Pulmonary Vein Isolation Using a Second-Generation Cryoballoon Catheter: A Randomized Comparison of Ablation Duration and Method of Deflation
The study was funded by a research grant from Medtronic, Inc.
Dr. Khairy is supported by a Canada Research Chair in Electrophysiology and Adult Congenital Heart Disease.
J.G. Andrade received compensation from Medtronic for participation on a speaker's bureau relevant to this topic. M. Talajic served on a Medtronic advisory board. M. Dubuc received honoraria relevant to this topic and served as consultant/advisory board member of an unnamed company. P. Guerra received compensation for participation on a speaker's bureau and served on advisory board of an unnamed company. N. Coulombe is an employee of Medtronic, Inc.
Address for correspondence: Dr. Paul Khairy, M.D., Ph.D., Electrophysiology Service, Montreal Heart Institute, 5000 Belanger St. E, Montreal, QC, Canada, H1T 1C8; Fax: 514-593-2581; E-mail: firstname.lastname@example.org
Ablation Time and Active Cryoballoon Deflation
Optimal cryoballoon ablation parameters for pulmonary vein (PV) isolation remain to be defined. We conducted a randomized preclinical trial to compare 2- versus 4-minute ablation lesions and assess the safety of active (forced) cryoballoon deflation.
Methods and Results
Thirty-two dogs underwent PV isolation with a second-generation 23 mm cryoballoon catheter. The left superior (LSPV) and inferior (LIPV) PVs were randomized in a factorial design to (1) a single 2- versus 4-minute cryoapplication, and (2) passive versus active cryoballoon deflation. Animals were survived for 30 days, after which histopathologic analysis was performed. Acute PV isolation was attained in 89.8% of PVs after a single application (93.8% LSPV, 85.2% LIPV; P = 0.2823). Mean time to PV isolation was 29.5 ± 18.5 seconds. Although 4-minute lesions were associated with a thicker neointima than 2-minute lesions (223.8 μm versus 135.6 μm; P = 0.007), no differences were observed in procedural characteristics (freezing temperature, rewarming time), rates of acute PV isolation, or the achievement of complete circumferentially transmural lesions at 30 days (78.7% overall; 86.2% for 2 minutes vs 70.0% for 4 minutes; P = 0.285). Active deflation was associated with faster balloon rewarming but not with significant differences in mean or maximum neointimal thickness.
A single application with the second-generation cryoballoon catheter results in a high rate of PV isolation. The degree of vascular injury was not increased by active balloon deflation and no differences in acute efficacy or mature transmural circumferential lesions were observed with 2- versus 4-minute applications.