Efficacy and safety of antiarrhythmic drugs for pharmacological cardioversion of atrial fibrillation depending on gender: a subanalysis of CANT II Study

Abstract Background/introduction The data on gender differences concerning antiarrhythmic drugs (AAD) applied in atrial fibrillation (AF) patients is scarce. Purpose The aim of the study was to evaluate gender differences in terms of clinical profile of AF patients, and efficacy and safety of AAD used for pharmacological cardioversion (PCV) of AF. Methods This research was a sub-analysis of retrospective multicenter Cardioversion with ANTazoline II (CANT) registry, which comprised 1365 patients with short-duration AF referred for urgent PCV with the use of AAD. Patients were categorized in terms of gender and compared in terms of clinical parameters and outcome of PCV. The primary endpoint was return of sinus rhythm within 12 hours after drug infusion and the composite safety endpoint involved bradycardia <45 bpm, hypotension, syncope or death. Results The majority of patients qualified for PCV were men (n=725, 53.1%). Females were older and more symptomatic, had higher CHA2DS2-VASc score, greater prevalence of tachyarrhythmia and higher utilization of chronic anticoagulation. The overall efficacy (71.4% vs. 70.1%,P=0.588) and safety (5.2% vs. 4.6%,P=0.603) of PCV was comparable in men and women. Amiodarone (68.3% vs. 65.9%, P=0.664) and antazoline (77.1% vs. 80.0%, P=0.19) had similar efficacy in men and women, but propafenone had lower rate of rhythm conversion in men (64.7% vs. 79.3%, P=0.046; Figure). None of the assessed AAD differed in terms of safety profile in both genders. Logistic regression showed that, among other predictors, in women the use of amiodarone vs. other AAD (odds ratio [OR] 0.569, P=0.033), while in men administration of a amiodarone (OR 0.379, P=0.001) or propafenone (OR 0.331, P=0.002) vs. other AAD were associated with lower chance of successful rhythm conversion. Conclusions Female patients with AF share different clinical profile and similar efficacy and safety of AAD used for PCV as compared to male participants. Propafenone has significantly lower efficacy in men, which requires further prospective investigation.