Catheter Ablation of Peri-Conduit Ventricular Tachycardia in a Patient with Rastelli Procedure for Double Outlet Right Ventricle with Malposition of Great Arteries.

Occurrence of ventricular tachycardia (VT) remains a risk in repaired congenital heart disease (CHD).1)2)3) We report a case of successful catheter ablation of drug-refractory peri-conduit VT in a patient with Rastelli-type repair using a right ventricle-to-pulmonary artery (RV-PA) conduit. Electroanatomic activation and voltage maps of the RV were created and merged with cardiac CT using the CARTO system v4.3 (Biosense Webster, Diamond Bar, CA, USA) and an open-irrigated tip Thermocool™ catheter (Biosense Webster) (Fig. 1). During electrophysiological study, programmed stimulation induced 2 VTs, including a left bundle branch block morphology with superior and inferior axes (clinical VT, Fig, 2A and Fig. 2B, respectively). Entrainment and/or activation mapping identified the 2 VT circuits sharing a common conduction isthmus localized between the tricuspid annulus (surgical scar) and the RV-PA conduit (Fig. 2). The exit of VT1 was located between the superior tricuspid annulus and RV-PA conduit (Fig. 3A, Supplementary Video 1 in the online-only Data Supplement), while VT2 exited at the anterior RV scar border (Fig. 3B). Radiofrequency energy delivered in a temperature-controlled mode at 35-40 Watts targeting an impedance drop of 10 Ohms at the isthmus, where an isolated late potential was recorded, could not induce VT (Fig. 3C).

Fig. 1

Fig. 2

Fig. 3

Anatomical boundaries and surgical scars contribute to the important substrates for VT arrhythmogenesis in repaired CHD and can be eliminated by ablation. Pre-procedural evaluation of surgical anatomy and image reconstruction provides pivotal information for identifying potential substrates and selecting ablation strategies.4)5)