Non-invasive evaluation of the haemodynamic effects of amiodarone.

Sixteen patients were examined hemodynamically with echocardiography, calibrated apexcardiography, and systolic time intervals before treatment, after 1 week treatment with amiodarone 600 mg daily and after 2-4 months treatment with 300 mg daily. During the treatment thyroid function was controlled. The echocardiogram showed a small increase in shortening fraction, while left ventricular dimensions did not change significantly. The apexcardiogram revealed minor changes, which could not be interpreted as being due to changes in contractility. The systolic time intervals showed marked decreases in preejection period index and preejection period/left ventricular ejection time. These changes could not be correlated to changes in serum thyroxine, which was the only thyroid parameter to change significantly. The hemodynamic changes during amiodarone treatment were interpreted as mainly being due to a decrease in afterload while possible changes in preload and myocardial contractility were of minor importance.