Predictors and timeline of spontaneous conversion to normal sinus rhythm: A single center retrospective cohort study of patients with symptomatic atrial fibrillation.

Introduction: Annual healthcare expenditures associated with atrial fibrillation (AF) in the United States (US) continue to grow as more symptomatic patients present to emergency departments (ED). Predictors of spontaneous conversion to normal sinus rhythm (ScNSR) remain poorly understood, as well as the timeline of ScNSR remains unclear. We sought to 1) to assess the association of key demographics, anthropometric, and clinical factors to ScNSR and 2) to evaluate the timeline of ScNSR, and 3) determine clinical predictors of ScNSR.

Methods: This single center, retrospective cohort study analyzed patients aged ≥18 years with symptomatic AF as diagnosed and evaluated through the ED of a rural tertiary care center in West Virginia from September 2015 to December 2018.

Results: Our cohort consisted of 375 AF patients (mean age 65 years, 54% male). A total of 177 patients attained ScNSR either in the ED or after hospital admission with a mean conversion time of 14.7 h (±12). Onset of symptoms <24 hrs has strong positive association to ScNSR 3.97 (95% CI: 2.24-7.05; p < 0.0001). Male gender 0.55 (95% CI: 0.35-0.85; p = 0.007) and hypertension 0.48 (95% CI: 0.31-0.76; p = 0.002), showed a strong negative association to ScNSR. Of the patients that converted spontaneously (177), the majority, 136 (76.8%) achieved ScNSR within 24 h of ED triage without use of electrical or chemical cardioversion.

Conclusion: Most patients with AF in the ED converted spontaneously to sinus rhythm within the first 24 h which underscores the importance of earlier watchful waiting over interventions to achieve normal sinus rhythm (NSR).