Laser ablation of the pulmonary veins by using a fiberoptic balloon catheter: Implications for treatment of paroxysmal atrial fibrillation

Background and Objective: Focal sources of paroxysmal atrial fibrillation m ay be treatable by electrical isolation of the pulmonary veins from the lef t atrium. A new fiberoptic balloon catheter was tested as an alternative to radiofrequency catheter ablation for creation of circumferential thermal l esions at the pulmonary vein orifice. Study Design/Materials and Methods: In vitro and in vivo experiments were c onducted in canine hearts to demonstrate efficacy and optimize ablation dos imetry. Continuous-wave, 1.06-mum, Nd:YAG laser radiation was delivered rad ially through diffusing optical fiber tips enclosed in a balloon catheter. During in vivo studies, the catheter was placed at the pulmonary vein orifi ce through a left atrial appendage sheath under X-ray fluoroscopic guidance during an open-chest procedure. Additionally, circumferential lesions in t he left atrial appendage were correlated with epicardial electrograms demon strating elimination of electrical activity. Results: The pulmonary veins were successfully ablated by using laser power s of 30-50 W and irradiation times of 60-90 seconds. Transmural, continuous , and circumferential lesions were produced in the pulmonary veins in a sin gle application without evidence of tissue vaporization or endothelial disr uption. Conclusion: Laser ablation by using a fiberoptic balloon catheter may repre sent a promising alternative to radiofrequency catheter ablation for electr ical 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. (C) 2001 Wi ley-Liss, Inc.