FREQUENCY AND PHENOTYPES OF FAMILIAL DILATED CARDIOMYOPATHY

Objectives, This prospective study was performed to analyze the freque ncy and clinical characteristics of idiopathic dilated cardiomyopathy (DCM). Background. Despite several previous reports on families with D CM, most cases are still believed to be sporadic, and specific clinica l findings of the familial form are not well defined. Methods. In 345 consecutive patients with angiographically proven DCM, we obtained det ailed family histories to construct pedigrees and examined 970 first-a nd second-degree family members. Results. Familial DCM was confirmed i n 48 (10.8%) of the 445 index patients and was suspected in 108 (24.2% ). The 156 patients with suspected or confirmed familial disease were younger at the time of diagnosis (p < 0.03) and more often revealed el ectrocardiographic changes (p = 0.0003) than patients with nonfamilial disease, Among the families of the 48 index patients with confirmed f amilial disease, five phenotypes of familial DCM could be identified: 1) DCM with muscular dystrophy; 2) juvenile DCM with a rapid progressi ve course in male relatives without muscu lar dystrophy; 3) DCM with s egmental hypokinesia of the left ventricle; 4) DCM with conduction def ects; and 5) DCM with sensorineural hearing loss. Conclusions. Up to 3 5% of patients with DCM may have an inherited disorder, Distinct clini cal phenotypes can be observed in some families, suggesting a common m olecular cause of the disease. (C) 1998 by the American College of Car diology.