Polymorphic Ventricular Tachycardia and Torsades in Methadone Therapy Captured by Loop Recorder

Methadone is associated with QT prolongation and risk of torsades de pointes, particularly at higher doses, and management becomes challenging when the precipitating factor cannot be eliminated.

A 56-year-old man on high-dose methadone with an implantable loop recorder experienced 3 episodes of polymorphic ventricular tachycardia and ventricular fibrillation, including a prolonged 94-second syncopal event. Device electrograms demonstrated pause-dependent initiation with short-long-short sequences and marked QT prolongation preceding arrhythmia onset. Despite limited follow-up, he ultimately agreed to wearable cardioverter-defibrillator therapy and subsequent implantable cardioverter-defibrillator (ICD) placement for secondary prevention.

This case highlights methadone-associated malignant ventricular arrhythmias, the importance of continuous rhythm monitoring, and the role of ICD insertion when the offending agent cannot be safely withdrawn.

In high-risk patients with recurrent ventricular arrhythmias on methadone, individualized monitoring and ICD therapy may be warranted.