Utility of mapping signals to improve precision of atrioventricular node ablation.

Background: Atrioventricular node (AVN) ablation is effective for rate control in atrial fibrillation. This may require multiple radiofrequency applications to achieve complete atrioventricular block (CAB). In this retrospective study, we tested the hypothesis that mapping the AVN utilizing electrograms (EGMs) on both proximal and distal bipoles of the mapping catheter may improve the likelihood of CAB.
Methods: Lesion characteristics and EGM components on the proximal and distal bipoles of the ablation catheter in first-time AVN ablation procedures were analyzed. Outcomes of each lesion, including presence of CAB, acute recurrence of AVN conduction, new-onset right bundle branch block (RBBB), and junctional escape rhythm, were analyzed. Multivariate binary logistic regression analysis was performed to identify EGM characteristics that independently predicted the outcomes of interest. Lesions with these EGM characteristics were then identified and their outcomes compared with the whole cohort.
Results: A total of 441 ablation lesions were analyzed. EGM characteristics that independently predicted outcomes were the presence of His and atrial EGMs on the distal bipole and the absence of ventricular EGM on the proximal bipole. Among the 25 lesions with all these characteristics, 18 (72%) resulted in CAB compared to the overall cohort rate of 38% (P = 0.001). There was no new-onset RBBB. The likelihood of acute recurrent AVN conduction and junctional escape rhythm were similar.
Conclusion: Combining proximal and distal bipole EGM characteristics of the ablation catheter can improve the accuracy of AVN localization during AVN ablation and avoid right bundle branch injury.
(©2013 Saint Bartholomew's Hospital Pacing and Clinical Electrophysiology ©2013 Wiley Periodicals, Inc.)