Atrial fibrillation (AF) and acute heart failure (AHF) are two closely interrelated conditions that frequently coexist in a manifold manner, with AF serving either as the causative factor or as the consequence or even as an innocent bystander. The interplay between these two clinical conditions is complex, given that they share common pathophysiological pathways and they can reciprocally exacerbate each other, thus triggering a vicious cycle that worsens the prognosis and increases the thromboembolic risk. The optimal management of AF in the context of AHF in the emergency department remains a challenge depending on the time onset, as well as the nature and the severity of the associated symptoms. Acute rate control, along with early rhythm control, when indicated, and anticoagulation represent the main pillars of the therapeutic intervention. The purpose of this review is to elucidate the pathophysiological link between AF and AHF and accordingly present a stepwise algorithmic approach for the management of AF in AHF patients in the emergency setting.

Background: Atrial fibrillation (AF) is a common arrhythmia in the emergency department (ED). We investigated the role of N-terminal pro b-type natriuretic peptide (NT-proBNP) in predicting both the outcome of AF cardioversion and the risk of AF recurrence or persistence on the 8th (D8) and 30th (D30) day post-cardioversion. Methods: This prospective, observational study evaluated patients with recent-onset AF, managed by either pharmacological (PC) or electrical cardioversion (EC) in the ED. Patients were treated either immediately or electively after 3 weeks of anticoagulation. NT-proBNP assessments were performed prior to cardioversion. Results: Of the 148 patients enrolled, 56% had paroxysmal AF, 85% underwent immediate cardioversion and 72% received EC. Successful cardioversion to sinus rhythm (SR) was achieved in 85% of patients. Patients with successful cardioversion and those who remained free from AF on D8 had lower NT-proBNP levels compared to patients with failed cardioversion or with AF recurrence or persistence on D8 [day of cardioversion, D0: SR vs. non-SR, 387 (127–1095) pg/mL vs. 1262 (595–2295), p = 0.004; D8: SR vs. non-SR, 370 (127–1095) vs. 1366 (718–2295), p = 0.002]. In multivariate analysis, higher logNT-proBNP was associated with higher risk of cardioversion failure [OR, 95%CI: 4.80 (1.58–14.55), p = 0.006] and AF recurrence or persistence on D8 [OR, 95%CI: 3.65 (1.06–12.59), p = 0.041]. ROC analysis confirmed the predictive ability of NT-proBNP for both outcomes (D0: AUC 0.735, p < 0.001; D8: AUC 0.761, p < 0.001). A cut-off value of NT-proBNP > 580 pg/mL was able to predict failure of AF conversion and occurrence of recurrent/persistent AF at D8. Conclusions: NT-proBNP is a promising biomarker for identifying patients presenting to the ED with recent-onset AF who run a greater risk of cardioversion failure and post-discharge AF recurrence/persistence in the immediate and short term.