LIKELIHOOD OF SPONTANEOUS CONVERSION OF ATRIAL-FIBRILLATION TO SINUS RHYTHM

Objectives. We sought to determine the likelihood and predictors of sp ontaneous conversion to sinus rhythm of recent onset atrial fibrillati on (symptoms <72 h). Background. Although spontaneous conversion of re cent-onset atrial fibrillation is common, the likelihood and clinical and echocardiographic predictors have not been fully defined, Such dat a would be important far management of patients in whom early cardiove rsion is desired: Cardioversion could be delayed in patients with a hi gh likelihood of spontaneous conversion, and it could be expeditiously pursued if spontaneous conversion is unlikely. Methods. We screened 1 ,822 consecutive adults admitted to the hospital with atrial fibrillat ion and prospectively identified 356 patients (45% male, mean age +/- SD 68 +/- 16 years) with atrial fibrillation of <72-h duration. The oc currence of spontaneous conversion to sinus rhythm and clinical and ec hocardiographic data were identified through retrospective chart revie w. Results. Spontaneous conversion to sinus rhythm occurred in 68% of the study group (n = 242; 95% confidence interval [CI] 63% to 73%). Am ong patients with spontaneous conversion, the total duration of atrial fibrillation was <24 h in 159 (66%), 24 to 48 h in 42 (17%) and >48 h in 41 (17%) (p < 0.001). Logistic regression analysis of clinical dat a identified presentation <24 h from onset of symptoms as the only pre dictor of spontaneous conversion (odds ratio 1.8, 95% CT 1.4 to 2.4, p < 0.0001), Normal left ventricular systolic function was more common among patients with spontaneous conversion (p = 0.83), but it was not an independent predictor of conversion. Left atrial dimension was simi lar between groups. Conclusions. Spontaneous conversion to sinus rhyth m occurs in almost 70% of patients presenting with atrial fibrillation of <72-h duration. Presentation with symptoms of <24-h duration is th e best predictor of spontaneous conversion. (C) 1998 by tile American College of Cardiology.