Hypertrophic cardiomyopathy is a disease of the muscular layer of the heart (myocardium) in which it is hypertrophy (increase in size). Most often affects the left ventricle. In this disease all the cavities of the heart, in contrast to dilated cardiomyopathy, or reduced in volume, or not change at all.
In other words, the growth (thickening) of the myocardium, which eventually may lead to serious violations of working not only the cardiovascular system but also the entire body.
The content of the article
Hypertrophy occurs in approximately 1% of the population. It is mainly observed in males. The average age at which detected this pathology ranges from 30 to 50 years. 15 – 25 % of patients suffering from hypertrophic cardiomyopathy, there is atherosclerosis of the coronary arteries (private vessels of the heart). The danger of the disease is the development of complications. Thus, about 10 % of patients are lesions of heart valves or infectious inflammation of the endocardium (inner layer of the heart). About half of the patients with hypertrophied heart die from severe ventricular arrhythmias, accompanied by circulatory failure.
Causes hypertrophic cardiomyopathy is a Proven hereditary theory of the origin of hypertrophic cardiomyopathy, but we cannot exclude the existence of other causes. The genetic component of this disease is transmission through the generations of defective genes that are responsible for the production of some proteins of the myocardium. Here we are talking about the different forms of myosin, troponin and tropomyosin. Under the influence of adverse factors, these genes may undergo mutations and cause other forms of hypertrophic cardiopathology.
In contrast to the hypertrophy of the myocardium at some cardiovascular diseases, the increase of the muscle layer in hypertrophic cardiomyopathy has no Association with heart defects, coronary artery disease or hypertension.
The mechanisms of the disease
The main mechanism by which this develops cardiomyopathy, is considered to be activation of compensatory mechanisms of the myocardium. This occurs in two cases:
- If disturbed diastolic function (incomplete relaxation of the walls of the heart during diastole).
- Violated if the output path of blood from heart chamber.
In the first case, the relaxation of the heart into the cavity of the left ventricle receives insufficient amount of blood. The result increases pressure. It is associated with reduced distensibility of the muscle layer.
When thickening of the interventricular septum occurs a malfunction of the mitral valve. This leads to a pressure difference between the initial aorta and colaclean space left ventricle. As a result, as in the first case, increases diastolic pressure in the cavity of the left ventricle.
In the end, these changes are accompanied by hypertrophy of not only the ventricles but also of the overlying left atrium. Then develops pulmonary hypertension (high blood pressure in the pulmonary vessels). This is due to subsequent dilatation of the left atrium.
Signs of hypertrophic cardiomyopathy consider thickening of the interventricular septum and the muscular layer of the left ventricle in the absence of dilatation of the cavities. Microscopic examination can detect the replacement of muscle tissue on the fibrous with chaotic arrangement of cardiomyocytes (muscle cells of the heart).
The main feature of cardiomyoplasty hypertrophic hypertrophic cardiomyopathy
Depending on the localization of the hypertrophied tissue, cardiomyopathy is divided into right and left ventricle. Left ventricular can be concentric (symmetric) and asymmetric. Mainly found asymmetric hypertrophy with predominant lesion of the interventricular septum. In addition, there are lesions posterior, posterolateral wall or apex of the heart. The latter form is called apical hypertrophy. Symmetric thickening of the heart walls is not more than 30 % of all cases.
Depending on the extent of myocardial damage distinguish obstructive and non-obstructive forms. The first option involves changing the gradient of the systolic pressure by reducing the cavity of the ventricle. Symmetrical hypertrophy usually does not cause obstruction of heart cavities.
Asymmetric thickening of the myocardium can be as obstructive and non-obstructive. Hypertrophy of the apex of the left ventricle is typically a non-obstructive variant unlike the others. We are talking about idiopathic hypertrophic subaortic stenosis (hypertrophy of the interventricular septum) and mesoventrite obstruction (thickening of the middle part of the interventricular septum).
Depending on the thickness of hypertrophied myocardium there are several degrees of the disease:
- from 1.5 to 2.0 cm and moderate;
- from 2.0 to 2.5 cm – medium;
- more than 2.5 cm – severe hypertrophy.
