Incidence and clinical significance of junctional rhythm remaining after termination of radiofrequency current delivery in patients with atrioventricular nodal reentrant tachycardia

The aim of this study was to elucidate the electrophysiologic characteristi cs and clinical significance of the accelerated junctional rhythm (JR) that remains after termination of radiofrequency (RF) current delivery during c atheter ablation (CA) for atrioventricular nodal reentrant tachycardia (AVN RT). Fifty consecutive patients with AVNRT (21M, 29F, age 48 years) underwe nt RF-CA targeting the slow pathway. JR occurred at 124 out of a total of 2 36 ablation sites (53%) during the RF delivery. With 15 RF deliveries (6.4% , n = 10), JR remained after termination of the RF delivery (Post-JR). The mean cycle length of the Post-JR immediately after termination of the RF de livery was 639 +/- 124 ms and its duration was widely distributed from 3 s to more than 1 h. The Post-JR exhibited a spontaneous rate deceleration and overdrive suppression by rapid atrial pacing. The JR during the RF deliver y followed by Post-JR had a greater time span in which the JR appeared, com pared with that without Post-JR. The Post-JR had less sensitivity(18 vs 96% ), but greater specificity (97 vs 59%) and a positive predictive value (60 vs 39%) in predicting successful ablation compared with JR seen only during the RF delivery. It is concluded that the presence of Post-JR might be a r eflection of the intense effect of RF energy on the nodal or peri-nodal tis sue.