Cardiomyopathy

Cardiomyopathy is a complex of non-inflammatory cardiac diseases that affect the heart muscle. The term "cardiomyopathy" comes from three Greek words - kardia, which means heart, myos - muscle and pathos - pathology, disease. The etiology of this symptom complex is still unclear, but it has been established that the disease is not provoked by hypertension, ischemic heart disease (CHD), and has nothing to do with heart defects. All the changes observed in CMP can provoke quite serious pathological disorders in the work of the myocardium, which is responsible for the normal heart rhythm. The rhythm of contractions is based on the structural features of the myocardial muscle tissue, dystrophic, sclerotic lesions can lead to heart failure, arrhythmia and other cardiopathologies.

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Cardiomyopathy: history of disease development and classification

Terminology of cardiomyopathy was formalized not so long ago. In the middle of the last century, in the 60s, cardiologist Bridgen conducted a study of heart diseases of unclear etiology. All cardiac pathologies that were studied were characterized by an increase in the heart muscle, a decrease in blood circulation activity and fatal outcomes. Clinical cases were not related to coronary heart disease, rheumatism, hypertension or cardiac defects. Thus, Bridgen was the first to suggest calling such myocardial pathologies cardiomyopathies. Only in 1995, the disease "cardiomyopathy" received a clear definition, and a standard classification of CMP was also developed. Specific cardiomyopathies of the stage are called all myocardial dysfunctions of a specific etiology (ischemic cardiomyopathy, metabolic, hypertensive and other forms). If the etiology of the disease is unclear, then cardiomyopathy is classified as primary. In addition, WHO (World Health Organization) proposed uniform forms of the disease that correspond to the pathophysiology and pathological anatomical specificity of the development of the disease:

• Dilated - the cavity of the left ventricle of the heart increases, the ability to contract the muscle is noticeably reduced (decreased systole). It is the most common.
• Hypertrophic – the walls of the left ventricle thicken significantly and grow, and, accordingly, the relaxation function (diastolic) decreases.
• Arrhythmogenic (subventricular) – a change in the structure of the right ventricle (less often the left), fibrous-fatty degeneration of myocardial tissue. It is rare or diagnosed as a subtype.
• Restrictive – the elasticity of the myocardial walls decreases due to fibrous degeneration, infiltrates, and, accordingly, the relaxation function decreases. This form is less common than others, but there is information that RCM is not accurately diagnosed due to the similarity of symptoms with other diseases or due to insufficient study.
• Unclassified cardiomyopathy - pathologies that cannot be classified into any specific group based on specificity. This variant has been practically unstudied.

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Cardiomyopathy: description of disease forms

Dilated cardiomyopathy is the most common type of the disease, accounting for more than 60% of all diagnosed cases of cardiomyopathy. Dilation (from the Latin dilato – to expand) leads to pathological dysfunction of myocardial contraction due to expansion of the cavities (chambers). Dilated cardiomyopathy is often called "congestive". As a rule, DCM is diagnosed as a pathology of the left ventricle of the heart, less often the right ventricle is affected. The tissue walls remain unchanged, thickening or fibrous degeneration is not observed. Most often, dilated cardiomyopathy is a genetically determined disease, also among the factors provoking the dilated form of cardiomyopathy are infectious, autoimmune diseases, intoxication, including alcohol, dystrophic muscle pathologies.

DCM is diagnosed using a comprehensive examination, which necessarily includes an electrocardiogram, ultrasound of the heart, and an X-ray. Also important for clarifying the diagnosis are anamnestic information and laboratory tests of blood serum. The main diagnostic method confirming the dilated form of the disease is an ultrasound examination, all other diagnostic measures are not considered specific, rather they help to build a therapeutic strategy.

The clinical manifestations of dilated cardiomyopathy are very similar to the symptoms of heart failure. Typical signs are shortness of breath with little exertion, swelling, decreased general activity, pallor and cyanosis (acrocyanosis) of the skin, especially cyanosis of the fingertips. Arrhythmia, atrial fibrillation, progressive cardialgia can lead to thromboembolism and even death. The prognosis of this disease is unfavorable, since even with proper drug treatment, the mortality rate is about 40%, if dilated cardiomyopathy is diagnosed late, the mortality rate is 65-70%. DCM and pregnancy are incompatible, since the percentage of fatal outcomes in these cases is almost 90%.

Therapeutic measures primarily solve the compensatory problem: it is necessary to ensure the rhythm of heart contractions and minimize the manifestations of heart failure. Prevention of possible serious complications is also important. The prescription of ACE (angiotensin-converting enzyme) inhibitors is indicated - enalapril, enap, captopril, berlipril. Cardioselective beta-blockers are also effective - timolol, metoprolol, diuretics and anticoagulants - angiox, verfarin, fraxiparin. Acute conditions of the disease are treated with medication in hospital settings, in cases of exacerbation, surgical intervention is possible up to organ transplantation.

