Outcomes of functional substrate mapping of ventricular tachycardia (Func-VT) - an international propensity-matched prospective registry

Abstract Funding Acknowledgements Type of funding sources: None. Background Dynamic substrate changes play a key role in facilitating conduction delay and re-entry in ventricular tachycardia (VT) circuits. Extrastimuli pacing can unmask functional channels demonstrated by dynamic delay, which may play a role in the VT circuit. We have previously developed sense protocol mapping, using short coupled single extrastimuli to delineate areas of maladaptive conduction delay, which play an essential part in VT development. Purpose We conducted a multicentre prospective propensity-matched registry of functional VT substrate mapping (Func-VT registry) compared with conventional mapping. Procedure times, mortality, and probability of ATP/ICD shocks were compared to the matched institutional cohort. Methods Data prospectively analysed from an international registry of patients undergoing ablation for Ventricular tachycardia. Data was gathered from multiple sites evaluating outcomes of VT ablation using sense protocol mapping and comparing the results with institutional cohort using conventional methods of entrainment, activation mapping, late potential and pace mapping. The date was propensity-matched to age and left ventricular ejection fraction. Results There were 41 patients (mean age of 60 years, 80% males, mean ejection fraction: 35%) in the func-VT registry. The median procedure time was 161 minutes compared with 305 in the institutional cohort (p=<0.001). 85% of patients were free from symptomatic VT/ anti-tachycardia pacing or ICD shocks at a median follow-up of 340 days. Mean shocks per-patient burden decreased from 3.5 to 0.08 in the same period (p=0.03). Figure 1 shows survival curves demonstrating the probability of death in the Funct-VT registry patients vs institutional cohort (p=0.011). Conclusions VT functional mapping registry provides real-world data regarding acute and long-term outcomes and complications. It shows better outcomes and improved survival in patients who underwent ablation using sense protocol mapping.