Divergent effects of chronic amiodarone administration on systolic and diastolic function in patients with heart disease.

The purpose of this study was to determine the effects of chronic amiodarone treatment on systolic and diastolic function in patients with cardiac disease undergoing treatment for resistant ventricular arrhythmias. Previous studies have shown that chronic amiodarone treatment either has no effect or increases left ventricular ejection fraction, but the effects on diastolic properties of the ventricle have not been defined. Twelve male patients were given loading doses of amiodarone followed by a maintenance regimen. Serial measurements of heart rate, blood pressure, and indexes of systolic and diastolic function were measured by Doppler echocardiographic techniques at baseline conditions and at 2, 8, and 12 weeks of drug therapy. Changes in altered thyroid state were excluded by serial determinations of thyroid function. Amiodarone increased left ventricular ejection fraction (+16%, p < 0.01 by 8 weeks), decreased presystolic ejection period/left ventricular ejection time (-12%, p < 0.01 by 8 weeks), and increased velocity of circumferential fiber shortening (+22%, p < 0.05 by 8 weeks). Amiodarone decreased mitral inflow velocity peak E/peak A (-7%, p < 0.01 by 12 weeks), and increased deceleration and isovolumic relaxation times incrementally (+36% [p < 0.001] and +23% [p < 0.001], respectively, at 12 weeks). Chronically administered amiodarone can improve systolic function and exert a negative lusitropic action in patients with heart disease.