Abstract 2871: Clinical Study to Investigate the Accuracy of the “Post-Pacing Interval” Method to Detect the Optimal Site for Catheter Ablation in Patients with WPW Syndrome as a Typical Model of Macro-reentry
Background: The “post-pacing interval” (PPI) method has been used to investigate whether an endocardial site of interest is a requisite part of the reentrant circuit and is the optimal site for catheter ablation.
Methods: A total of 15 patients (average age; 37±4 yrs) with accessory pathway (AP) and atrioventricular reciprocating tachycardia (AVRT) were included in this study. Multi-polar electrode catheters were introduced and positioned at the area of interest, and detailed electrophysiological study was performed to determine AP location. AP location was verified by successful complete elimination of conduction over the AP by catheter ablation. Constant pacing from the atrial site of the atrioventricular annulus (from the coronary sinus for left-sided APs and along the atrial site of the tricuspid annulus for right-sided APs) was performed during sustained stable AVRT at a cycle length 20 msec shorter than that of the tachycardia cycle length. The exact site of the AP was defined as the “definite site.” PPI was measured at the “definite site” location and at sites 5 mm and 10 mm away from this location to assess accuracy of the PPI method in terms of differentiating between sites just on the AP and those outside it.
Results: In all cases, PPIs measured at “definite sites” were 24±3 msec, whereas PPIs measured at sites 5 mm and 10 mm away from the AP definite sites were between 37±7 and 43±6 msec, respectively, in all instances. There was a significant difference between PPI values recorded at the definite site and those recorded outside of definite sites (p<0.05).
Conclusions: PPI within 25 msec is a very reliable indicator to guide the ablation catheter with almost pin-point accuracy to a location just on the definite site of the AP. Any site where the PPI is >30 msec is located outside the definite site of the AP.