Case 6:
A 36 year old man with a history of repaired Tetralogy of Fallot and recurrent VT despite sotalol therapy and prior catheter ablation presented for repeat ablation. PES from the RV apex and RV outflow tract with up to 4 extra stimuli following drive cycle lengths as short as 300 ms with and without isoproterenol (up to 4mcg/min that elicited sinus tachycardia of ~ 130 bpm) failed to induce VT. Single atrial extrastimuli during isoproterenol infusion induced sustained clinical VT (Figure 4). Programmed stimulation was then performed from the basal inferior RV septum and reproducibly induced VT. Activation and entrainment mapping revealed a circuit utilizing the infundibular septum requiring ablation from the RV and aortic root for interruption, as previously reported.13