Cardiomyopathy restrictiveI42.5

Very rare form of cardiomyopathy with reduction of diastolic stretch and function (restriction) especially of the left ventricle, more rarely also of the right ventricle. This leads to an impairment of the filling of one or both ventricles. In restrictive cardiomyopathy (RCM) the heart is usually not dilated and not hypertrophied. Exception: restrictive cardiomyopathy due to systemic amyloidosis and Fabry's disease. In advanced cases the endocardium is thickened with a tendency to form thrombosis and an increased tendency to embolism.

Classification of restrictive cardiomyopathies (RCM):

Myocardial restrictive cardiomyopathy

• Non-infiltrative restrictive cardiomyopathy
  • Idiopathic RCM
  • Familial RCM: desminopathies, sarcomeric protein mutations, mutations in the genes TNNT2 and TNNI3; Pseudoxanthoma elasticum (Peled Y et al. 2014; Hayashi T et al. 2018)
• RCM in systemic scleroderma
• restrictive infiltrative cardiomyopathy
  • RCM in storage diseases (hemochromatosis, Fabry disease, glycogen storage diseases)
  • RCM in systemic amyloidosis, sarcoidosis, Gaucher disease, Hurler syndrome

Endomyocardials RCM

• Endomyocardial fibrosis (tropical form occurring in Africa; hypereosinophilia syndrome (see also eosinophilic fibroblastic endocarditis Löffler) with medication: serotonin, ergotamine, busulfan)
• Carcinoid (endocardial fibrosis, especially of the right ventricle (Hedinger syndrome)

In Europe, restrictive cardiomyopathy is less common than dilated and hypertrophic cardiomyopathy. In tropical countries significantly more common due to the high incidence of endomyocardial fibrosis in these countries. 14% of patients who died of heart disease in Uganda and 10% in Nigeria suffered from RCM.

RCM is very rare in children under 15 years of age.

Endocardial fibrosis is the most common cause of RCM. Eosinophils seem to play an important pathogenetic role. Furthermore, infections like toxoplasmosis, rheumatic fever, exposure to cerium (rare earth) play a role in the development of endomyocardial fibrosis. Various mutations play a role in non-infiltrative RCMs.

The signs of right heart failure predominate. Signs of dyspnea, fatigue, less frequently pectanginous complaints as well as symptoms of systemic thromboembolism, leg edema, pericardial effusions, ascites, pulmonary congestion. The heart may be of normal size or slightly enlarged and the ventricular cavity may be both dilated and reduced. The atria are dilated.

Macroscopic evaluation of the myocardium: myocardial rigidity, significantly thickened endocardium, most frequently affecting the influential tract, parts of the outflow tract and the apex of the heart. The left ventricular endocardial thickening usually ends abruptly at the anterior mitral sail. In case of progression, the apex of the heart is drawn to the AV valve plane. This leads to a partial ventricular obliteration. Parietal thrombi are often located in the ventricle. The organization of these thrombi leads to endocardial fibrosis.

Doppler echocardiography: enlarged atria, normal-sized ventricles; evidence of a restrictive filling pattern; in the late stage, restriction of pumping function.

Laboratory: important indications of an underlying disease (e.g. sarcoidosis, amyloidosis, hemochromatosis; carcinoid; Fabry's disease; hypereosinophilia)

X-ray/CT/MRI

Invasive diagnostics, if necessary with endomyocardial biopsy: Histologically, the stratification of the thickened endocardium is characteristic for endomyocardial fibrosis (EMF) and endocarditis parietalis fibroplastica (EPF). Beneath the endocardial layer where thrombi may lie is a zone of granulation tissue consisting of loose connective tissue with dilated vessels and interspersed inflammatory cells and occasionally eosinophilic cells. Both calcification and ossification of these altered structures can occur. The myocardial fibres may be hypertrophic; they are surrounded to varying degrees by inflammatory infiltrates and fibrosis. A pericardial thickening due to unspecific fibrous tissue is not uncommon.

Therapy of an existing underlying disease

Therapy of heart failure (early with diuretics)

For terminal heart failure - heart transplantation

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