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