Diagnosis of hypertrophic cardiomyopathy

Diagnosis of hypertrophic cardiomyopathy is established on the basis of family history (cases of sudden death of relatives at a young age), complaints, results of physical examination. The information obtained through the instrumental survey is very important for establishing the diagnosis. The most valuable diagnostic methods are the ECG, which has not lost its importance at this time, and the two-dimensional Doppler echocardiography. In complex cases, differential diagnosis and clarification of the diagnosis are assisted by MRI and positron emission tomography. It is advisable to examine the relatives of the patient in order to identify family cases of the disease.

Clinical examination

With non-obstructive form of hypertrophic cardiomyopathy, there may be no abnormalities in examination, but sometimes an increase in the duration of the apical impulse and IV heart tone is determined.

In obstructive form of hypertrophic cardiomyopathy, signs of cardiac pathology are revealed. Among the most important include an enhanced long apical push that occupies the entire systole up to the 2nd tone (sign of myocardial hypertrophy of the left ventricle), systolic jitter along the left edge of the sternum, pulsation of the carotid arteries, rapid "jerky" pulse during palpation of the carotid arteries due to rapid expulsion of blood in the first half of the systole, systolic noise with localization at the apex of the heart and in the third to fourth intercostal space to the left near the edge of the sternum. Noise at the apex of the heart is attributed to mitral regurgitation, in the third to fourth intercostal space, infundibular left ventricular stenosis. The intensity of noise increases in the sitting position, standing, on exhalation, with a Valsalva test, i.e. With the aggravation of the obstacle to the expulsion of blood as a result of a decrease in pre- and post-loading or an increase in contractility. I tone on the apex of the heart in most cases of normal sonority, and the second tone on the ground in a number of patients is weakened, reveal the IV tone. Often determine the violation of the heart rate.

However, in some patients, systolic murmur is localized on the basis of the heart, unintentional and not accompanied by a decrease in the sonority of the second tone. In this case, the recognition of the disease is possible using additional research methods, in particular EchoCG.

Instrumental methods

Electrocardiography and 24-hour cardiogram monitoring

Interpretation of ECG data in patients with hypertrophic cardiomyopathy often presents great difficulties, which is connected with polymorphism of changes. Most often, such changes are revealed:

• voltaic signs of myocardial hypertrophy of the left ventricle and left atrium;
• disturbances in the process of repolarization of the ventricles - the most characteristic signs found in both non-obstructive and obstructive form of HCM are manifested by changes in the ST-T interval; changes in the amplitude of the T wave occur in different degrees of severity (from a moderate decrease in amplitude, especially in the left thoracic leads, before recording a deep negative G wave); conduction disturbance on the left leg of the bundle of the Hisnia, in particular, the blockade of its anterior branch is most often met from all heart blockages;
• the ventricular overexcitation syndrome in the form of shortening of the P-Q interval or the Wolff-Parkinson-White phenomenon is often recorded;
• registration of pathological Q waves in left pectoral and (rarely) standard leads is one of the typical electrocardiographic signs;
• heart rhythm disorders, which can cause syncopal conditions and sudden death, attract special attention of clinicians.

Daily monitoring of ECG data allows to identify the majority of patients with ectopic ventricular extrasystoles, attacks of ventricular tachycardia or supraventricular arrhythmia. In children, arrhythmias, especially ventricular arrhythmias, are much less common, although the frequency of sudden death is higher in them than in adults.

Radiography of chest organs

X-ray findings of the heart with hypertrophic cardiomyopathy are of little informative. In some patients, a slight increase in the left ventricular and left atrial arches and the rounding of the apex of the heart are noted, possibly an increase in the vascular pattern associated with overflow of the venous bed. In young children with hypertrophic cardiomyopathy, the cardiothoracic index ranges from 0.50 to 0.76.

Echocardiography

From non-invasive methods of research, echocardiography is the most informative method of diagnosis.

The main echocardiographic signs of hypertrophic cardiomyopathy are as follows.

• Hypertrophy of the myocardium of the left ventricle, the prevalence, localization and severity of which are very diverse. However, the most common form of hypertrophic cardiomyopathy is asymmetric hypertrophy of the interventricular septum, occupying either the entire interventricular septum (50% of cases), or localized in its basal third (25%) or two-thirds (25%). Less common are symmetrical hypertrophy, as well as other variants of hypertrophic cardiomyopathy - apical, mesoventricular and hypertrophy of the posterior-septal and / or lateral wall of the left ventricle.
• Reduction of the cavity of the left ventricle, associated with hypertrophy of the myocardium, both during diastole and in systole. This is an important morphological sign of the disease and one of the factors contributing to the violation of hemodynamics due to insufficient filling of the left ventricle during diastole.
• Dilation of the left atrial cavity.

In the obstructive form of HCMC, Doppler EchoCG reveals signs of obstruction of the left ventricular tract:

• the gradient of the systolic pressure between the left ventricle and the aorta can be of different degrees, sometimes reaching 100 mm Hg. And more;
• anteroposterior movement of the anterior valve of the mitral valve in the middle of the systole and the contact of the valves with the interventricular septum;
• middle-systolic aortic valve cover;
• mitral regurgitation.

In assessing the functions of the left ventricle according to EchoCG in most patients with hypertrophic cardiomyopathy, an increase in the ejection fraction is revealed, but an imbalance in the diastolic function of the myocardium, characterized by a decrease in the speed and completeness of active diastolic relaxation, is considered important.

Magnetic resonance imaging

This method makes it possible to most accurately assess morphological changes, assess the prevalence and severity of myocardial hypertrophy. Especially valuable method for diagnosis of the apical form of the disease and hypertrophy of the lower part of the interventricular septum and right ventricle.

Positron Emission Tomography

It allows to reveal and estimate the degree of violation of regional perfusion and myocardial metabolism.

Cardiac catheterization

Catheterization and angiocardiography were widely used in the early stages of the study of hypertrophic cardiomyopathy. Currently, they are performed much less often: in cases of concomitant heart pathology, in particular congenital heart disease, and when deciding on the surgical treatment of the disease.

The results of invasive research methods have shown that in young children, unlike schoolchildren and adults, obstruction of the output tract of both the left and the right ventricle is often determined. This, on the one hand, is associated with the fact that children die in the first months and years of life as a result of refractory heart failure, on the other hand, with the disappearance of obstruction of the outflow pathways of the left ventricle as the child grows due to changes in the relationship of the cardiac structures.

Differential diagnostics

When diagnosing, it is necessary to exclude diseases that have similar clinical manifestations, first of all, acquired and congenital heart defects (aortic aortic stenosis), essential hypertension. In addition, it is necessary to differentiate other possible causes of hypertrophy of the left ventricle, in particular, the "heart of the athlete".

[1], [2], [3], [4], [5], [6]