A Novel Technique for the Avoiding Catheter Dislodgment Caused by Atrio-Ventricular Dissociation after Elimination of the Accessory Pathway

We hypothesized that the atrio-ventricular (AV) dissociation occurring after elimination of the accessory pathway conduction during right ventricular (RV) pacing made the stability of the ablation catheter worse. We confirmed this hypothesis by using a pacing model. As a simulation model, sequential ventriculo-atrial (VA) pacing was designed and stud ied in 20 pa tients without VA conduction. Prior to the sequential VA pacing, 3 catheters were positioned in the RV, right atrium (RA) and at the tricuspid valve annulus (TVA), respectively. The sequential VA pacing consisted of continuous RV pacing at a cycle length of 600 ms and RA pacing. The RA was paced at an interval of 125 ms following the RV pacing. To induce AV dissociation, RA pacing was abruptly terminated during continuous sequential VA pacing. We observed the motion of the catheter tip on the TVA before and after RA pacing using fluoroscopy in the 30? right anterior oblique (RAO) and 45? left anterior oblique (LAO) views. The catheter tip position in the end-systolic and end-diastolic phases was confirmed in each projection, and the distance of the catheter tip between these 2 phases was measured. The mean value of the catheter tip distance between the 2 phases obtained with sequential VA pacing and fusion beats was 7.5 ± 3.2 and 21.0 ± 8.3 mm in the RAO (P < 0.001) and 8.0 ± 4.5 and 19.0 ± 8.6 mm in the LAO views (P < 0.001), respectively. Further, we proposed a new pacing maneuver to stabilize the ablation catheter position after the elimination of accessory pathway conduction. Using sequential VA pacing, we examined catheter tip movement during RF current delivery in 6 patients with the concealed Wolff-Parkinson-White syndrome. During RF current delivery, catheter dislodgment did not occur in any patients after the accessory pathway was eliminated when no fusion beats occurred. In conclusion, AV dissociation occurring after elimination of the accessory pathway conduction during RV pacing worsened the stability of the ablation catheter. Furthermore, a new pacing maneuver during the RF application provided a useful method for maintaining stable catheter position for catheter ablation of accessory pathways.