Usability of CHA2DS2VASC score in predicting the effectiveness and safety of pharmacological cardioversion – data from the multicenter Cardioversion with intravenous ANTazoline (CANT Study) study

Bartosz Krzowski^1*Krzysztof Ozierański¹Michał Peller¹Wojciech Wróbel²Dawid Miśkowiec³Edyta Ćwiek-Rębowska³Aleksander Maciąg⁴Michal Farkowski⁵Marek Szołkiewicz⁶Beata Ceynowa-Sielawko⁶Marek Koziński⁷Maciej Wójcik⁸Robert Błaszczyk⁸Hanna Szwed⁴Jaroslaw Kasprzak³Katarzyna Mizia-Stec²Maciej Wybraniec²Paweł Balsam¹

• ¹Warszawski Uniwersytet Medyczny, Warsaw, Poland
• ²Slaska Akademia Medyczna w Katowicach, Katowice, Poland
• ³Uniwersytet Medyczny w Lodzi, Łódź, Poland
• ⁴National Institute of Cardiology, Warsaw, Poland
• ⁵Panstwowy Instytut Medyczny Ministerstwa Spraw Wewnetrznych i Administracji, Warsaw, Poland
• ⁶Department of Cardiology and Angiology, Kashubian Center for Heart and Vascular Diseases, Wejherowo, Poland
• ⁷Gdanski Uniwersytet Medyczny, Gdańsk, Poland
• ⁸Uniwersytet Medyczny w Lublinie, Lublin, Poland

Background: Pharmacological cardioversion (PCV) is one of the therapeutic options within rhythm control strategies for atrial fibrillation (AF). Data on clinical determinants influencing its effectiveness and safety in real-world settings remain limited. Methods: This study is a sub-analysis of the multicenter Cardioversion with Intravenous Antazoline in Atrial Fibrillation II (CANT II) registry. The registry retrospectively included consecutive patients with recent-onset AF undergoing urgent PCV in six Polish centers between 2019–2020. We analyzed 931 patients stratified according to CHA₂DS₂-VASc score: Group I (0–1 points; n=194), Group II (2–4 points; n=580), and Group III (≥5 points; n=157). The primary endpoint was successful restoration of sinus rhythm within 12 h, and the secondary endpoint was a composite of adverse events (death, syncope, bradycardia, hypotension). Results: The median age was 69 years, 48% were men, and the median CHA₂DS₂-VASc score was 3. Antazoline was used in 59% of patients, amiodarone in 53%, and propafenone in 19%. Sinus rhythm was restored in 69%, 70%, and 64% of patients in Groups I, II, and III, respectively (p=0.45). The overall adverse event rate was low (2.1%) and did not differ significantly between groups (p=0.16). Antazoline was most effective in Group I, while propafenone showed higher efficacy in Group II. Conclusions: In this retrospective sub-analysis of the CANT II registry, success of pharmacological cardioversion of AF is not associated with number of comorbidities as assessed by the CHA2DS2VASc score. PCV remains a feasible and generally safe option in emergency and cardiology department practice.