Using the pre-freezing technique results in a wider area of antral isolation during cryoballoon pulmonary vein isolation in patients with atrial fibrillation

The “pre-freezing” technique was a method in which a fully inflated balloon after the start of freezing was pressed against the pulmonary vein (PV) during cryoballoon ablation and has been applied especially in large-size PVs. Of 556 patients who underwent cryoballoon ablation for atrial fibrillation (AF), the pre-freezing technique was applied to 48 patients. The resulting 2:1 propensity score-matched data set included 120 patients. Using the pre-freezing technique, all left-superior PVs, all left-inferior PVs, and 95% of right-superior PVs were successfully isolated. In most right-inferior PVs, complete sealing using the pre-freezing technique was challenging, and this technique was not applied. Procedure time was similar between the two groups. In the pre-freezing group, the percentage of the left atrial posterior wall isolated was larger (47.6 ± 10.3 vs. 42.8 ± 15.7%, P = 0.006), and the postoperative reduction of diaphragmatic compound motor action potentials tended to occur less frequently (2.5 vs. 12.5%, P = 0.07), and the reduction of the cross-sectional LSPV area was smaller (17.5 ± 12.2 vs. 27.2 ± 19.8%, P = 0.03) than the conventional group. The AF-free rate of the two groups was similar between the two groups (P = 0.15). The pre-freezing technique was a simple method that can isolate a wider surface area during cryoballoon PV isolation. While the postoperative AF recurrence was comparable, the postoperative reduction in the cross-sectional PV area was less than that of the conventional method, which may reduce the risk of PV stenosis.