Why is neuromodulation effect of pulmonary vein isolation not same in all cases?

Abstract

Abstract Funding Acknowledgements Type of funding sources: None. Background Cardiac ganglionated plexi (GPs) of the autonomic system are primarily located in major epicardial fat pads adjacent to the left atrium and pulmonary vein junctions. These structures may play a central role in both the initiation and maintenance of atrial fibrillation (AF). Previous studies reported modification of GPs during pulmonary vein isolation (PVI) may increase rate of sinus node and AF-free survival. However, a deficiency certainly existed why is modification of GPs observed in some patients during PVI but not in others? Purpose We aimed to evaluate ratio of ablation points within classical antral circumferential ablation lines for PVI and distribution of 4 major atrial ganglionated plexus. Methods Thirty-eight consecutive patients undergoing ablation of GP for vagally mediated bradyarrhythmias were evaluated. All GP sites were detected by using previously defined fragmented electrogram based strategy which is a validated tool when compared with a combination of spectral analysis and high frequency stimulation to detect GPs. Estimated ablation lines for antral circumferential ablation was defined as a circumferential isolation line performed ≥1 cm away from the pulmonary vein ostium as identified by 3D electroanatomical reconstruction (Figure 1). The total number of ablation points in each GP sites and ratio of ablation points within estimated antral circumferential ablation lines were recorded. Results The great majority of ablation points were detected at the insertion of the right pulmonary veins. Number of ablation points in each GP site in descending order is as follows: (1) the right superior GP = 13.6 ± 6; (2) the left superior GP = 10.5 ± 5; (3) the right inferior GP = 5.9 ± 4; and (4) the left inferior GP = 2.5 ± 3. The ratio of ablation points within estimated antral circumferential ablation lines was higher in right-sided GPs (50.5%±24 for the right superior GP and 30.2%±31 for the right inferior GP vs 18.3%±24 for the left superior GP and 11.6%±26 for the left inferior GP. Figure 2 demonstrates total number of ablation points and the ratio of ablation points within estimated antral circumferential ablation lines in each GP site. Conclusions The present study shows that individual variability of distribution of GPs and how antral ablation was done during PVI might be the main contributors of neuromodulation effect. Further randomized, controlled and multicenter studies should be performed to confirm these findings. Abstract Figure 1