In addition, there are clinical and physiological classification depending on the magnitude of the pressure at the exit from the cavity of the left ventricle and symptoms, disturbing the patient.
Stage I: symptoms are not present, pressure does not exceed 25 mm Hg. article
Stage II: the complaint in the form of shortness of breath may occur during exercise, the pressure increased to 36 mm Hg. article
Stage III: shortness of breath and pain bothering at low loads, the pressure is increased to 44 mm Hg. article
Stage IV: there are circulatory disorders throughout the body, dramatically increases the risk of sudden cardiac death, the pressure can reach 80 mm Hg. article
The symptoms of hypertrophic cardiomyopathy
For a long time cardiomyopathy in the hypertrophic type has no symptoms. Clinical manifestations occur for 30 to 40 years. Despite the fact that most patients are looking for the same complaint, there are several clinical forms of the disease:
Nonobstructive form typically does not occur violations of the outflow of blood from the ventricle, so the symptoms of shortness of breath or arrhythmia can occur only during heavy physical activity.
Common symptoms cardiomyopathy obstruction are:
- shortness of breath;
- paroxysmal pain behind the sternum;
- dizziness and fainting;
- lowering blood pressure;
- various heart rhythm abnormalities.
Quite often the main and only symptom of cardiomyopathy in the hypertrophic type is sudden cardiac death.
Diagnosis of hypertrophic cardiomyopathy
In the diagnosis of this disease is often determined by a heart murmurs during the ejection of the blood and heart palpitations. Among the instrumental methods of research used:
- x-ray examination of the chest;
- monitoring Holter;
- the phonocardiography;
- rhythm – and polycardiography;
- sensing the left heart;
- coronary angiography;
- scan with the isotope of Thallium;
- MRI (magnetic resonance imaging) of the heart.
ECG changes little specific. However, you can detect the signs of hypertrophy of the heart and the change of repolarization. In this cardiomyopathy, it is advisable to perform differential diagnosis with other cardiac diseases.
Electrocardiogram results of the study of a patient suffering from hypertrophic cardiomyopathy
When echocardiography revealed a hypertrophied interventricular septum or other enlarged parts of the heart, impaired systolic function of the left ventricle.
The results of Echocardiography with the presence of hypertrophic cardiomyopathy in a patient
On x-ray often visible enlarged left ventricle and the same left atrium. In the later stages detected by expansion of the ascending part of the aorta and of the pulmonary artery branches.
At Holter monitoring there are bouts of atrial fibrillation, tachycardia and arrythmia.
Treatment of hypertrophic cardiomyopathy
Patients suffering from hypertrophic cardiomyopathy, shown moderate exercise. This is necessary in order to prevent the excessive pressure gradient in the left ventricle and the aorta.
Group of drugs used to treat:
- beta-blockers (Atenolol, Metoprolol…);
- calcium channel blockers (Nifedipine, Diltiazem…);
- antiplatelet agents (Aspirin, Acekard…).
With the development of heart failure in the regimen added to other group of drugs to compensate for the deficiency of blood circulation.
In the case of obstructive hypertrophic cardiomyopathy expedient for the prevention of endocarditis caused by various infections. Surgical treatment is indicated in severe cases. It involves removal of part of the myocardium or the mitral valve replacement. Sometimes you have to resort to implanting a permanent pacemaker.
Prognosis of hypertrophic cardiomyopathy
Variants of the disease are different. Non-obstructive hypertrophic cardiomyopathy with prolonged duration goes into heart failure. Perhaps the reverse development of the disease or transition in the dilatation cardiopathology. Sometimes the disease is complicated by infective endocarditis.
Without adequate treatment in 5 – 8 % of cases of hypertrophic cardiomyopathy complicated by ventricular fibrillation, myocardial infarction, or complete atrioventricular block (blocking of nervous impulse from the Atria to the ventricles). Very often the above complications lead to sudden death.
On this basis a fair conclusion that in the long course of the disease and the absence of adequate treatment of hypertrophic cardiomyopathy leads to life-threatening complications, which in most cases are fatal.