Systolic left ventricular dysfunction is relatively common in even asymptomatic alcoholics, but whether diastolic function is also altered is much less well-studied. We used M-mode and Doppler echocardiography to study left ventricular size, mass, systolic function and diastolic filling in 32 alcoholics free of clinically detectable heart disease and in 15 healthy control subjects. Left ventricular mass index and posterior wall thickness were higher in alcoholics than in controls, but there was no statistically significant difference either in end-diastolic size or in systolic ventricular function. More abnormalities were found in the Doppler indexes of diastolic function, however. The alcoholics had a prolonged relaxation time (200 +/- 6 vs 184 +/- 5 ms [mean +/- standard error], p less than 0.05), a decreased peak early diastolic velocity (52 +/- 2 vs 60 +/- 3 cm/s, p less than 0.05), a slower acceleration of the early flow (410 +/- 18 vs 552 +/- 43 cm/s2, p less than 0.01), and a higher atrial-to-early peak velocity ratio (0.74 +/- 0.04 vs 0.60 +/- 0.05, p less than 0.05). This pattern of changes suggests a primary abnormality in the relaxation of the left ventricle. In multivariate analyses, the abnormalities in the Doppler indexes were independent of the duration of alcoholism, the quantity of the most recent ethanol exposure and the increased mass of the left ventricle. Impaired early filling of the left ventricle due to delayed relaxation is common in asymptomatic alcoholics and may in fact be the earliest functional sign of preclinical alcoholic cardiomyopathy.