Electrocardiographic features of failed and recurrent right ventricular outflow tract catheter ablation of idiopathic ventricular arrhythmias

Introduction: Various ECG algorithms have been proposed to identify the origin of idiopathic outflow tract (OT)-ventricular arrhythmia (VA). However, electrocardiographic features of failed and recurrent right ventricular outflow tract (RVOT) ablation of idiopathic OT-VAs have not been clearly elucidated. Methods and results: A total of 264 consecutive patients (mean age: 44.0 +/- 13.0 years, 96 male) undergoing RVOT ablation for OT-VAs with a transition >= V-3, including 241 patients (91.6%) with initially successful procedures and 23 patients (8.4%) with failed ablation. Detailed clinical characteristics and ECG features were analyzed and compared between the two groups. VAs with failed RVOT ablation had larger peak deflection index (PDI), longer V-2 R wave duration (V(2)Rd), smaller V-2 S wave amplitude, higher R/S ratio in V-2, higher V-3 R wave amplitude, and larger V-2 transition ratio than those with successful ablation. Multivariate analysis demonstrated that PDI, V(2)Rd, V-2 transition ratio, and pacemapping score acquired during mapping independently predicted failed ablation (P = 0.01, P = 0.01, P = 0.01, and P< 0.001, respectively). In 31 recurrent cases (12.8%) after initially successful ablation, multivariate Cox regression analysis showed that only the earliest activation time acquired during mapping predicted the recurrences after successful ablation (P = 0.001). The recurrent cases displayed different ECG features comparing with those with failed ablation. Conclusion: The electrocardiographic features of failed RVOT ablation of idiopathic OT-VAs with a transition >= V-3 were characterized by PDI, V(2)Rd, V-2 transition ratio, and pacemapping score acquired during mapping, unlike the recurrent RVOT ablation.