724-1 Characteristics of Successful Posterior Septal Sites to Cure Atrioventricular Node Reentry Using a Thermistor Controlled Catheter System

Abstract

We prospectively investigated in 55 pts characteristics of successful radiofrequency ablation (RFA) sites to cure AVN reentry (AVNRT) using a thermistor tipped catheter system with a posterior (slow pathway) approach. RFA success (S) was ≤ 0:2 AVNRT echos after RFA; only 1 pt had AVNRT at follow-up. There were 166 RFA [55 S; 111 failure (F)], with 3 ± 3/pt. Local atrial electrogram morphology was-A (low to isoelectric to high frequency); B (low to high frequency); and C(≥ 2 high frequency components). Differences with S vs F, respectively. are: atrial amplitude (396 ± 181 vs 357 ± 205 μV P < 0.001); ventricular amp. (3.0 ± 1.6 vs 2.7 ± 1.6 mV, p < 0.001); time to onset of junctional tachycardia (JT) (2.1 ± 1.9 vs 4.6 ± 6.1 sec, p < 0.05); duration of JT 1146 ± 8.6 vs 11.6 ± 7.7 sec, p < 0.001); CL of JT(481 ± 92vs 511 ± 120 ms, p < 0.0011; and change in CL of JT during RFA (–34 ± 113 vs + 23 ± 128 ms, p < 0.03). Of note, continuous JT was more common at S sites (46% vs 21%), and JT occurred in:≤ 7.5 sec at all S sites. No differences between Svs F were in: power(46.8 ± 7.5 vs 44.5 ± 8.6 W); catheter tip temp. (52.6 ± 4.6 vs 49.3 ± 5.5°C); atrial electrogram duration (66 ± 20 vs 66 ± 19 ms); ortype of local atrial electrogram. We conclude: 1) Successful RFA to cure AVNRT more frequently occurs with rapid onset of continuous junctional tachycardia with a CL that shortens before termination and, 2) there is no specific local atrial electrogram morphology that predicts success.