Used primarily as an antiarrhythmic agent in the treatment of cardiac rhythm disorders, including both ventricular and supraventricular arrhythmias such as atrial fibrillation and atrial flutter. The (S)-enantiomer of propafenone is more potent in blocking sodium channels in cardiac tissue compared to the (R)-enantiomer, allowing effective treatment at lower doses while stabilizing abnormal electrical activity in the heart. It also exhibits some beta-blocking activity, though less pronounced than in the (R)-enantiomer, contributing to its overall effectiveness in managing arrhythmias. Employed in both acute and chronic settings to maintain normal sinus rhythm in patients with documented arrhythmias. Often prescribed when other antiarrhythmic drugs are ineffective or not tolerated. Requires careful monitoring due to potential proarrhythmic effects and variable metabolism among patients.