Background:Pulmonary vein (PV) occlusion generally depends on repetitive contrast agent injection when cryoballoon ablation for atrial fibrillation (AF).The present study was to compare the effect of cryoballoon ablation for AF guided by transesophageal echocardiography (TEE) vs.contrast agent injection.Methods:Eighty patients with paroxysmal AF (PAF) were enrolled in the study.About 40 patients underwent cryoballoon ablation without TEE (non-TEE group) and the other 40 underwent cryoballoon ablation with TEE for PV occlusion (TEE group).In the TEE group during the procedure,PVs were displayed in 3-dimensional images to guide the balloon to achieve PV occlusion.The patients were followed up at regularly scheduled visits every 2 months.Results:No differences were identified between the groups in regard to the procedure time and cryoablation time for each PV.The fluoroscopy time (6.7 ± 4.2 min vs.17.9 ± 5.9 min,P ＜ 0.05) and the amount of contrast agent (3.0 ± 5.1 mL vs.18.1 ± 3.4 mL,P ＜ 0.05) in the TEE group were both less than the non-TEE group.At a mean of 13.0 ± 3.3 mon follow-up,success rates were similar between the TEE group and non-TEE group (77.5％ vs.80.0％,P=0.88).Conclusions:Cryoballoon ablation with TEE for occlusion of the PV is both safe and effective.Less fluoroscopy time and a lower contrast agent load can be achieved with the help of TEE for PV occlusion during procedure.