Radiofrequency catheter ablation of idiopathic left ventricular tachycardia originating in both left posterior and anterior fascicles.

A 45-year-old woman underwent radiofrequency ablation (RFA) for symptomatic idiopathic left ventricular tachycardia (ILVT). The clinical arrhythmias had two different patterns, a wide QRS tachycardia with right bundle branch block (RBBB) and left axis deviation (LAD) and another with RBBB and right axis deviation (RAD). The electrophysiology study localized the origin of tachycardias to the midinferior and superior ventricular septum, respectively. RFA terminated successfully ILVT with RBBB and LAD morphology, but another pattern could not be ablated. Noncontact mapping revealed the earliest site of activation at the superior septum. RFA at this site terminated successfully ILVT with RBBB and RAD.