Endocardial and endo-epicardial substrate mapping and ablation of ventricular arrhythmia in patients with arrhythmogenic right ventricular cardiomyopathy

Purpose : to compare epicardial and endocardial surface area of local abnormal ventricular activity (LAVA) and low voltage zone (LVZ) and effectiveness of endocardial versus combined endo-epicardial ablation of ventricular arrhythmias in ARVC patients. Methods : a prospective observational “case-control” study comprised 20 patients with ARVC and ventricular arrhythmias referred to catheter ablation. The study group with epicardial approach (EPI group) comprised 10 patients with sustained VT, who signed informed consent for the epicardial access. The control group (ENDO group) comprised 10 patients with sustained VT or frequent symptomatic premature ventricular contractions (PVC). Electroanatomical voltage mapping and LAVA ablation was performed. Results : the patient mean age was 41.4±13.8 years, 70% males; 90% patients in the EPI group had sustained VT, 50% - in the ENDO group. In the EPI group the endocardial unipolar low voltage zone area (LVZ) significantly prevailed over the bipolar endocardial LVZ area: 75.4 cm 2 [IQR: 23.2; 211.9] vs 6.7 cm 2 [IQR: 4.4; 35.5] (Р=0.009). In the ENDO group the LVZ area on unipolar map had a trend toward the prevalence over the bipolar area, but was not statistically different: 12.7 cm 2 (IQR: 0; 46.3) vs 3.65 cm 2 (IQR: 0; 46.3) (Р>0.05). The epicardial bipolar LVZ area prevailed over unipolar epicardial LVZ area: 65.3 cm 2 [IQR: 55.6; 91.3] vs 6.7 cm 2 [IQR: 4.4; 35.3] (Р=0.005). Non-inducibility of any ventricular arrhythmia was achieved in 90% of EPI patients and in 80% of ENDO cases. The median follow-up period was 22.3±10.5 months. During a mean follow-up period freedom of ventricular arrhythmia recurrence was 70% in the EPI group and 100% in the control group (Р>0.05). Conclusion : Although there was a significant difference in bipolar LVZ areas between endo- and epicardial maps, our series showed that endocardial only ablation is an effective strategy in ventricular arrhythmia management in ARVC patients.