Elimination of Local Abnormal Ventricular Activities A New End Point for Substrate Modification in Patients With Scar-Related Ventricular Tachycardia

Background —Catheter ablation of ventricular tachycardia (VT) is effective and particularly useful in patients with frequent defibrillator interventions. Various substrate modification techniques have been described for unmappable or hemodynamically intolerable VT. Non-inducibility is the most frequently used endpoint but is associated with significant limitations such that the optimal endpoint remains unclear. We hypothesized that elimination of local abnormal ventricular activities (LAVA) during sinus rhythm or ventricular pacing would be a useful and effective endpoint for substrate-based VT ablation. As an adjunct to this strategy, we used a new high density mapping catheter and frequently employed epicardial mapping. Methods and Results —Seventy patients (67±11 y, 7 female) with VT and structurally abnormal ventricle(s) were prospectively enrolled. Conventional mapping was performed in sinus rhythm in all while a high density Pentaray TM mapping catheter was used in the endocardium (n=35) and epicardially. LAVA were recorded in 67 patients [95.7%, 95% confidence interval (CI; 89.2%, 98.9%)]. Catheter ablation was performed targeting LAVA using an irrigated-tip catheter placed endocardially via a transeptal or retrograde aortic approach or epicardially via the sub-xiphoid approach. LAVA were successfully abolished or dissociated in 47 of 67 patients [70.1%, 95% CI (58.7%, 80.1%)]. In multivariate analysis, LAVA elimination was independently associated with a reduction in recurrent VT or death [hazard ratio 0.49, 95% CI (0.26, 0.95), P=0.035] during long-term follow-up (median 22 months). Conclusions —LAVA can be identified in most patients with scar-related VT. Elimination of LAVA is feasible and safe and associated with superior survival free from recurrent VT.