Hypertrophic cardiomyopathy (HCM) is a genetically determined cardiac disease in which the walls of the left ventricle (LV) are significantly thickened, which leads to a narrowing of the lumen of its outlet section and, consequently, to a decrease in the release of blood into the aorta. Malignant arrhythmias are common in people with HCM due to the disordered arrangement of muscle fibers.
Population prevalence
HCM occurs with a frequency of about 10 in 10,000 people. A little more often it is observed in the countries of South America, Western Europe, China and Japan. Mostly young people (25 - 35 years old) suffer. Men get sick much more often than women. Despite its low prevalence, HCM remains one of the most common causes of sudden cardiac death in young people.
The disease should not be confused with left ventricular hypertrophy with elevated blood pressure or heart disease. The second is also called "hypertensive heart" or "working myocardial hypertrophy", it develops as a compensatory muscle response in response to increased stress. With LV hypertension, it is necessary to overcome high vascular resistance, so it has to work with greater force. In some heart defects, due to malfunctioning of the valves, an increased volume of blood enters the LV, which must be "pushed" into the aorta and great arteries.
Myocardial hypertrophy differs from HCM in that the thickening of the LV walls occurs gradually and evenly. In HCM, in the overwhelming majority of cases, such changes are very pronounced and disproportionate, only separate parts of the LV are exposed to them - the upper or lower third of the interventricular septum, apex, etc.
The reasons for the appearance and the mechanism of development of violations
The main cause of hypertrophic cardiomyopathy is a genetic mutation. To date, about 11 genes are known, a change in which leads to the development of the described disease. They are responsible for the production of various proteins that make up the muscle fibers of the myocardium - troponins, light and heavy chains of myosin, actin, etc. Violation of the synthesis of one of them leads to thickening of the myocardium.
Most often, hypertrophy does not develop evenly, but only in one area of the LV. Particularly unfavorable is the thickening of the upper part of the interventricular septum, which narrows the lumen of the LV outlet. Due to pathological proliferation, muscle fibers begin to be arranged randomly. This creates conditions for the circulation of a nerve impulse, which contributes to the development of rhythm disturbances. In addition, the myocardium is replaced by connective tissue.
Another big problem of HCM is the occurrence of myocardial ischemia, i.e., a deterioration in the blood supply to the heart muscle.... There are two reasons for this: vascular compression by the hypertrophied myocardium and impaired relaxation of the organ (diastolic dysfunction). And, as you know, the heart itself is filled with blood precisely in the diastole phase.
Also, hypertrophic cardiomyopathy has more rare causes:
- hereditary diseases - Fabry disease, neurofibromatosis;
- neuromuscular diseases - Friedreich's ataxia;
- endocrine pathologies - acromegaly, pheochromocytoma;
- metabolic disorders - amyloidosis;
- the use of drugs - anabolic steroids, tacrolimus, hydroxychloroquine.
Symptoms
In the clinical picture of HCM, a typical triad of symptoms is distinguished:
- chest pain;
- rhythm disturbances;
- syncope - fainting.
Pain in the region of the heart is very similar to that of angina pectoris (pulling / squeezing pain behind the sternum, aggravated by physical exertion), because it is caused by myocardial ischemia. Its characteristic difference is that it not only does not relieve itself after taking Nitroglycerin, but can become even stronger. This is because the drug dilates blood vessels, which lowers blood pressure. This makes the heart beat faster. A high heart rate decreases the diastole phase, in which the blood supply to the myocardium occurs.
Fainting or light-headedness (dizziness, darkening in the eyes, feeling of "lightheadedness") occurs due to obstruction of the left ventricular outlet by a thickened myocardium, as a result of which the blood supply to the brain deteriorates. Various arrhythmias are also the cause of fainting.
The patient feels cardiac arrhythmias as heart palpitations and "interruptions". With HCM, dangerous arrhythmias often develop: paroxysmal ventricular tachycardia, ventricular fibrillation, atrioventricular blockade.
Due to the frequent occurrence of malignant rhythm disturbances, the risk of sudden cardiac death in patients with HCM is very high.