The hypertrophic form of cardiomyopathy is characterized by a pathological enlargement (thickening) of the walls of the left ventricle without noticeable dilation of the cavity. Thus, the normal diastolic activity of the muscle is disrupted, the ventricle becomes denser, poorly stretched, causing increased intracardiac pressure. Among the causes of HCM, there is also a family predisposition, which manifests itself in pathological gene defects that cannot cope with the synthesis of myocardial protein compounds. Hypertrophic cardiomyopathy can be congenital, but most often it is diagnosed in puberty, when the symptoms become obvious.

Hypertrophic cardiomyopathy is quickly identified and differentiated from other forms. Diagnosis is based on the symptoms presented, anamnestic information (including family information). Stethoscopic listening clearly identifies systolic murmurs. The main method that specifies the form of cardiomyopathy is ultrasound examination, ECG information is also important, where changes in rhythm and conductivity are visible. An X-ray usually shows increased intracardiac pressure in the left branch of the pulmonary trunk (artery).

The clinical manifestations that are characteristic of hypertrophic cardiomyopathy are rapidly progressing symptoms of heart failure. Cardialgia, frequent dizziness up to fainting, edema and dyspnea. Extrasystolic disorders, tachycardia (paroxysms), endocarditis and thromboembolism often develop. These signs, unfortunately, appear already at the stage of the developed disease, while the onset of cardiomyopathy is most often asymptomatic. This explains sudden deaths in fairly young people who do not have visible cardiac pathologies, sudden death is especially characteristic of people involved in sports with strong physical overloads.

Therapeutic actions in diagnosed HCM are aimed at compensating the work of the left side of the heart, eliminating the insufficiency of functioning. Cardiomyopathy of the hypertrophic form is controlled by the use of active beta-blockers, such as verapamil, isoptin, finoptin. Also effective are cardiotonics - glycosides, such as strophanthin, corglycon, rauwolfia alkaloids as antiarrhythmic agents - rimodan, rhythmilen, diuretics. In the acute form of the disease, electrical cardiac stimulation and surgical intervention are indicated.

Restrictive variant of cardiomyopathy. This type of CMP is rarely diagnosed, possibly due to the poor study of the disease and the asymptomatic course of the disease. With this form of the disease, the relaxation of the myocardial muscles is impaired, contraction is reduced, the muscle becomes rigid due to fibrous degeneration of the inner wall (endocardium). This leads to insufficient filling of the left side of the heart (ventricle) with blood flow. The tissue of the ventricular walls does not structurally change, it is not thickened, and expansion of the cavity is not detected. If HCM is accompanied by serious pathologies, such as lymphoma, hemochromatosis (pathological accumulation of iron in tissues), the symptoms become more obvious, and the development of the disease is rapid.

The restrictive form of cardiomyopathy is diagnosed similarly to other forms of cardiomyopathy. The main indicative method is ultrasound scanning of the heart, as well as angiocardiography. X-ray shows a significant increase in the size of the atria, although the heart itself does not change either shape or size. An electrocardiogram is not informative for this form of cardiomyopathy, laboratory tests of blood serum are additional and necessary for choosing drugs, but not indicative in a diagnostic sense.

Restrictive cardiomyopathy most often occurs without obvious signs. Symptoms appear in the last stage of the disease, or in combination with other pathologies. Among the obvious symptoms, the following can be distinguished:

• Shortness of breath with little physical exertion;
• Frequent sore throats;
• Nocturnal paroxysmal attacks of dyspnea;
• Edema;
• Ascites.

Cardiomyopathy of this form is difficult to treat, the therapeutic strategy is mainly aimed at eliminating acute pathological symptoms, the next stage of treatment is extremely unpredictable. Restrictive cardiomyopathy is asymptomatic, and treatment begins at the last terminal stage, when drug therapy is practically powerless. Basic therapy solves the following problems:

• Minimizing pulmonary overload;
• Decrease in intracardiac pressure;
• Activation of systolic function (pumping);
• Minimizing the risk of blood flow obstruction - thromboembolism.

The prognosis for this form of cardiomyopathy is very unfavorable, statistics show that about 50% of patients die within two to three years after diagnosis. Restrictive cardiomyopathy progresses rapidly, diastolic dysfunction develops rapidly. Cardioglycosides, vasodilators, and diuretics are indicated. Timely drug therapy can prolong the life of patients for several years, and endocardectomy or valve replacement also alleviates the condition. However, surgical intervention is associated with an objective risk of increased mortality.

Cardiomyopathy is dangerous in all forms and stages, so early diagnosis plays an important role in the effectiveness of treatment and its outcome. In cases where heart failure cannot be controlled with therapeutic measures, a heart transplant is performed.

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