Transvenous catheter cryoablation for treatment of atrial fibrillation: results of a feasibility study.

Pulmonary vein (PV) isolation using radiofrequency (RF) ablation can induce PV stenosis. Cryoablation may offer a safer alternative energy source for PV isolation. PV isolation with cryoablation was attempted in 31 patients with paroxysmal atrial fibrillation (AF). Event monitors were used to measure the AF episode burden. Serial spiral CT scans were obtained to monitor PV stenosis pre- and postcryoablation. Cryoablation was immediately successful for PV isolation in 29 of 31 patients (94%), with 5.9 +/- 1.2 months of follow-up. Additional RF ablation was performed for AF recurrences in seven patients. The remaining 22 patients with a single cryoablation procedure demonstrated a time-dependent, long-term reduction in the frequency of AF episodes. At 6 months of follow-up, 18 of 22 of cryo-treated only patients (82%) were free of symptomatic AF episodes, and antiarrhythmic drugs were discontinued in 12 of 22 patients. Serial spiral CT scans demonstrated no change in the cryo-treated PV ostial diameter. PV cryoablation was effective to control paroxysmal AF in most patients. Early recurrences of AF postcryoablation were common, though tended to resolve within 6 months postablation, consistent with a process of reverse atrial remodeling. Cryoablation of the PVs did not cause PV stenosis or other serious adverse events.