B-po04-126 empiric ablation of ventricular fibrillation triggers guided by pacemap matching of stored intracardiac defibrillator electrograms

While ablation of PVC triggers has been shown to be effective to prevent recurrent VF, strategies are less clear when the trigger is infrequent or the morphology of the trigger has not been recorded on 12-lead ECG. Report a novel empiric ablation strategy to target Purkinje and outflow regions based on pacemap matching to stored ICD electrograms of the PVC trigger. Eleven patients with drug-refractory VF/PMVT with ICD shocks without spontaneous PVC triggers were retrospectively analyzed. The procedure protocol incorporated systematic pacemapping from: moderator band, left posterior and anterior fascicles, and outflow tract; with simultaneous comparison between the ICD electrogram morphology and the stored near-field and far-field ICD electrogram template of the clinical PVC trigger. The left Purkinje system matched pacemaps of stored intracardiac EGM of clinical PVC trigger in 63% (n=7), followed by the left outflow tract 18% (n=2), antero-lateral papillary muscle (n=1), LV summit region(n=1) and moderator band (n=1). After a mean follow-up of 7 months, the freedom of VF/PMVT ICD shock was 70%. A 30% of patients experienced recurrence. Post-ablation shock burden was reduced from 4 (IQR 2-6) to 0.7 (IQR 0-1) (p = 0.005). The strategy of interrogating the fascicles and outflow tract regions by pacemap matching with the stored ICD helps to guide empiric ablation and results in significant reduction in VF therapy burden.