PO-699-06 ELECTROPHYSIOLOGICAL STUDY PRIOR TO PLANNED PULMONARY VALVE REPLACEMENTIN PATIENTS WITH SURGICALLY REPAIRED TETRALOGY OF FALLOT

Abstract

Ventricular arrhythmias (VAs) are the most common cause of death in patients with repaired Tetralogy of Fallot (rTOF). However risk stratification remains challenging. We examined outcomes following programmed ventricular stimulation (PVS) during electrophysiological studies (EPS), with or without subsequent ablation, in patients with rTOF planned for pulmonary valve replacement (PVR). All consecutive patients aged ≥18 years with rTOF referred to our institute from 2010 to 2018 for PVR were included. Right ventricular (RV) voltage maps were created and PVS performed from two different sites (apex and infundibulum), including with isoproterenol if the patient was not inducible at baseline. Catheter or surgical cryoablation was performed when patients were inducible or when anatomical isthmuses (AIs) were judged to have the potential to sustain reentrant VAs. Post-operative EPS was undertaken to guide decisions regarding implantable cardioverter-defibrillator (ICD) implantation if patients required surgical cryoablation to complete linear lesions or in cases of persistent inducibility after catheter ablation. 77 patients (36,2 +/- 14,3 years old, 71% male) were included. 18 were inducible and 22 % needed isoproterenol infusion for inducibility. Ablation was performed in 28 patients (17 inducible, 11 non-inducible with slow conduction isthmuses). 5 patients were inducible after catheter ablation, they benefited from surgical cryoablation at the time of PVR and a repeated EPS 3 months post surgery. No patients were inducible at the repeated EPS. ICDs were implanted in five patients: four inducible and one non inducible. During a follow-up of 51 +/- 35 months, 3 patients in the inducible group experienced sustained VAs (two treated by ICD shock) versus none in the non-inducible group (p<0,001). Performing systematic EPS prior to PVR can help stratifying the arrhythmic risk in the repaired TOF population. Identification of pathological isthmuses involved in reentrant VT allows targeted ablation. In our report preemptive ablation in non inducible patients with slow conducting AI seem to be safe. Finally, our protocol can guide ICD implantation.View Large Image Figure ViewerDownload Hi-res image Download (PPT)