Frequency of asymptomatic disease among family members with noncompaction cardiomyopathy.

Noncompaction cardiomyopathy (NCC) is a primary cardiomyopathy characterized by an excessively prominent trabecular meshwork and deep intertrabecular recesses of the left ventricular walls. Most cases are inherited, with a dominant inheritance pattern. The aim of the present study was to determine the prevalence and clinical characteristics of cardiomyopathies in the close relatives of patients with NCC. We evaluated 156, mostly first-degree, family members of 44 adult patients with NCC who agreed to familial screening. A family history of cardiac disease was reported by 16 (36%) of the 44 patients, including premature sudden death in 8 families (18%). NCC (n = 32) or dilated cardiomyopathy (n = 9) was diagnosed in 41 relatives (26%) by echocardiography (n = 25), contrast echocardiography (n = 6), or magnetic resonance imaging (n = 10). Of these family members, 13 already had known cardiac symptoms and signs, but most (28 of 41) were asymptomatic. Most subjects with NCC had mild to moderate left ventricular dysfunction (n = 29, 71%). After a median follow-up of 55 months (interquartile range 43 to 93), most remained asymptomatic. Four family members were treated with prophylactic implantable cardioverter-defibrillator placement and 23 of those with NCC were treated with drugs, including angiotensin-converting enzyme inhibitors (41%), β blockers (34%), and anticoagulants (17%). In conclusion, there is a high prevalence, mostly asymptomatic, of cardiac disease (26%) among first- and second-degree family members of patients with NCC. This warrants screening and offers an opportunity for early intervention.