We compared brain magnetic resonance imaging and neuropsychologic performance in 20 neurologically asymptomatic patients suffering from idiopathic dilated cardiomyopathy (mean age 41 [range 18-49] years) and 20 age-matched controls (mean age 38 [range 28-49] years). Patients exhibited a significantly higher rate of cerebral infarcts (20% versus 0%, p less than 0.05) and cortical (50% versus 5%, p less than 0.01) and ventricular (55% versus 15%, p less than 0.02) atrophy than controls. Accordingly, semiquantitative volumetric measurements yielded a significantly increased ventricular-to-intracranial cavity ratio in the patients (6.2 +/- 2.9% versus 4.1 +/- 1.3%, p less than 0.01). This ratio and the cortical atrophy ratings correlated positively with disease duration (r = 0.63 and 0.54, p less than 0.05). Cognitive test performance was significantly worse in patients than in controls and was most impaired in those patients with morphologic cerebral abnormalities.