Key result
ED cardioversion for acute AF is not linked to increased 30-day major events vs no cardioversion.
Why the study?
Recent guideline changes followed reports of higher-than-expected thromboembolic risk after emergency department cardioversion for acute atrial fibrillation/flutter, prompting the need to confirm whether cardioversion increases risk compared to non-conversion.
Does emergency department cardioversion increase the risk of stroke, systemic embolism, or death in patients with acute atrial fibrillation or flutter?
Cohort (n=2,521)
Yes
Does emergency department cardioversion increase the risk of stroke, systemic embolism, or death in patients with acute atrial fibrillation or flutter?
Effect estimate: ARI 0.13% (95% CI -0.36 to 0.69)
Absolute Event Rate: 0.37% vs 0.23%
Absolute Risk Reduction: -0.13%
p-value: p=.61
Emergency department cardioversion for acute atrial fibrillation or flutter is associated with a very low risk of stroke, systemic embolism, or death, which is not significantly higher than in non-cardioverted patients.
Low event rates support considering ED cardioversion for acute AF/flutter; leaves open need for randomized confirmation.
Objectives Guideline recommendations for the emergency department cardioversion of patients with acute atrial fibrillation/flutter have recently changed. This was related to several studies that found a higher-than-expected risk of subsequent stroke or systemic embolism in cardioverted atrial fibrillation/flutter patients. We sought to confirm an elevated rate of stroke, systemic embolism, or death following emergency department cardioversion to normal sinus rhythm compared with similar patients who were not converted. Methods This retrospective cohort study combined 4 datasets of atrial fibrillation/flutter patients seen at 25 emergency departments in Ontario, Canada, 2000-2012, who were all eligible for cardioversion. We linked patients to province-wide datasets to determine the primary outcome, a composite of stroke, systemic embolism, or all-cause death. To adjust for baseline differences between patients who cardioverted vs those who did not, we used overlap weights based on the propensity score. The latter included 28 variables, including oral anticoagulant prescriptions. Results Of 2521 patients, 2060 (81.7%) converted to sinus rhythm in the emergency department, and 1055 (41.8%) left on anticoagulation. Twelve (0.48%) patients met the primary outcome at 30 days and ≤5 (≤0.2%) at 7 days. In the weighted sample, at 30 days, the primary outcome occurred in 0.37% (95% CI, 0.04%-0.78%) of cardioverted patients vs 0.23% (95% CI, 0.00%-0.60%) in those not cardioverted; the absolute risk increase was 0.13% (95% CI, −0.36% to 0.69%; P = .61), and the number needed to harm was 747. Conclusion In atrial fibrillation/flutter patients eligible for cardioversion at 25 emergency departments, the rate of subsequent stroke or systemic embolism and death was very low. After adjusting for risk factors and post-conversion oral anticoagulant use, the rate of subsequent stroke and systemic embolism and death was not significantly higher in patients who cardioverted vs those who did not.
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Atzema et al. (2025) conducted a cohort in Acute atrial fibrillation or flutter (n=2,521). Cardioversion vs. No cardioversion was evaluated on Composite of stroke, systemic embolism, or all-cause death at 30 days (ARI 0.13%, 95% CI -0.36 to 0.69, p=.61). Emergency department cardioversion for acute atrial fibrillation or flutter did not significantly increase 30-day stroke, systemic embolism, or death vs no cardioversion (0.37% vs 0.23%; P=.61).
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