B-po05-117 ventricular tachycardia involving the conduction system in structural heart disease: prevalence, mechanisms, and outcomes

While conduction system ventricular tachycardia (VT) in idiopathic substrates has been well characterized. The spectrum of monomorphic VT involving the Purkinje system in structural heart disease (SHD) is incompletely described. Analyze the prevalence, mechanisms, and outcomes of conduction system VTs in structurally abnormal hearts at a single institution. Retrospectively analyzed 340 consecutive scar-related monomorphic VT ablation procedures performed at the University of Chicago from March 2016 to January 2021. Patient characteristics, procedural outcomes, recurrence of VT and clinical course were reviewed. Fourteen patients accounted for 15 procedures (4.4% of total ablations) targeting the conduction system. The mean age was 55±12 years, 23% female, mean ejection fraction 29±13%, 43% ischemic heart disease, and 57% non-ischemic heart disease. In this cohort 64% had previous ablations for VT prior to admission with a mean of 1±0.9 procedures per patient; 93% of the patients were on antiarrhythmic medications prior to the procedure. The spectrum of arrhythmia mechanisms included 60% bundle branch reentry, 13% fascicular reentry, 13% scar VT with fascicular exit, and 13% interfascicular reentry. Two patients expired during their hospitalization. No patient had a new device requirement post ablation. Eighty-six percent of the patients demonstrated freedom from VT post procedure. A diverse spectrum of Purkinje involvement in reentrant VT was observed in patients with structural heart disease. Twelve out of 14 patients were free of VT post ablation.