ABSTRACT
BACKGROUND AND OBJECTIVE: Focal sources of paroxysmal atrial fibrillation may be treatable by electrical isolation of the pulmonary veins from the left atrium. A new fiberoptic balloon catheter was tested as an alternative to radiofrequency catheter ablation for creation of circumferential thermal lesions at the pulmonary vein orifice. STUDY DESIGN/MATERIALS AND METHODS: In vitro and in vivo experiments were conducted in canine hearts to demonstrate efficacy and optimize ablation dosimetry. Continuous-wave, 1.06-microm, Nd:YAG laser radiation was delivered radially through diffusing optical fiber tips enclosed in a balloon catheter. During in vivo studies, the catheter was placed at the pulmonary vein orifice through a left atrial appendage sheath under X-ray fluoroscopic guidance during an open-chest procedure. Additionally, circumferential lesions in the left atrial appendage were correlated with epicardial electrograms demonstrating elimination of electrical activity. RESULTS: The pulmonary veins were successfully ablated by using laser powers of 30--50 W and irradiation times of 60--90 seconds. Transmural, continuous, and circumferential lesions were produced in the pulmonary veins in a single application without evidence of tissue vaporization or endothelial disruption. CONCLUSION: Laser ablation by using a fiberoptic balloon catheter may represent a promising alternative to radiofrequency catheter ablation for electrical isolation of the pulmonary veins from the left atrium during treatment of paroxysmal atrial fibrillation. Further development and testing of the fiberoptic catheter is warranted for possible clinical studies.