In the later stages of the disease, signs of chronic heart failure appear:
- general weakness, quickly approaching fatigue;
- shortness of breath, which increases when performing physical work or in a lying position;
- a feeling of heaviness or aching pain in the right side under the ribs due to an enlarged liver;
- swelling of the legs, especially noticeable in the evening.
I want to note that the presence of symptoms and its severity depend on the degree of thickening of the walls of the heart and the rapidity of the development of this process, which proceeds differently for everyone. Sometimes HCM quickly leads to disability, and someone may have an absolutely asymptomatic course, which accompanies a good prognosis.
Are there any early signs
A person with HCM can feel completely healthy for a long time and not experience any unpleasant sensations. The first symptoms are usually the sudden onset of chest pain or loss of consciousness while playing sports. If any of your family members have been diagnosed with HCM and you experience severe heart pain with dizziness, see your doctor as soon as possible.
Types of hypertrophic cardiomyopathy
There are several classifications of hypertrophic cardiomyopathy, dividing it according to different characteristics. In the first of them, family, hereditary and sporadic forms are distinguished. The latter develops against the background of other cardiac or systemic diseases.
By localization, there are:
- asymmetric HCM with and without obstruction - the upper and lower parts of the interventricular septum thicken;
- apical HCMP - the myocardium of the apex of the heart is hypertrophied;
- symmetric HCMP - a very rare form in which several muscle walls increase.
According to the level of pressure increase in the left ventricle, the following types are distinguished:
- I degree - pressure up to 25 mm Hg. Art .;
- II degree - pressure from 25 to 36 mm Hg. Art .;
- III degree - pressure from 36 to 44 mm Hg. Art .;
- IV degree - pressure above 45 mm Hg. Art.
Since the main danger to human life is hypertrophic cardiomyopathy with outflow tract obstruction, it is most often used hemodynamic classificationdescribed in the table below.
| A kind of HCMP | Left ventricular pressure readings | Clinical picture |
| Non-obstructive form | Pressure less than 30 mm Hg. Art. at rest and during stress test | No symptoms, or there is minor pain in the chest during physical work, attacks of rapid heartbeat |
| Latent form | Pressure less than 30 mm Hg. at rest, more than 30 mm Hg. with load test < | Frequent pain in the heart, discomfort of interruptions, dizziness, lightheadedness |
| Obstructive hypertrophic cardiomyopathy | The pressure exceeds 30 mm Hg. at rest | Severe chest pain, frequent loss of consciousness, signs of chronic heart failure (CHF). |
How to identify pathology and establish a diagnosis
Diagnosis of hypertrophic cardiomyopathy begins with questions about “familial” diseases, since HCM is a genetic disease. I clarify whether any of the patient's close relatives had a similar illness, whether any of the family members died at a young age from cardiac pathology - the diagnosis is most likely if the patient is between 20 and 40 years old.
During the examination, I try to pay great attention to auscultation of the heart. Quite often I manage to hear a systolic murmur in the III and IV intercostal space along the left edge of the sternum. Its severity indicates the degree of obstruction of the LV outlet.
Then I order additional research, which includes:
- electrocardiography (ECG);
- echocardiography (ultrasound of the heart, Echo-KG);
- coronary angiography.
On the electrocardiogram of patients with HCM, you can see:
- deep Q wave in leads II, III, aVF;
- signs of myocardial ischemia: decrease in the ST segment below the isoline, negative T wave;
- signs of left ventricular hypertrophy - high R waves in leads V4 - V6;
- various rhythm disturbances: fibrillation, atrial flutter, atrioventricular blockade, supraventricular and ventricular tachycardia.
Many arrhythmias can go unnoticed during normal ECG tape recording. Having seen a normal cardiogram in a person complaining of a rhythm failure, I assign him Holter (daily) ECG monitoring.
The main diagnostic method for HCM is echocardiography with Doppler mode. The following changes can be found on it:
- the thickness of the interventricular septum will be more than 15 mm, and the posterior wall of the LV - without pathology;
- high pressure in the LV outlet tract (more than 30 mm Hg);
- contact of the mitral valve leaflet with the IVS (phenomenon SAM);
- trembling of the aortic valve cusps at the time of systole.
