Dilated cardiomyopathy is one of the types of myocardial damage, which interferes with the contractile function of the heart through the expansion of the cavities of one or both ventricles. The disease may be accompanied by different rhythm disorders and heart failure. Basically, dilated (congestive) cardiopathology affects the left ventricle.
This defeat of myocardium is about 60% of all cardiomyopathies. The disease usually develops at the age from 20 to 50 years predominantly in men.
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Causes of dilated cardiomyopathy
Among the main reasons for this destruction of the heart muscle there are several theories:
Approximately 20 — 25% of cases of congestive cardiomyopathy is a manifestation of an inherited genetic disease syndrome Bart. The disease, in addition to myocardium, is characterized by lesions of the endocardium, other muscles of the body and retarded growth. About 30 % of patients with dilated heart disease systematically consume alcohol. Toxic effect of ethanol affects the proper functioning of the mitochondria of cardiomyocytes, causing the cell metabolic disorders.
Metabolic theory is insufficiency of such nutrients as selenium, carnitine, vitamin B1 and other proteins. Dilated cardiomyopathy may develop in some autoimmune disorders, which occur under the influence of that disease (at the moment, reason is not installed). In this case, the body produces specific antibodies to elements of the myocardium and damage heart muscle cells.
Scientific studies have proven the viral theory of the development of cardiomyopathy. Using diagnostic PCR (polymerase chain reaction-based DNA isolation of the virus) studied the damaging effect on the heart muscle cytomegalovirus, herpes virus, enterovirus and adenovirus. All these pathogens cause inflammation of the myocardium.
Sometimes in women after childbirth also can detect signs of dilated cardiomyopathy. In this case, is the place to be idiopathic variant of the disease (unmounted). It is considered that the main risk factors are:
- the age of mothers over 30 years;
- multiple pregnancy;
- the third and subsequent generations.
The mechanism of development of dilated cardiomyopathy
The pathogenic factor acts on the myocardium, causing a decrease in the number of full cardiomyocytes. This leads to the expansion chambers of the heart (mainly left ventricle), which is the main reason of violations of their functions. Ultimately develop congestive heart failure.
Initial stage of the disease almost invisible for the human body, because at this time, dilated cardiomyopathy kompensiruet protective mechanisms. Here there is an increase in heart rate and decrease vascular resistance for more free blood flow through it. When all the reserves of heart are depleted, the muscle layer of the heart becomes less stretchy and tighter. At the end of this stage begins to occur extension of the cavity of the left ventricle.
The next stage is characterized by insufficiency of the heart valves, because due to the increase in cavities they are stretched. At this stage, to compensate for the failure of myocardial cells increase in size (hypertrophied). For their nutrition becomes necessary a greater quantity of blood than usual. However, vessels are not changed and, accordingly, the circulation remains the same. This all leads to the malnutrition of the heart muscle and ischemia develops.
Further, because of progressive failure is disturbed the supply of blood to all organs of the body, including the kidneys. Their hypoxia (oxygen deprivation) activates the neural mechanisms that set the signal for contraction in all vessels. Because of this develop arrhythmias and increased blood pressure. In addition, more than half of the patients with dilated cardiomyopathy clots formed at the walls of the cavities of the heart and increases the risk of heart attacks and strokes.
The symptoms of dilated cardiomyopathy Development of symptoms is slow, so for a long time, the man has no complaints. The main symptoms in this disease are associated with the development of thromboses, heart rhythm disturbances and the emergence of heart failure.
In 10% of patients with dilated cardiomyopathy are marked anginal pain (pain in the heart, characteristic of angina pectoris). The vast majority of patients have fatigue, dry cough or shortness of breath. With the progression of heart failure with manifestations of stagnation in the systemic circulation appear swelling in the legs and pain right under the ribs.
Various disorders of heart rhythm cause fainting, bouts of dizziness and discomfort in chest and behind the breastbone. 10 – 30% of cases dilated cardiomyopathy occurs sudden death due to strokes, heart attacks and thromboembolism (obstruction of a blood clot) of the major arteries.
For this disease can be rapidly progressive and slow developing. In the first case nekompensirovanna-stage heart failure occurs after a year and a half since the emergence of pathology. The vast majority of variants dilated cardiomyopathy is characterized by slowly progressive changes of the internal organs.
Diagnosis of the disease
Timely identification of dilated cardiomyopathy is quite difficult due to the lack of absolute determinants of pathology. The final diagnosis based on evidence of increased heart chambers with exclusion of any other diseases that can cause the dilation.
Leading clinical manifestations of congestive cardiomyopathy:
- the increase in volume of the heart;
- the appearance of noise when working of the heart valves;
- shortness of breath;
- listen to stagnant rales in the lower lung.
For the final installation of the diagnosis using ECG diagnosis, Holter monitoring, echocardiography and other methods. The main changes that can be detected on the ECG in dilated cardiomyopathy:
- atrial fibrillation (afib) and other cardiac arrhythmias;
- conduction of a nerve impulse (AV-blockade and blockade of the beams gissa);
- change processes repolarization of the myocardium (reverse recovery of the initial electric potential).
When performing echocardiography detected extended cavity of the heart chambers and reduced ejection fraction of blood (reduced the amount of discarded blood into the vascular system while reducing myocardial). Sometimes defined parietal thrombi. X-ray study confirms the diagnosis by signs of increased pressure in the respiratory system of the body – pulmonary hypertension.
Treatment of dilated cardiomyopathy
Primary therapy is aimed at correcting the heart failure, arrhythmias, and the suppression of blood clotting. For this recommended bed rest and a diet with low content of salts and fluids.
The main groups of drugs used for the treatment of dilated cardiomyopathy:
- ACE inhibitors (enalapril, Perindopril, …);
- diuretics (Furosemide, Indapafon, Spironolactone, …);
- beta-blockers (Metoprolol, egilok, etc.);
- cardiac glycosides (Strofantin, Digoxin, …);
- nitrates prolonged (extended) action (Nitrosorbid, Trinitrolong, …);
- antiplatelet agents (Aspirin, Polcard, Cardiomagnyl, …);
- anticoagulants (subcutaneous administration of Heparin solution).
In severe disease, intractable to treatment, are transplant (transplant) heart. In this case, the survival rate is up to 85%.
The prognosis of the disease
The course and prognosis of the disease is mostly unfavorable. Only 20 – 30 % of patients live with this disease for over 10 years. Most patients die for the duration of cardiomyopathy from 4 to 7 years. Death occurs from congestive heart failure, embolism (overlap) of the pulmonary artery or the heart stops.
Prevention of dilated cardiomyopathy
The prevention of this disease is based on:
- medico-genetic counselling;
- timely treatment of respiratory viral and bacterial infections;
- the refusal of the use of alcohol in large quantities;
- a balanced diet.
Thus, we can conclude that dilated cardiomyopathy accompanied by expansion of the chambers of the heart that launches the cascade of irreversible reactions which lead to heart failure. With timely diagnosis and correct choice of treatment the risk of developing dangerous complications can be reduced and a time to delay.