Introduction
Pulmonary vein isolation (PVI) is an effective rhythm control therapy for atrial fibrillation (AF).1,2 However, procedure-related complications still cannot be ignored and thromboembolic complications remain a major limitation of AF ablation. Patients undergoing AF ablation are at a higher risk of intra- and post-procedural thromboembolic events; therefore, peri-procedural anticoagulation is necessary. Since non-vitamin K oral anticoagulants (NOACs) have been commonly used for stroke prevention of AF, recent studies examined the peri-procedural management of NOACs in patients scheduled to undergo radiofrequency catheter ablation (RFCA) for AF.3-6 Based on these results, the performance of the ablation procedure without interruption of oral anticoagulant (OAC) is recommended for patients undergoing AF ablation who have been therapeutically anticoagulated with OAC including NOACs.7
In terms of intra-procedural anticoagulation management, unfractionated heparin should be administered prior to or immediately following transseptal puncture and dose adjustment is recommended to achieve and maintain an activated clotting time (ACT) of at least 300 s.8 However, this recommendation is based on results of studies conducted using vitamin K antagonists (VKA) in a setting of point-by-point AF ablation. Moreover, the majority of recommendations were made based on results from studies evaluating the efficacy and safety of RFCA and not on diverse modalities for AF ablation. Several modalities use different energy sources to achieve PVI. Cryoballoon ablation (CBA), a balloon-based single shot technique for PVI, has shown the similar efficacy and safety profile with a relatively short learning curve compared to RFCA.9-13 Previous randomized clinical trials (RCTs) demonstrated that CBA had a shorter procedure time and lower rates of re-hospitalization, cardioversion, and repeat ablation than RFCA. Therefore, the use has exponentially increased.
The use of adequate peri-procedural anticoagulation regimens that strike a balance between the benefit of blood thinning and the risk of bleeding is essential in patients undergoing AF ablation. However, no data have been available in terms of anticoagulation strategy during CBA for patients who received uninterrupted NOACs. We aimed to investigate the safety of a simple anticoagulation strategy using a single bolus administration of heparin without ACT monitoring compared to that of the conventional approach using ACT-guided heparin administration in patients who underwent CBA with uninterrupted NOACs.