[Malignant familial cardiomyopathy with sudden death, typical asymmetric septal hypertrophy and dilated cardiomyopathy-like features].

Twenty-one members of a family were traced for three generations including the propositus, who had typical dilated cardiomyopathy (DCM)-like features. Clinical, radiological, electrocardiographic and echocardiographic examinations were performed for 13 of 16 still living. Five of 21 members died including three of sudden death. Among living 16 members, five had congestive heart failure, greater than grade III of the NYHA, and cardiomegaly on chest radiography in five. Left ventricular hypertrophy, abnormal Q waves, and ST-T changes were observed on electrocardiography in two, five and eight members, respectively. Echocardiography revealed asymmetric septal hypertrophy (ASH) in four, two of whom had systolic anterior motion (SAM) of the mitral valve. Two had features simulating DCM, and five had mitral valve prolapse. Among six patients with ASH or features simulating DCM, four had cardiac catheterization, coronary angiography and endomyocardial biopsy. None had significant coronary stenosis, but all had high left ventricular end-diastolic pressure (LVEDP) (23 +/- 7 mmHg). Endomyocardial biopsy showed moderate myocardial cellular hypertrophy, interstitial myocardial fibrosis, nuclear changes and myocardial disarrangement, with features characteristic of HCM. In this family with malignant HCM, patients had various clinical features including typical HCM, simulated DCM, DCM coexisted with mitral valve prolapse, and sudden death occurred frequently.