Randomized Comparison of Bipolar vs Unipolar Plus Bipolar Recordings During Atrioventricular Junction Ablation : Importance and Efficacy of Unipolar Recording

Background No prior studies have clarified the utility and efficacy of unipolar recording for identifying successful sites for atrioventricular junction (AVJ) ablation. Methods and Results Thirty-six patients underwent radiofrequency (RF) AVJ ablation for drug-resistant atrial fibrillation (AF) or AF/flutter. AVJ ablation was performed with either bipolar (Bi-group; n=18) or unipolar plus bipolar recording (Uni-group; n=18). In the Uni-group, the primary parameter used to select ablation sites was a QS or rS morphology of the His bundle unipolar recording. There was no significant difference between the 2 groups for the bipolar electrogram characteristics at the successful ablation site. However, in the Uni-group, the procedure time and fluoroscopy duration were shorter (both p<0.05), and the total number of RF energy applications less (p<0.05) than in the Bi-group. In the Uni-group, unipolar His bundle recordings could be assessed in 26 (76%) of 34 RF energy applications: Complete atrioventricular block was obtained at 15 (83%) of 18 sites with QS morphology and in 3 (37%) of 8 sites with rS morphology on the unipolar His bundle recording. Conclusions AVJ ablation can be achieved more efficiently and with fewer RF energy applications when guided by unipolar recordings than by bipolar recordings alone.