Dilated cardiomyopathy
The content of the article:
- Causes and risk factors
- Disease types
- Symptoms
- Diagnostics
- Treatment
- Possible complications and consequences
- Forecast
- Prevention
Dilated cardiomyopathy (DCM) is a structural and functional change in the myocardium (not associated with primary valvular defects, hypertension or pathology of the arteries supplying the heart tissue), manifested by stretching of the heart chambers, dilatation (from the Latin dilato - "to expand").
Sign of dilated cardiomyopathy
The disease is widespread and is the most common cardiomyopathy, accounting for 6 out of 10 reported cases of pathology. The incidence, according to various sources, is from 2 to 7 people per 100,000 per year. A large proportion of patients are young and mature men (ratio 5-6: 1). The diagnosis of DCM is often an indication for heart transplantation, which is associated with progressive heart failure complicating the disease.
The pathogenesis of dilated cardiomyopathy is due to a decrease in the number of fully functioning cardiomyocytes (cells of the muscle layer of the heart), which leads to a decrease in myocardial contractility. As the compensatory mechanisms are depleted, the chambers of the heart are overstretched, and blood stagnation is formed, including in the supplying vessels and, later, in the circulation.
Violation of the blood supply to organs and tissues provokes hyperactivation of the renin-angiotensin-aldosterone system (it controls blood pressure and circulating blood volume), an increase in the concentration of adrenaline and norepinephrine in the blood plasma. Biologically active substances have a stimulating effect on the damaged cardiovascular system, thereby aggravating pathological changes, which determines the severity of the disease.
Synonym: congestive cardiomyopathy.
Causes and risk factors
A wide range of causative factors of dilated cardiomyopathy, specific to specific forms of the disease, are known:
- genetic predisposition (inheritance in an autosomal dominant or autosomal recessive manner), is a presumptive cause of the pathology in 25–40% of patients;
- infectious lesion of the myocardium, myocarditis (provoked by fungi, bacteria, viruses, protozoa), leading to damage to the cells of the heart muscle;
- autoimmune diseases;
- immuno-inflammatory damage to the connective tissue;
- intoxication (both acute and chronic);
- endocrinopathies;
- pregnancy (hemodynamic adjustment);
- metabolic diseases;
- fasting (deficiency of tryptophan, thiamine, selenium, protein starvation).
Myocardial infection can lead to the development of dilated cardiomyopathy
Since only a small proportion of patients exposed to the isolated effects of the above factors develop cardiomyopathy, some researchers talk about the polyetiology of the disease. This statement implies that the development of pathology is provoked by a combination of several causal factors, more often against the background of a hereditary predisposition.
The most common cause of dilated cardiomyopathy in clinical practice is chronic alcohol intoxication, which is explained by the direct damaging effect of ethyl alcohol and its decay products (in particular, acetaldehyde) on the myocardium (the cardiodepressive effect of alcohol). Other toxic agents include cobalt, cadmium, anticancer drugs, pesticides, heavy metal salts, petroleum products, paints and varnishes, etc.
Disease types
Depending on the etiology, several types of dilated cardiomyopathy are distinguished:
- idiopathic (primary) DCPM. The causal factor in this case cannot be established;
- genetically determined;
- viral;
- autoimmune;
- alcoholic or other toxic;
- associated with systemic diseases, in which the degree of myocardial damage does not correspond to the degree of its hemodynamic overload.
Symptoms
In the vast majority of cases of dilated cardiomyopathy, all painful manifestations can be attributed to one of the following symptom complexes: symptoms of chronic heart failure, thromboembolism, rhythm disturbances.
As a rule, the disease debuts gradually, with nonspecific complaints, less often - subacutely, against the background of any provocation (intoxication, infectious process, pregnancy and childbirth, etc.):
- decreased exercise tolerance;
- unsatisfactory general health, asthenization;
- shortness of breath on exertion;
- palpitations, a feeling of "sinking" of the heart.
