Thromboembolisms related to post-operative electrical cardioversions for atrial fibrillation in patients with surgical aortic valve replacement

Aims: Post-operative atrial fibrillation (POAF) is a frequent complication after open-heart surgery, and cardioversions (CV) are commonly performed to restore sinus rhythm. However, little data exists on thrombo-embolic risk related to early post-operative CV and on the recurrence of POAF after CV. CAREAVR study sought to assess the rate of strokes, transient ischaemic attacks (TIA), and mortality shortly after POAF-triggered CV in patients who underwent isolated surgical aortic valve replacement (SAVR) with a bioprosthesis. Methods and results: Altogether 721 patients underwent isolated SAVR with a bioprosthesis at four Finnish university hospitals. During post-operative hospitalization, after patients with prior chronic AF were excluded, 309/634 (48.7%) of patients had at least one episode of POAF [median time (interquartile range) 3 (3) days], and an electrical CV was performed in 113/309 (36.6%) of them. The length of hospital stay was not affected by CV. At 30 days follow-up, the rate of stroke, TIA or mortality was higher in those AF patients who underwent CV vs. those who did not (9.7% vs. 3.6%, P = 0.04, respectively; adjusted hazard ratio 2.63, 95% confidence interval 1.00-6.92, P = 0.05). Similar proportion of patients in both groups were in AF rhythm at discharge (32.7% vs. 35.7%, P = 0.18); and at 3 months (25.0% vs. 23.6%, P = 0.40), respectively. Conclusion: In this real-world population of patients undergoing isolated SAVR, the rate of POAF was nearly 50%. One-third of these patients underwent an electrical CV, and they exhibited over two-fold risk for thromboembolisms and mortality. Cardioversion did not affect the short-term prevalence of AF.