Abstract 15276: Electro-Anatomic Characteristics of Successful Applications With 8 mm-Tip Cryocatheter in Young Patients With Atrioventricular Nodal Reentrant Tachycardia
Background: An 8 mm-tip cryocatheter (8 mm-Cryo) has been employed to improve long-term efficacy for ablation of AV nodal reentrant tachycardia (AVNRT). We hypothesized that the local electrogram signal at sites of success would require a larger atrial component due to the larger catheter tip. This is the first study to delineate the anatomic and intracardiac electrogram correlates for successful ablation sites using this catheter.
Methods: This study included 34 young patients undergoing cryoablation for AVNRT from 2010- 2012 (19 female, age 18±3.8 years). Ablation was performed in a step-wise fashion moving superiorly starting at the level of the floor of CS. Success was defined as loss of slow AV node pathway conduction within 30 seconds. Anatomic locations were recorded by EnSite NavX™ mapping system. The ratio of local atrial to ventricular electrogram amplitudes (A:V ratio) and time to achieve tip temperature of -30o C (T30) and -80o C (T80) were evaluated.
Results: A total of 115 cryo-applications (46=successful, 69=unsuccessful) were analyzed. The mean A:V ratio of successful applications was significantly higher (0.71±0.74 vs. 0.38±0.35; p<0.01) than unsuccessful adjacent applications (Fig 1A). The T30 and T80 were not different for successful vs. unsuccessful applications (11±2 vs. 10±3 sec; p=0.38 and 22.5±5 vs. 23±5 sec; p=0.86, respectively). The most common site of success was anterior to roof of CS os (Fig 1B). Acute success was achieved in all patients without AV block. Only one patient had recurrence of AVNRT during mean follow-up 6 (3-13) months.
Conclusions: This is the first study to describe the electro-anatomic characteristics of cryoablation utilizing an 8 mm-tip Cryo in young patients with AVNRT. The majority of successful sites were anterior to the roof of the CS os. The A:V ratio at sites of success was higher than that compared to unsuccessful sites and to that reported using a standard 4 mm-tip catheter.
- © 2013 by American Heart Association, Inc.