Predicting spontaneous conversion to sinus rhythm in symptomatic atrial fibrillation: The ReSinus score

Background The optimal management of patients presenting to the Emergency Department with hemodynamically stable symptomatic atrial fibrillation remains unclear. We aimed to develop and validate an easy-to-use score to predict the individual probability of spontaneous conversion to sinus rhythm in these patients Methods This retrospective cohort study analyzed 2426 cases of first-detected or recurrent hemodynamically stable non-permanent symptomatic atrial fibrillation documented between January 2011 and January 2019 in an Austrian academic Emergency Department atrial fibrillation registry. Multivariable analysis was used to develop and validate a prediction score for spontaneous conversion to sinus rhythm during Emergency Department visit. Clinical usefulness of the score was assessed using decision curve analysis Results 1420 cases were included in the derivation cohort (68years, 57-76; 43% female), 1006 cases were included in the validation cohort (69years, 58-76; 47% female). Six variables independently predicted spontaneous conversion. These included: duration of atrial fibrillation symptoms (<24hours), lack of prior cardioversion history, heart rate at admission (>125bpm), potassium replacement at K + level ≤3.9mmol/l, NT-proBNP (<1300pg/ml) and lactate dehydrogenase level (<200U/l). A risk score weight was assigned to each variable allowing classification into low (0-2), medium (3-5) and moderate (6-8) probability of spontaneous conversion. The final score showed good calibration (p=0.44 and 0.40) and discrimination in both cohorts (c-indices: 0.74 and 0.67) and clinical net benefit Conclusion The ReSinus score, which predicts spontaneous conversion to sinus rhythm, was developed and validated in a large cohort of patients with hemodynamically stable non-permanent symptomatic atrial fibrillation and showed good calibration, discrimination and usefulness Registration NCT03272620