Endocardial Scar-Homogenization With vs Without Epicardial Ablation in VT Patients With Ischemic Cardiomyopathy.

Abstract

In this study, the authors investigated the ablation success of scar homogenization with combined (epicardial+ endocardial) vs endocardial-only approach for ventricular tachycardia (VT) in patients with ischemic cardiomyopathy (ICM) at 5 years of follow-up. Best ablation approach to achieve long-term success rate in VT patients with ICM is not known yet. Consecutive ICM patients undergoing VT ablation at our center were classified into group 1: endocardial+ epicardial scar homogenization and group 2: endocardial scar homogenization. Patients with previousopen heart surgery were excluded. Epicardial ablation was performed despite being noninducible after endocardial ablation in all group 1 patients. All patients underwent bipolar substrate mapping with standard scar settings defined as normal tissue >1.5mV and severe scar<0.5mV. Noninducibility of monomorphic VT was the procedural endpoint in both groups. Patients were followed up every 4months for 5 years with implantable device interrogations. A total of 361 patients (group 1: n=70 and group 2: n=291) were included in the study. At 5 years, 81.4% (n=57/70) patients from group 1 and 66.3% (n=193/291) from group 2 were arrhythmia-free (P = 0.01) Of those patients, 26 of 57 (45.6%) and 172 of 193 (89.1%) from group 1 and group 2 respectively were on anti-arrhythmic drugs (AAD) (log-rank P < 0.001). After adjusting for age, sex, and obstructive sleep apnea, endo-epicardial scar homogenization was associated with a significant reduction in arrhythmia-recurrence (HR: 0.48; 95%CI: 0.27-0.86; P = 0.02). In this series of patients with ICM and VT, epicardial substrate was detected in all group 1 patients despite being noninducible after endocardial ablation. Moreover, combined endo-epicardial scar homogenization wasassociated with a significantly higher success rate at 5 years of follow-up and a substantially lower need for antiarrhythmic drugs after the procedure compared with the endocardial ablation alone.