Marked QTc Interval Prolongation Associated With Dronedarone in Paroxysmal Atrial Fibrillation and No Structural Disease.

Dronedarone, a multichannel antiarrhythmic drug, was developed as a safer alternative to amiodarone for atrial fibrillation. Although initially considered to have a lower proarrhythmic risk, post-marketing data and clinical experience suggest otherwise. We describe the case of a 44-year-old male with paroxysmal atrial fibrillation and no structural heart disease who developed marked QTc prolongation while receiving dronedarone, despite being asymptomatic. This case highlights the potential for clinically silent but significant QTc prolongation during dronedarone therapy, underscoring the importance of careful ECG monitoring, even in low-risk patients.