Echocardiographic Evaluation in Asymptomatic Relatives of Patients with Dilated Cardiomyopathy Reveals Preclinical Disease.

Background: Idiopathic dilated cardiomyopathy is often familial, and apparently healthy relatives may have latent early, or undiagnosed established disease. Objective: To determine the prevalence and natural history of asymptomatic cardiac abnormalities among sampled relatives of unselected patients referred for management of dilated cardiomyopathy. Design: Prospective cohort study. Patients: 767 asymptomatic relatives of 189 consecutive unselected patients with dilated cardiomyopathy. Measurements: Clinical evaluation, including history, physical examination, electrocardiography, and echocardiography, was per- formed. Participants were classified in accordance with published echocardiographic criteria. Sampled relatives who did not have evidence of dilated cardiomyopathy at the initial evaluation were followed for a median of 57 months (range, I to 133 months). Results: Of the 767 patients evaluated, 592 (77.2%) were assessed as healthy, 35 (4.6% [95% CI, 3.7% to 7.6%]) had dilated cardiomyopathy, 119 (15.5% [CI, 12.5% to 18.8%]) had left ventricular enlargement without systolic dysfunction, and 21 (2.7% [CI, 1.9% to 4.9%]) had depressed fractional shortening without ventricular dilatation. At follow-up, progression to dilated cardiomyopathy occurred in 13 (10%) relatives with left ventricular enlargement or depressed fractional shortening versus 3 (1.3%) healthy relatives. In a multivariate model, only left ventricular enlargement or depressed fractional shortening independently predicted progression to dilated cardiomyopathy (hazard ratio, 10.0 [CI, 2.8 to 35.5]; P<0.001). Limitations: Because relatives had to be willing to participate and be available geographically, selection bias may have occurred. Conclusion: Treatable asymptomatic dilated cardiomyopathy was identified in 4.6% of asymptomatic relatives. In addition, left ventricular enlargement and depressed fractional shortening were common in asymptomatic relatives of patients with dilated cardiomyopathy and were associated with a statistically significant medium-term risk for disease progression. Evaluation of relatives of patients with cardiomyopathy is recommended. [ABSTRACT FROM AUTHOR]