Sometimes the patient is asked to do physical exercise (sit down 10 times). This allows to reveal the hidden obstruction of the LV outflow tract.
Coronary angiography is performed to assess the patency of the coronary arteries. I prescribe this procedure to those who have a high likelihood of atherosclerotic narrowing of the vessels supplying the heart (signs of coronary artery disease). At risk are people over 45 years of age, smokers, diabetes and hypertension.
Genetic testing to detect mutations is prescribed when routine tests do not provide an accurate diagnosis. I also recommend this method of examination to relatives of a HCM patient.
Treatment methods and life expectancy prognosis
Treatment for hypertrophic cardiomyopathy includes medication and surgery. Medicines are designed to maintain the condition and remove the symptoms of increasing complications. Only a heart transplant can completely save a person from the disease. But there are other surgical interventions that make the patient's life easier:
- ventricular septal myoectomy - An effective and frequently used method, which is the removal of a thickened area of the interventricular septum;
- septal alcohol ablation - chipping with ethyl alcohol of areas of hypertrophied myocardium, which leads to their death and a decrease in the thickness of the walls of the left ventricle;
- resynchronization - installation of special electrodes in the heart, which send appropriate signals. The peculiarity is that due to the procedure, the excitation wave goes with a slight delay and captures first the apex, then the septum of the organ, as a result of which the pressure in the left ventricle decreases, and the degree of obstruction of its outlet section decreases.
There are strict indications for surgical treatment of hypertrophic cardiomyopathy:
- high pressure in the LV outlet at rest (more than 50 mm Hg);
- pronounced thickening of the LV wall (more than 30 mm);
- bright clinical symptoms (pain, fainting).
With timely diagnosis, adequate treatment, the life expectancy of a patient with HCM may not differ from that of healthy people. The mortality rate in hypertrophic cardiomyopathy averages 1 to 6% per year.
Sudden death prevention and symptomatic relief
In order to facilitate symptoms of hypertrophic cardiomyopathyand, I prescribe the following drugs:
- beta-blockers (Bisoprolol, Metoprolol) - effective medicines that reduce the severity of clinical manifestations (shortness of breath, pain in the heart, heart attacks) and slow down the progress of the disease. They lower the heart rate and improve the blood supply to the myocardium. However, it is always necessary to start taking them with low doses. When the heart rate slows down to 55 beats per minute and below, the amount of the drug consumed must be immediately reduced;
- calcium channel blockers (Verapamil, Diltiazem) - I prescribe them if the patient has contraindications to taking beta-blockers (bronchial asthma, chronic broncho-obstructive pulmonary disease, AV block II and III degree);
- potassium-sparing diuretics (Spironolactone) - they are used in the development of chronic heart failure to remove excess fluid from the body;
- diuretics (torasemide, hydrochlorothiazide) I use it for severe symptoms of blood stasis: constant shortness of breath, pronounced swelling of the legs, accumulation of fluid in the chest and abdominal cavities;
- anticoagulants - many patients with HCM often develop atrial fibrillation, in which the risk of thrombosis and stroke is increased, so they need to take medications that thin the blood (Warfarin, Dabigatran, Rivaroxaban);
- antiarrhythmic drugs – almost all patients with HCM develop life-threatening rhythm disturbances, in order to control which they can be prescribed Disopyramide, Amiodarone, Sotalol.
In no case should vasodilators (drugs that cause vasodilatation) be used in patients with HCM. These include nitrates, AFP inhibitors, sartans, and calcium channel blockers: Amlodipine and Nifedipine. These medications cause reflex tachycardia, that is, they literally "make" the heart beat faster, which only aggravates the disease, so I try to avoid prescribing them.
There are patients who have a very high risk of sudden cardiac death - they have already had similar cases in their family, they faint and have severe rhythm disturbances on the ECG (frequent extrasystoles, persistent supraventricular and ventricular tachycardias, etc.). Such patients may be shown:
- implantation cardioverter defibrillator - Sewing a special device under the skin of the chest, capable of immediately arresting the arisen rhythm disturbance. It allows you to reduce the risk of death from arrhythmia to almost zero.;
- radio frequency catheter ablation – destruction by the laser of areas of pathological impulses.
