Clinical Utility of Intravenous Nifekalant Injection During Radiofrequency Catheter Ablation for Persistent Atrial Fibrillation.

Background: Radiofrequency catheter ablation (RFCA) for persistent atrial fibrillation (AF) is still challenging even in RFCA-era for AF. The aim of this study was to assess the clinical utility of nifekalant, a pure potassium channel blocker,during RFCA for persistent AF. Methods and Results: We retrospectively enrolled 157 consecutive persistent AF patients undergoing first RFCA procedure with complex fractionated atrial electrogram (CFAE) ablation after pulmonary veins isolation and compared outcomes between patients with (NFK group: N=79) and without (No-NFK group: N=78) additional CFAE ablation using intravenous nifekalant (0.3mg/kg). Primary endpoint was 24-month atrial arrhythmia-free survival post ablation.The prevalence of AF termination was significantly higher in NFK group than No-NFK group (64.6% versus 7.7%, P<0.001). Arrhythmia-free survival, however, was not significantly different between 2 groups (61.5% versus 54.1%, P=0.63).There was no significant difference between 2 groups in the prevalence of recurrent atrial tachycardia (25.0% versus 23.5%, P=0.89). Arrhythmia-free survivalin patients with AF termination during procedure was significantly higher than those without (73.0% versus 41.0%, P=0.002; adjusted hazard ratio 0.48, 95% confidence interval 0.17-0.84, P=0.02) among NFK group,but not among No-NFK group (66.7% versus 53.2%, P=0.53). Conclusions: Intravenous nifekalant injection during additional CFAE ablation did not improve sinus maintenance rate after RFCA procedure for AF, but AF termination by nifekalant injection could be a clinical predictor of better success rates after procedure. [ABSTRACT FROM AUTHOR]