Verapamil-sensitive fascicular ventricular tachycardia precipitated by promethazine overdose.

Verapamil-sensitive fascicular tachycardia is a type of ventricular tachycardia (VT) involving the specialised cardiac conducting tissue. Drug overdose is an important cause to consider when assessing patients with a new presentation of a broad complex tachycardia. Multiple antihistamines have been implicated as pro-arrhythmic, but these tend to precipitate Torsades de Pointes via drug-induced QT prolongation. We present an educational case of a Verapamil-sensitive fascicular VT with typical electrocardiogram (ECG) characteristics, which developed immediately following an overdose of promethazine and which was terminated successfully with verapamil, in a young person with a structurally normal heart. There have been no previous published reports of promethazine precipitating a fascicular VT and we aim to highlight this unusual link and the benefits of early recognition and management of similar presentations.