Clinico-pathological evaluation of restrictive cardiomyopathy (endomyocardial fibrosis and idiopathic restrictive cardiomyopathy) in India.

BACKGROUND: Restrictive heart disease is characterized by impairment of ventricular filling during diastole with preserved systolic function. The clinical and histopathological profile on endomyocardial biopsy of a cohort of patients with restrictive cardiomyopathy (RCM) is presented.

METHODOLOGY: The medical records of patients presenting with heart failure with systemic congestion, subsequently diagnosed as restrictive heart disease after evaluation including cardiac catheterisation, were studied retrospectively to determine the clinical spectrum of restrictive cardiomyopathy. The diagnosis of RCM was made, based on systemic congestion with dilated atria and near normal ventricular size and function. Only patients who had an endomyocardial biopsy were included in the study. Patients with chronic constrictive pericarditis and secondary restrictive heart disease mainly amyloidosis were excluded from the study.

RESULTS: All 52 patients had heart failure with normal or near normal left ventricular size and function. Based on right and left ventricle angiography, patients were classified into two groups. Group I with findings suggestive of EMF (n=30) and Group II no evidence of EMF on angiography i.e. 'idiopathic RCM' (IRCM) (n=22). Baseline characteristics were similar in the two groups. Echocardiography revealed typical features of endomyocardial fibrosis in Group I patients, with apical obliteration of right and left ventricular apices. Group II patients had no apex obliteration (except in four patients, who were misclassified and in whom angiography did not show apex obliteration). The Group II patients had features of IRCM in the form of normal left and right ventricular size and function with restrictive features of doppler filling along with dilated left and right atria. Angiocardiography in EMF patients showed isolated RV involvement in only two patients. In the remaining 28 patients, the obliterative changes were biventricular with RV involvement more severe than LV involvement. Angiographic findings in Group II (IRCM) patients were unremarkable with preservation of normal trabecular pattern and absence of obliterative changes. Mild atrioventricular regurgitation was present in 10/22 patients. Histopathological examination revealed that endocardial thickening was more common (77% vs. 23%) in EMF patients. The presence of myocyte hypertrophy (70-80%), myocytolysis (40-50%) and interstitial fibrosis (46-56%) were similar in both groups.

CONCLUSIONS: The majority of our patients had biventricular EMF. A significant number of patients had clinical hemodynamic features of restrictive heart disease but no evidence of EMF on angiography. These IRCM patients had similar clinical profiles to EMF but on endomyocardial biopsy the endocardial thickening was minimal and seen in few patients (5/22).