Abstract 17741: Bipolar Radiofrequency Catheter Ablation for Refractory Ventricular Outflow Tract Arrhythmias
Objectives: Premature ventricular contractions (PVCs) originating from the ventricular outflow tract region are often successfully ablated using standard unipolar radiofrequency ablation (RFA). However, on occasion, unipolar RFA may fail. Here we report three cases in which bipolar RFA was successful in abolishing outflow tract PVCs when unipolar RFA was ineffective.
Methods: Activation mapping of the right and left ventricular outflow tract (RVOT & LVOT), coronary sinus, and aortic root was performed during PVCs using an electronantomic mapping system (CARTO). Bipolar RFA was performed using an externally-irrigated catheter (ThermoCool Navistar and Celsius) at sites of earliest activation on opposing sides of the interventricular septum after unipolar RFA at these sites failed to abolish PVCs. For bipolar RFA, the RF generator configuration was modified using a custom-built cable allowing one catheter to be designated the active and a second catheter the return electrode.
Results: The mean age of the three patients (2 male, 1 female) was 56 years (range 29-81 years) and the mean LVEF was 45% (range 30-60%). In all patients, earliest activation in the RVOT was posteroseptal. Earliest activation on the left side was in the right coronary cusp (RCC) in 2 patients and left coronary cusp (LCC) in 1 patient. Unipolar RFA delivered sequentially at the earliest RVOT and left sided sites failed to eradicate the PVCs in all 3 patients. Subsequently, bipolar RFA was applied between ablation catheters placed at the earliest RVOT and LVOT sites, which successfully eradicated the PVCs in all cases (example in figure). There were no recurrences after a mean of 61 days follow-up (range 38-88 days).
Conclusions: This report demonstrates the potential utility of bipolar RFA in patients with outflow tract PVCs that fail unipolar RFA.
- © 2012 by American Heart Association, Inc.