Cryoablation of the pulmonary veins using a novel balloon catheter.

Abstract

INTRODUCTION: Pulmonary vein (PV) isolation has emerged as a promising technique for the treatment of patients with drug-refractory atrial fibrillation, however, the achievement of transmural lesions has remained a challenge. We evaluated the ability of a novel balloon-based cryogenic catheter system in achieving transmural lesions for PV isolation. METHODS: Six pulmonary vein ostia from three excised ovine hearts and lungs were used in this study. The balloon catheter was deployed and positioned at the ostia of the PVs and a full 8-minute ablation was then performed, while the heart was bathed in a circulating bath of normal saline at 37 degrees. Thermocouples positioned on the endocardial (balloon surface-tissue interface) and epicardial surfaces of the ostia were used to determine whether transmural freezing was achieved. RESULTS: The mean temperatures measured on the endocardial and epicardial tissue in six PV ablations were -38.8 +/- 6.9 degrees C and -10.0 +/- 7.5 degrees C, respectively. The average pulmonary vein thickness was 3.3 +/- 1.4 mm. CONCLUSIONS: A novel cryoablation balloon catheter is capable of achieving transmural freezing of the pulmonary vein. The catheter has promise for future clinical therapy of atrial fibrillation.