Familial cardiomyopathy A review of 11 families

Findings in 11 families with cardiomyopathy are reviewed. Of 98 persons examined, 47 were affected. Their mean age at the time of detection was 24 years (range 2 to 61 years). The diagnosis was made by exclusion. The presence of other affected members, often in 2 or 3 generations of the same family, enabled us to establish the familial character.

The clinical findings included palpitations, arrhythmias, syncope and sudden death. Nine patients had intractable congestive heart failure, and 6 Stokes-Adams attacks; 4 of the 6 had implanted pacemakers. Several patients had proved or suspected hypertrophic subaortic stenosis.

The electrocardiogram proved to be the best single tool for the detection of cardiomyopathy. Rhythm disturbances, left ventricular hypertrophy, intraventricular conduction defects and abnormal Q waves were frequent. The Wolff-Parkinson-White pattern was found in 4 patients. Clinically the diagnosis of mitral valve disease and myocardial infarction was often considered.

The prognosis is uncertain; when first detected 28 patients were asymptomatic, and only 13 have remained asymptomatic during a follow-up period of 7 years. Ten of the 47 patients died during this period, and in the 9 who came to autopsy, no congenital, rheumatic, infectious or coronary heart disease was found. The hearts were enlarged, and histologie examination revealed diffuse fibrosis with severe hypertrophy of the muscle fibers.

Of special interest were the dynamic changes in the electrocardiogram with the disappearance of the abnormal Q waves and infarctionlike patterns with advancing age, as well as appearance of left bundle branch block. Serum enzyme disturbances were detected in some families, and their possible significance is discussed.

Genetically, the findings are consistent with transmission by an autosomal dominant gene with high penetrance.