Safety and efficacy of electrical cardioversion of atrial fibrillation in the emergency department (HEROMEDICUS study)

Introduction

Atrial fibrillation (AF) accounts for 1% of emergency department (ED) visits of a general hospital. AF management in the ED varies from country to country and the lack of specific guidelines justifies the use of a conservative rather than a more aggressive strategy.

Purpose

In the HEROMEDICUS study we developed a protocol for the treatment of these patients in the acute phase. The protocol includes an aggressive electrophysiologist-guided rhythm control strategy for patients presenting with AF in the ED. In the present study, the final endpoint is the safety and efficacy of electrical reduction of AF in the Emergency Department.

Methodology: All patients who visited the ED from September 2023 to October 2025 due to AF or atrial flutter were tested for possible inclusion in the protocol. Those with a history of coronary heart disease as well as those with a known history of heart failure or with symptoms of acute heart failure or with evidence of acute coronary syndrome were excluded. With the use of tablet and an application designed specifically for this protocol, there was continuous counseling by a specialist electrophysiologist. In case of AF cardioversion failure with intravenous flecainide, or on contraindication of intravenous flecainide use (prior home loading with >300mg propafenone or >200mg flecainide), electrical cardioversion was performed in properly anticoagulated patients. According to institutional protocol this was performed in the absence of anesthesiologist by trained cardiologists in Advanced Life Support without the use of transesophageal echocardiography with the patient fasting for 6 hours and with sedation and analgesia administration (midazolam IV & analgesics IV) followed by biphasic synchronous current administration.

Results

From the period 08/09/2023 to 10/10/2025, 215 cases visit the Emergency Department of our hospital, of which 15 had atrial tachycardia, 28 had atrial flutter and 234 had atrial fibrillation. The mean age was 71.3±5.7 years (53% female). 130 patients had their first episode of arrhythmia. The mean CHA2DS2-VASc score was 2.2 ±0.1 and the mean ventricular frequency was 120 ± 3.58.

In 112 out of 116 patients electrical cardioversion was successful. In the remaining 4 patients a rate control strategy was initially applied. No patients experienced rhythm or anesthesia disturbances. A total of 264 out of 277 patients were discharged from the ED with a scheduled referral to the outpatient AF clinic.

Conclusion

The implementation of the HEROMEDICUS protocol in the Emergency Department shows that electrical cardioversion is safe and effectively and significantly reduces admissions from the ED of patients who present with AF.