Newer Antiarrhythmic Agents for Atrial Fibrillation: Shall we Eventually do away with Proarrhythmia?

Abstract

Despite advances in drug therapy for the treatment of atrial fibrillation (AF), there continues to be a need for antiarrhythmic agents that have improved safety and efficacy profile. Unfortunately, drugs that block the potassium channels or are multichannel blockers, although they may be effective antiarrhythmics, they delay repolarization and thus they confer a proarrhythmic effect by inducing torsade de pointes, a potentially lethal ventricular arrhythmia. Most newer antiarrhythmic drugs are potassium channel blockers and this limits their usefulness. A less toxic agent compared to amiodarone, the noniodinated analogue of amiodarone (dronedarone) is being investigated; however, it appears already unsafe in patients with heart failure. Future antiarrhythmic agents will probably be atrial-selective blocking agents without affecting repolarization in the ventricular myocardium and thus avoid ventricular proarrhythmia with its attendant life-threatening consequences.