Ab-452673-3 outcomes of functional substrate mapping of ventricular tachycardia (func-vt) - an international matched prospective registry

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. This multicentre prospective propensity-matched registry of functional VT substrate mapping (Func-VT registry) aims to compare procedural and follow-up outcomes with conventional mapping and ablation. Procedure times, mortality, and probability of ATP/ICD shocks were compared to the matched institutional cohort. We conducted an international prospective registry of 44 patients with ischemic heart disease undergoing functional mapping of VT through single extra stimuli to invoke decremental signal delay (Sense Protocol). Areas of functional signal delay were targeted for ablation in conjunction with conventional pacemapping or entrainment mapping where appropriate. This data was compared against a matched institutional cohort of patients undergoing conventional substrate guided ablation through entrainment, pacemapping or substrate only guided ablation. The patients were propensity-matched to age, gender and left ventricular ejection fraction. There were 44 patients (mean age of 70 ±10.64 years, 95% males, mean ejection fraction (EF) of 33%) in the Func-VT registry matched to 49 patients in the institutional cohort (mean age of 72 ±9.42years, 90% males, mean EF of 29%). The median procedure time was 178min in the registry patients compared with 185min in the institutional cohort (p=<0.005). Post ablation, there was a mean ATP reduction of 13.74 ±4.53 (p=0.002) and a mean shock reduction of 4.078 ±5.74 (p=0.01) in the Func-VT registry as compared to the institutional cohort. The 12-month all-cause mortality rate was 4.5% in the registry vs 20.4% in the institutional data (OR 1.46, p=0.04). This prospective study shows that targeting functional signals using the Sense protocol in addition to conventional mapping methods improved outcomes in terms of device therapy and reduced procedure time in VT ablation when compared to previous institutional methods.