Various types of cardiovascular complications, such as myocardial infarction, cardiac arrhythmias, cardiomyopathy, and myocarditis attributed to interferon therapy have been reported. The aim of this study was to evaluate the cardiac effects of interferon-alpha (IFN-alpha) in patients with chronic hepatitis B infection. Forty-five patients with chronic hepatitis B infection ( 41 men and 3 women; mean age 34.2 +/- 11.5 years) were included in the study, and 10 MU IFN-alpha 2b was administered three times a week for 6 months to the patients. Cardiac evaluation ( detailed medical history, physical examination, electrocardiography, systolic and diastolic function parameters by echocardiography) was performed at the beginning, and at the 1st, 3rd, and 6th months of therapy. No patients had any cardiac symptoms during interferon therapy, and systolic and diastolic blood pressure and heart rate were not significantly affected ( P > 0.05). None of the patients revealed cardiac rhythm disturbance on electrocardiography before or during the therapy period. No significant changes were detected in systolic ( ejection fraction, fractional shortening, pre-ejection period, left ventricular ejection time, the ratio of pre-ejection period/ejection time, Q-V peak) and diastolic ( E peak, A peak of transmitral flow velocity, E/A ratio, deceleration time, isovolumic relaxation time by conventional echocardiography, and E peak, A peak, deceleration time of E wave at the medial and lateral corners of the mitral annulus by tissue Doppler echocardiography) left ventricular function parameters between the beginning and the 1st, 3rd, and 6th months of therapy. The results of this study suggest that IFN-alpha therapy does not cause a significant deterioration in cardiac function in patients with chronic hepatitis B infection, and it may be used safely in patients without cardiac disease.