B-PO05-196 PREDICTIVE INDICES OF VENTRICULAR STIMULATION PROTOCOLS IN TETRALOGY OF FALLOT PATIENTS WITH ICDS AND SUBSEQUENT THERAPIES

Abstract

Patients with repaired Tetralogy of Fallot (ToF) are at increased risk for ventricular arrhythmias (VA). Utility of a peri-surgical pulmonary valve replacement (PVR) ventricular stimulation protocol to assist with risk stratification for sudden cardiac death has been well established in this population. However, current protocol-guided ICD implantation may lack specificity. We sought to evaluate post-surgical PVR electrophysiology study (EPS) indices in protocol-guided ICD patients to define potential predictive markers of subsequent, appropriate ICD therapies. All ToF patients with protocol-guided ICD implants (N=14) at two centers were included for retrospective analysis. Patients with appropriate ICD therapies were compared to those without or with only inappropriate therapy using chi-square tests and unpaired t-tests. Six patients received appropriate ICD therapies and eight received no therapy. Inducibility with double extrastimuli, during post-PVR EPS, was predictive of appropriate therapy (P=0.024) while inducibility only with extrastimuli <200 ms was predictive of no therapy (P=0.01). Isoproterenol use (P=0.19) and site of pacing that led to induction (P=0.277) did not correlate with subsequent ICD therapies. Inappropriate shocks were not significantly different between groups (P=0.1). Aggressive pacing protocols, including triple and extrastimuli <200 ms, are more likely to induce VAs without subsequent appropriate clinical therapies in patients with repaired Tetralogy of Fallot.