Efficacy of multiple ring and coil electrode radiofrequency ablation catheters for the creation of long linear lesions in the atria

Atrial fibrillation is an arrhythmia that may potentially be treated by cre ating long linear lesions in the atria to create lines of electrical conduc tion block. While this has been performed with success with open-heart surg ery, it has been proposed that a less invasive catheter-based approach coul d achieve similar success. Radiofrequency energy catheter ablation was perf ormed in vivo with two novel electrode catheters. Each was an expanding loo p design: one with 3 mm ring electrodes; and one with 12.5 mm coil electrod es. Power delivery was controlled automatically with temperature (70 degree s C target) feedback from thermistors embedded in each electrode. A total o f 39 lines of ablation were created in the atria of Il normal dogs. The coi l electrodes were more effective in creating lesions than the ring electrod es with a similar prevalence of transmurality (89% vs. 85%) but a higher pr evalence of continuous transmurality (35% vs. 5%). Sequential electrode ene rgy delivery was better than simultaneous multipolar delivery due to varyin g efficiencies of tissue heating. Inadequate heating was observed in 47% of simultaneous versus 1% of sequential multipolar deliveries, and excessive heating in 6% versus 1% of cases, respectively. It is feasible to create li near atrial lesions with an expanding loop electrode catheter. Catheters wi th coil electrodes are more effective than those with ring electrodes. In o rder to avoid coagulum formation and inefficient heating, sequential electr ode energy delivery is preferable to multipolar delivery. (C) 1998 IPEM. Pu blished by Elsevier Science Ltd. All rights reserved.