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Divergent effects of chronic amiodarone administration on systolic and diastolic function in patients with heart
Insights
Chronic amiodarone treatment improved systolic function, increasing left ventricular ejection fraction. However, it negatively impacted diastolic function, indicated by reduced mitral inflow velocity and prolonged relaxation times in heart disease patients.
Area of Science:
- Cardiology
- Pharmacology
- Echocardiography
Background:
- Amiodarone is used for resistant ventricular arrhythmias.
- Previous research indicates amiodarone may improve or not affect left ventricular ejection fraction.
- The impact of amiodarone on diastolic function remains undefined.
Purpose of the Study:
- To investigate the effects of chronic amiodarone on systolic and diastolic function in cardiac patients.
- To define amiodarone's impact on diastolic properties of the ventricle.
Main Methods:
- Twelve male patients with cardiac disease received amiodarone loading and maintenance doses.
- Doppler echocardiography assessed systolic and diastolic function indexes at baseline and 2, 8, 12 weeks.
- Thyroid function was monitored to exclude confounding effects.
Main Results:
- Amiodarone increased left ventricular ejection fraction (+16%) and velocity of circumferential fiber shortening (+22%).
- Presystolic ejection period/left ventricular ejection time decreased (-12%).
- Mitral inflow velocity peak E/peak A decreased (-7%), while deceleration and isovolumic relaxation times increased (+36%, +23%).
Conclusions:
- Chronic amiodarone administration can enhance systolic function in heart disease patients.
- Amiodarone exerts a negative lusitropic effect, impairing diastolic function.
- Findings highlight amiodarone's dual impact on cardiac mechanics.
Abstract:
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.