Familial cardiomyopathy--a 15-year follow-up.

In 1961--1962 five families including 53 members with a familial form of cardiomyopathy (CMP) were examined. Fifteen years later a reinvestigation of the previously examined families was carried out using community registers; mortality as well as new family members were registered. Another 50 family members were thereby added. Three out of 6 young subjects who were diagnosed as having definite (2) or suspected (1) CMP at the initial examination died during the follow-up period. Four of the five families, totalling 39/41 members, were given a thorough noninvasive clinical examination including ECG, phonocardiogram exercise test, measurement of systolic time intervals and carotid arterial pulse curves, and echocardiography (Echo). A high number (17/39) of suspected or definite pathologic echocardiographic changes consistent with CMP was observed on reinvestigation. Eleven of these 17 were asymptomatic. Except for Echo, the non-invasive methods used in this study did not contribute to the diagnosis of CMP, but the non-Echo methods confirmed the Echo findings in those patients with symptoms of cardiac disease. The four reexamined families revealed a very heterogenous pattern of CMP, with both symmetric and asymmetric hypertrophy (ratio symmetric/asymmetric = 15 : 2). It may be questioned whether asymptomatic subjects with borderline changes, indicative of symmetric hypertrophy, will develop definite symmetric CMP or whether their symptoms constitute an early stage of asymmetric CMP. Echocardiographic findings may well fit with the theory of a dominant mode of inheritance.