
transferred myocardial infarction;
if there is a history of heart disease;

You can undergo this examination not only in the direction of a cardiologist, but also other doctors: endocrinologist, gynecologist, neurologist, pulmonologist.

What diseases are diagnosed by ultrasound of the heart

There are a large number of diseases and pathologies that are diagnosed by echocardiography:

ischemic disease;
myocardial infarction or pre-infarction condition;
arterial hypertension and hypotension;
congenital and acquired heart defects;
heart failure;
rhythm disturbances;
rheumatism;
myocarditis, pericarditis, cardiomyopathy;
vegeto - vascular dystonia.

These results of the examination are considered by the attending cardiologist and, in the presence of deviations, prescribe therapeutic measures.

Stages and symptoms

In the process of increasing the mass of the myocardium, three stages are distinguished:

compensation period;
subcompensation period;
decompensation period.

Causes

Causes of left ventricular hypertrophy include:

arterial hypertension;
various heart defects;
cardiomyopathy and cardiomegaly.

The mass of the myocardium of the left ventricle in 90% of patients with arterial hypertension exceeds the norm. Often hypertrophy develops with mitral valve insufficiency or with aortic defects.

The reasons why myocardial mass may exceed the norm are divided into:

genetic;
biochemical;
demographic.

Normal values in adults and newborns

Formula

The mass of the myocardium of the left ventricle (calculation) is determined by the following formula:

0.8*(1.04*(MZHP+KDR+ZSLZH)*3-KDR*3)+0.6, where

IVS - value (in cm) equal to the thickness of the interventricular septum in diastole;
KDR - a value equal to the end-diastolic size of the left ventricle;
ZLVZH - a value (in cm) equal to the thickness of the posterior wall of the left ventricle in diastole.

MI - myocardial mass index is determined by the formula:

MI=M/H2.7 or MI=M/S where

M is the mass of the myocardium of the left ventricle (in g);
H - height (in m);
S is the surface area of the body (in m2).

Deviations from the norm and principles for decoding the results

As a result of echocardiography, it is possible to detect such pathologies of the development and functioning of the heart muscle and related diseases:

heart failure;
slowing, acceleration or interruptions in the heart rate (tachycardia, bradycardia);
pre-infarction state, myocardial infarction;
arterial hypertension;
vegetative-vascular dystonia;
inflammatory diseases: cardiac myocarditis, endocarditis, exudative or constrictive pericarditis;
cardiomyopathy;
signs of angina;
heart defects.

Left ventricular myocardial mass index: normal, increase. Myocardial mass: essence, norm, calculation and index, as indicated by Deciphering the results of an ultrasound examination of the heart

Formula

Causes

Stages and symptoms

Consequences of left ventricular myocardial hypertrophy

Treatment

Calculation of myocardial mass

Bibliographic link

Modern problems of science and education

Myocardial mass: essence, norm, calculation and index, as it says

Reasons for the deviation of the mass and mass index of the heart from normal numbers

Methods for calculating myocardial mass and mass index

Calculation of myocardial mass

Reasons for deviations

Research methods

Payment

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How is the mass of the myocardium of the left ventricle calculated at home?

The principle of calculating the mass of the LV myocardium

Causes affecting the deviation of the LV mass index of the myocardium from the norm

Methods for calculating the mass of the left ventricle of the myocardium

Calculation of myocardial mass depending on the weight and height of the patient

Why is an echocardiogram performed?

Normal values ​​in adults and newborns

Deviations from the norm and principles for decoding the results

Bibliographic link

What allows you to examine (EchoCG)

When to perform (Echo CG)

What diseases are diagnosed by ultrasound of the heart

Deciphering echocardiography

When is it necessary to do an ultrasound of the heart?

Indications

When should an ultrasound be done on a child?

ultrasound of the fetus

What information does ultrasound provide?

Interpretation of the results of an ultrasound examination of the heart

Norm indicators for the left ventricle

Indicators of the norm for the right ventricle

Norm indicators for the interventricular septum

Indicators of the norm for the right atrium

Indicators of the norm for the left atrium

Deviations in the operation of the valves (1-3 degrees)

The norm for ultrasound for the pericardium

How an ultrasound is performed

Reasons for the deviation of the mass and mass index of the heart from normal numbers

Methods for calculating myocardial mass and mass index

Formula

Causes

Stages and symptoms

Consequences of left ventricular myocardial hypertrophy

Treatment

Myocardial mass index

Bibliographic link

Modern problems of science and education

Myocardial mass: essence, norm, calculation and index, as it says

How is the mass of the myocardium of the left ventricle calculated at home?

The principle of calculating the mass of the LV myocardium

Causes affecting the deviation of the LV mass index of the myocardium from the norm

Methods for calculating the mass of the left ventricle of the myocardium

Calculation of myocardial mass depending on the weight and height of the patient

Calculation of the mass of the myocardium of the left ventricle

Norm indicators

Hypertrophy

The principle of determining the mass

Formula

Myocardial mass index

Reasons for the deviation of the mass and mass index of the heart from normal numbers

Methods for calculating myocardial mass and mass index

Bibliographic link

The field of activity (technology) to which the described invention belongs

DETAILED DESCRIPTION OF THE INVENTION

Claim

Hypertrophy

The principle of determining the mass

What allows you to examine (EchoCG)

Treatment

Consequences of left ventricular myocardial hypertrophy

When to perform (Echo CG)

What diseases are diagnosed by ultrasound of the heart

Normal values in adults and newborns

Normal values in adults and newborns