Cooled ablation reduces pulmonary vein isolation time: results of a prospective randomised trial

Background: Currently, selection of the ablation catheter for pulmonary vein (PV) isolation is a matter of choice. Objective: To evaluate the efficiency of cooled ablation for PV isolation. Methods: A prospective randomised trial was carried out comparing the time required to disconnect each targeted PV using cooled ablation (open irrigation at 15 ml/min, group A) or standard temperature-controlled 4 mm tip catheter ablation (group B). The ablation parameter limit settings were 45°C, 35 (5) W in group A, and 55°C, 35 (5) W in group B. Results: Thirty-six patients referred for a first atrial fibrillation (AF) ablation procedure were randomised to group A or group B (18 patients in each group). There were no significant differences in baseline characteristics between the groups. Bidirectional block was achieved in 61/61 PVs from group A (100%) and 59/61 PVs from group B (97%); p = NS. Time to PV disconnection was significantly shorter in group A than in group B (median (25th–75th centiles) 14 (5–28) min vs 19 (14–32) min, respectively; p  =  0.003). Five asymptomatic PV stenoses were identified by MRI, all in group B (p = 0.05). After 1-year minimum follow-up, AF recurrences were less frequently documented in patients treated with cooled ablation (6% vs 33%; p = 0.05). Conclusion: Cooled ablation is more efficient than standard ablation in achieving PV isolation. Results obtained from this study also suggest a potential benefit of clinical efficacy and safety from cooled ablation, which should be further evaluated in larger clinical trials.