Sex, age, and time to cardioversion. Risk factors for cardioversion of acute atrial fibrillation from the FinCV study.

BACKGROUND

Female sex, old age, and time to cardioversion increase the risk of thromboembolic complications (TEC) after cardioversion of atrial fibrillation (AF) < 48 h. The interaction of these variables is not known. We investigated the interaction of sex, age, and time to electrical cardioversion (ECV) on TEC in anticoagulant-naive patients with acute AF.

METHODS AND RESULTS

The primary outcome was a TEC within 30 days following ECV. Patients were divided into three age groups and time to cardioversion into <12 h and ≥12 h in 4715 ECVs. TEC occurred in 40 (0.8%) patients. In multivariate analysis, female sex, time to ECV, and vascular disease were independent predictors of TEC. For patients ≤75 cardioverted within 12 h, the incidence of TEC was low. In patients >75 TEC increased in both sexes and particularly in women (1.4% vs. 0.9%, p = 0.03). When ECVs exceeded 12 h, the risk of TEC was two- to four-fold higher in women in all age groups.

CONCLUSIONS

The risk of TEC increases substantially in patients >75 and ECVs ≥12 h, particularly in women. Time to cardioversion should be added to risk-stratification of ECVs of acute AF. Key messages The ideal timing of cardioversion is still unknown and not based on solid evidence. Delay to cardioversion ≥12 h should be added to the risk stratification of atrial fibrillation cardioversion. Female sex increases the risk of complications and failure of cardioversion after electrical cardioversion of atrial fibrillation <48 h, especially with age >75 years and time to cardioversion exceeding 12 h.