Azimilide is primarily used in the treatment of cardiac arrhythmias, particularly atrial fibrillation and ventricular arrhythmias. It functions as a class III antiarrhythmic agent, helping to stabilize the heart's electrical activity by blocking potassium channels. This action prolongs the cardiac action potential and refractory period, reducing the likelihood of abnormal heart rhythms. Azimilide is often considered for patients who have not responded well to other antiarrhythmic medications, offering an alternative to manage and control irregular heartbeats effectively. Its use is closely monitored due to potential side effects, including the risk of proarrhythmia, which can exacerbate existing heart rhythm issues.