Usefulness of the Steerable Sheath for the Isthmus Ablation

Abstract

Background: To establish the conduction block of the atrial isthmus, especially in MI (mitral isthmus) is often difficult and challenging even with the guide of long-sheath. We investigated the usefulness of a steerable sheath for CTI (cavo-tricuspid isthmus) and MI ablation. Methods: A total of 40 and 80 consecutive patients undergoing CTI and MI ablation, respectively, were randomized to one of the following two groups: group S (using a steerable long-sheath) or group NS (non-steerable long-sheath). CTI and MI ablation was performed by using the 8-mm tip and the open-irrigated catheter, respectively. The endpoint of isthmus ablation was the achievement of a bidirectional block. Results: CTI-block was achieved in all patients. The duration and total amount of radiofrequency energies were significantly shorter and smaller in group S than in group NS (310±193 vs. 661±504 seconds, P=0.006 and 12197±7306 vs. 26906±21238 joules, P=0.006). As for the MI ablation, bidirectional block was achieved in 87.5% (70/80) of patients with 14.0±6.7 minutes of radiofrequency application. The MI-block was more frequently achieved in group S compared to NS (97.5% (39/40) vs. 77.5% (31/40), P=0.02). Additionally, epicardial ablation within the CS was less frequently required in group S compared to NS (12.5% (5/40) vs. 72.5% (29/40), P<0.0001). Conclusions: Use of a steerable sheath was useful for both CTI and MI ablation by either reducing the amount of energy required or increasing the success rate with less needs of epicardial ablation.