Cardiomyopathies in children

Cardiomyopathies are a heterogeneous group of chronic, severe myocardial diseases leading to the development of myocardial dysfunction.

The term "cardiomyopathy" was first proposed by W. Brigden (1957) to define myocardial diseases of unknown origin. At present, this concept cannot be considered clearly defined; it is often given different meanings. In the modern nomenclature of diseases (WHO, 1996), idiopathic (of unclear or unknown etiology), specific (in various diseases associated with damage to other organs, or with a known etiology) cardiomyopathies and unclassifiable myocardial diseases are distinguished.

Classification

The following classification of cardiomyopathy was approved by WHO in 1996.

1. Idiopathic cardiomyopathy (of unknown genesis).
2. Specific cardiomyopathies.
   1. Inflammatory cardiomyopathies:
      • infectious;
      • autoimmune.
   2. Ischemic cardiomyopathy is a diffuse disorder of myocardial contractility with pronounced changes in the coronary arteries.
   3. Hypertensive cardiomyopathy - with left ventricular hypertrophy due to arterial hypertension in combination with signs of dilated or restrictive cardiomyopathy.
   4. Metabolic cardiomyopathies:
      • endocrine (in acromegaly, hypocorticism, thyrotoxicosis, myxedema, obesity, diabetes mellitus, pheochromocytoma);
      • in infiltrative and granulomatous processes, storage diseases (amyloidosis, hemochromatosis, sarcoidosis, leukemia, mucopolysaccharidosis, glycogenosis - Pompe disease), lipidosis (Gaucher disease, Fabry disease);
      • in case of deficiency of microelements (potassium, magnesium, selenium, etc.), vitamins and nutrients (beriberi, kwashiorkor), as well as in case of anemia.
   5. Cardiomyopathy in systemic connective tissue diseases (dermatomyositis, rheumatoid arthritis, systemic scleroderma, systemic lupus erythematosus).
   6. Cardiomyopathy in systemic neuromuscular diseases:
      • neuromuscular disorders (Friedreich's ataxia, Noonan syndrome);
      • muscular dystrophies (Duchenne, Becker, myotonia).
   7. Cardiomyopathy caused by exposure to toxic and physical factors (alcohol, cobalt, lead, phosphorus, mercury, anthracycline antibiotics, cyclophosphamide, uremia, ionizing radiation).
3. Unclassifiable cardiomyopathies (endomyocardial fibroelastosis, noncompact myocardium, mitochondrial diseases, minimal dilation systolic dysfunction).

Currently, the clinical classification of cardiomyopathies (WHO, 1980, modified taking into account the data of WHO, 1995), constructed taking into account the leading pathophysiological mechanisms, has received general recognition.

Pathophysiological classification of cardiomyopathies (WHO, 1995).

• Dilated cardiomyopathy (DCM). Characterized by dilation and impaired contractility of the myocardium of the left or both ventricles.
• Hypertrophic cardiomyopathy (HCM). The typical symptom is hypertrophy of the myocardium of the left and/or right ventricle of the heart with preserved contractile and impaired diastolic function; two forms are distinguished:
  • with obstruction;
  • without obstruction.
• Restrictive cardiomyopathy (RCM). Characterized by dilation of the atria and impaired diastolic filling of the ventricles; three forms are distinguished:
  • primary myocardial;
  • endomyocardial with eosinophilia;
  • endomyocardial without eosinophilia.
• Arrhythmogenic right ventricular cardiomyopathy (ARVC). Characterized by progressive replacement of the myocardium of the right and/or left ventricle with fibro-fatty tissue, leading to severe arrhythmias and sudden death.

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