Palpitations, shortness of breath on exertion, deterioration in general health are the main complaints in dilated cardiomyopathy
A mild onset of the disease is associated with extensive compensatory capabilities of the cardiovascular system, while extensive clinical manifestations indicate a breakdown in compensation:
- edema of the lower extremities, which tends to spread from the legs and feet upward as the process progresses;
- shortness of breath with light exertion or at rest;
- pallor or cyanotic coloration of the skin and visible mucous membranes;
- heaviness and a feeling of fullness in the right hypochondrium;
- systematic interruptions in the work of the heart;
- tachycardia;
- arrhythmic pulse;
- increased fatigue;
- pains in the region of the heart of various nature (stitching, pressing, burning, sometimes - a feeling of vague discomfort in the chest);
- thromboembolism of vessels of various caliber and localization.
Objectively, patients have additional III and IV tones, systolic murmur of mitral regurgitation, signs of stagnation in the small and large circles of blood circulation, cardiac arrhythmias.
In the majority of patients, in the absence of timely diagnosis and therapy within 5 years, circulatory disorders become intense, life-threatening.
Diagnostics
The diagnosis is made based on the results of the following studies:
- ECG (ventricular arrhythmias, low voltage of QRS complexes in the leads from the extremities and high-amplitude R and S in the chest leads, depression of the ST segment, T wave inversion);
- chest x-ray (enlargement of the "left heart" or all of its parts);
- Ultrasound of the heart (expansion of cavities, a decrease in the ejection fraction and an increase in the end diastolic size of the left ventricle, deformation and functional failure of the valve apparatus, intra-atrial and intraventricular thrombosis);
- stress tests (decreased stress tolerance).
ECG and ultrasound of the heart are the main diagnostic methods for dilated cardiomyopathy
Treatment
Since the bulk of the symptoms of the disease is due to the development of heart failure, the main treatment is aimed at stopping its manifestations:
- lifestyle modification;
- diuretic drugs;
- cardiac glycosides;
- angiotensin-converting enzyme (ACE) inhibitors;
- β-blockers;
- calcium antagonists (slow calcium channel blockers);
- nitrates;
- adrenergic receptor stimulants;
- phosphodiesterase III inhibitors;
- antiplatelet agents;
- indirect anticoagulants;
- glucocorticosteroid hormones.
In case of ineffectiveness of therapeutic methods of treatment, heart transplantation is indicated.
Possible complications and consequences
Complications of dilated cardiomyopathy are extremely serious:
- thromboembolism (including life-threatening);
- ventricular fibrillation;
- sudden cardiac death;
- progression of heart failure.
Forecast
The prognosis is poor. The mortality rate of patients with dilated cardiomyopathy is 10% per year, the five-year survival rate is 50%, and the ten-year survival rate is from 15 to 30%. In the presence of heart failure corresponding to functional class IV, the probability of death within a year is 50%.
Prevention
Preventive measures are as follows:
- Compliance with dietary recommendations (a complete diet with a sufficient amount of vitamins, trace elements, with fluid and salt restriction).
- Dosed physical activity.
- Refusal from alcohol abuse, smoking.
- Weight loss - if you are overweight.
- Regular preventive examinations with instrumental examinations, stress tests.
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Olesya Smolnyakova Therapy, clinical pharmacology and pharmacotherapy About the author
Education: higher, 2004 (GOU VPO "Kursk State Medical University"), specialty "General Medicine", qualification "Doctor". 2008-2012 - Postgraduate student of the Department of Clinical Pharmacology, KSMU, Candidate of Medical Sciences (2013, specialty "Pharmacology, Clinical Pharmacology"). 2014-2015 - professional retraining, specialty "Management in education", FSBEI HPE "KSU".
The information is generalized and provided for informational purposes only. At the first sign of illness, see your doctor. Self-medication is hazardous to health!
