Bipolar Radiofrequency Catheter Ablation for Refractory Ventricular Outflow Tract Arrhythmias

INTRODUCTION: Standard unipolar radiofrequency ablation (RFA) is typically successful in eliminating premature ventricular contractions (PVCs) originating from the ventricular outflow tract region. In a minority of cases, this approach may be ineffective. We report 4 cases where bipolar RFA was attempted after failed unipolar RFA. METHODS: From a total of 73 consecutive PVC ablations, 4 patients underwent bipolar RFA after failed unipolar ablation. Three-dimensional electroanatomic activation mapping of the right and left ventricular outflow (RVOT and LVOT), coronary sinus, and aortic root was performed. RESULTS: Mean age was 53 ± 22 years, 3 male. The mean 24-hour PVC burden in these patients was 33,107 ± 8,712. In 3 of 4 patients, the RVOT activation was earlier than the left side. The earliest activation on the left was in the right coronary cusp in 2 patients and left coronary cusp in 2. Unipolar RFA delivered sequentially at the site of earliest RVOT and then earliest aortic cusp sites failed to eradicate the PVCs in all 4 patients. Subsequently, bipolar RFA was applied between irrigated catheters placed at the earliest RVOT and aortic root sites. This approach eliminated PVCs in 3 of 4 (75%) cases. At a median follow-up of 4 months, those with successful bipolar RFA had no recurrence of clinical PVCs. CONCLUSIONS: This report demonstrates the potential utility of bipolar RFA in patients with outflow tract PVCs that fail unipolar RFA.