What is the primary mechanism of action of amiodarone?

The primary mechanism of action of amiodarone is that it prolongs repolarization. This effect is particularly significant because it enhances the duration of the action potential in cardiac myocytes, which helps to stabilize cardiac rhythms. By prolonging repolarization, amiodarone effectively prolongs the QT interval on an electrocardiogram, reducing the risk of tachyarrhythmias and allowing longer recovery times for the heart tissue between beats. This characteristic is vital in treating various types of arrhythmias, particularly atrial fibrillation and ventricular tachycardia, as it helps prevent the re-entry pathways that can lead to these conditions.

Amiodarone's ability to prolong repolarization makes it an effective antiarrhythmic agent, as it stabilizes the myocardial electrical activity and can help convert arrhythmias back to a normal rhythm. Its wide array of effects on different ion channels, including sodium, potassium, and calcium channels, contribute to its multifunctional role in cardiac rhythm management.