Anatomic-guided ablation of the right ganglionated plexi validated by the automatic fractionation map

Abstract

Abstract Background and aim Cardiac autonomic modulation through endocardial ablation of atrial ganglionated plexi (GP) is an alternative strategy in selected patients with severe vagal induced bradyarrhythmias. A strictly anatomical approach targeting the right GPs has demonstrated good success rates but is an empirical approach and has yet to be validated. The presence of fractionated electrograms has been associated with the areas of GPs and can be automatically mapped (fractionation map). The aim of this study was to compare the empirical ablated area, to the automatically assessed area of GPs based on the presence of fractionated electrograms (FEs). Methods We studied eight consecutive patients referred for parasympathetic modulation. A high-density map of the left and right atria (LA, RA) in sinus rhythm was performed. The settings for the automatic map were as follows: bipolar high pass filter of 500 Hz, a fractionation threshold of 4, and a width of 5 ms. The ablation was empirically performed by an operator blinded to the results of the fractionation map, as per site protocol. The ablation was aimed at the anatomic locations of the right GPs in the LA and RA. At the anterior and inferior aspect of the right superior pulmonary vein and inferior aspect of the right inferior pulmonary vein on the LA, and posterior RA opposite to the LA RF applications and around the coronary sinus ostium on the RA (Figure). Before ablation, 2 mg of atropine was administered in bolus, and the increase in heart rate was registered and repeated at the end of the procedure. After the operator completed the ablation, access to the fractionation map was available, and additional radiofrequency (RF) applications were applied as needed (Figure). The number of additional RF applications to cover all the areas with FEs was assessed. Success was defined as an absence of response to atropine after the procedure. Results Three patients underwent autonomic system modulation only, and five underwent additional pulmonary vein isolation (PVI). The mean age was 66 (50-77) years, five males. The median mapping time of the LA and RA was 11 (17-7) and 14 (9-18) min. All patients underwent successful parasympathetic modulation. The initial median (Q1-Q3) increase in heart rate with atropine was 34 (23-39)% versus 0 (0-2)% after ablation, p=0.012. The differences between empiric and FEs map-guided ablation are depicted in the Table. The additional number of points was low. However, a median of 9 (5-15) additional points were added. Conclusions A purely anatomic-guided procedure directed only at the atrial right GPs is usually enough as a therapeutic approach for cardiac autonomic modulation, however, the fractionation map tool helped validate the method and ensure success at the first pass.