Successful Epicardial Ablation of Ventricular Arrhythmia From the Epicardial Side of the Interventricular Septum.

BACKGROUND

We describe a successful ablation of ventricular arrhythmia (VA) originating from the epicardial anterior interventricular groove.

CASE SUMMARY

A 16-year-old boy with high-burden VA was referred to an electrophysiology laboratory. Endocardial pace mapping pointed to near right ventricular apex with 92% surface QRS correlation, but ablation resulted in right bundle branch block and maintenance of VA. Epicardial mapping revealed VA origin in the midsection of the anterior interventricular groove. Successful radiofrequency ablation was achieved while a guidewire was maintained inside the left anterior descending artery as a precautionary measure. The patient remained arrhythmia-free and without left anterior descending artery injury after the procedure.

DISCUSSION

Epicardial idiopathic VAs usually arise from the crux of the heart or left ventricle summit; thus, an interventricular groove origin is unusual. Epicardial fat in the region may play a role in arrhythmogenesis.

TAKE-HOME MESSAGE: VA with a QS pattern in leads I and V to V may prompt epicardial mapping, particularly when insufficient pace mapping or the absence of an earliest local signal is found during endocardial mapping.