Abstract 15404: Changes in Atrial Fibrillation Cycle Length in the Pulmonary Vein by Endocardial High-Frequency Stimulation Before and After Ganglionated Plexus Ablation
Introduction: Experimental and clinical studies suggest that ganglionated plexus (GP) activation plays a significant role in the initiation and maintenance of atrial fibrillation (AF). In animal subjects, high frequency stimulation (HFS) of the GP produces repetitive short bursts of rapid, irregular firing in the adjacent pulmonary vein, initiating sustained AF. We assessed the hypothesis that the pulmonary vein firing produced by HFS changes before and after GP ablation.
Methods: Twenty-four patients undergoing catheter ablation for AF (12 with paroxysmal AF, 12 with persistent AF) were enrolled. The GP was identified and localized, using endocardial high- frequency stimulation (20Hz, 20V, 10ms pulse width). Sites showing a vagal response, which is defined as ≥50% increase in mean R-R interval during AF, were assigned as GP sites. AF cycle length was obtained from the adjacent pulmonary vein, distant pulmonary vein, coronary sinus, and high right atrium catheter recordings. Twenty cycles were counted before and after each HFS episode. After radiofrequency application to the GP site, the HFS was repeated at the same site, and cycle length were counted before and after HFS episode.
Results: A total of 55 HFS episodes with vagal responses were analyzed. The greatest reductions in AF cycle length were seen in the adjacent pulmonary vein (17% reduction, 166±51 to 138±32ms, p=0.005),distant pulmonary vein (5.8% reduction, 152±35 to 143±32ms, p=0.03) ,coronary sinus(0.2% increase,157±27 to 158±26ms, p=N.S), and right atrium(3.5% reduction,176±42 to 170±33ms, p=N.S). At the 39 sites where vagal responses disappeared after radiofrequency application, significant reduction of the AF cycle length by HFS in the adjacent pulmonary vein was not seen (1.8% reduction, 171±51 to 168±32ms, p=N.S). However, at the 16 sites where vagal response was still present, a significant reduction in AF cycle length by HFS was observed in the adjacent pulmonary vein (18% reduction, 172±29 to 141±18ms, p<0.001).
Conclusion: HFS of the GP has a strong influence on adjacent pulmonary vein firing. This result suggests that GP may be a potential ablation target for AF.
- © 2012 by American Heart Association, Inc.