title: Spontaneous conversion of patients with atrial fibrillation scheduled for electrical cardioversion: an ACUTE trial ancillary study.
abstract: OBJECTIVE
  This study was designed to determine the characteristics and outcomes of spontaneous conversion (SC) to sinus rhythm (SR) in patients with atrial fibrillation (AF) of more than two days.
  
  
  BACKGROUND
  The Assessment of Cardioversion Using Transesophageal Echocardiography (ACUTE) multicenter study was a prospective trial in which transesophageal echocardiography (TEE)-guided treatment was compared with conventional anticoagulation treatment for the management of patients with AF >2 days undergoing direct current cardioversion (DCC). In an ancillary analysis, we evaluated the baseline and outcome data in patients who underwent SC to SR before scheduled DCC.
  
  
  METHODS
  We identified 1,041 patients for this analysis after excluding patients on pre-existing antiarrhythmic agents. Patients with SC in the TEE-guided and conventional groups were first compared then pooled and compared with non-spontaneous conversion (No-SC) patients.
  
  
  RESULTS
  Overall, 167 of 1,041 (16%) patients underwent SC, with twice as many in the conventional compared with the TEE-guided group (110/523 [21%] vs. 57/518 [11%]; p < 0.001). When compared with No-SC patients, a higher proportion of SC patients maintained SR at eight weeks (87.2% vs. 48.9%, p < 0.001), without statistically significant differences in bleeding, thromboembolism or mortality. Multivariate predictors of SC were shorter duration of AF, New York Heart Association (NYHA) functional class 1 or 2, smaller left atrial size, and absence of left atrial spontaneous echo contrast.
  
  
  CONCLUSIONS
  Spontaneous conversion was associated with shorter duration of AF, lower NYHA class, smaller left atrial size, and absence of left atrial spontaneous echo contrast. There was a better SR outcome in the SR group, but no differences in the other clinical end points. The conventional treatment strategy allowed greater opportunity for SC. In the absence of favorable predictors of SC, the TEE-guided approach should be considered.
authors: Department of Cardiovascular Medicine, Cleveland Clinic Foundation, Ohio 44195, USA.
authors: S Ahmed
authors: SA
authors: Tejan-Sie
authors: R Daniel
authors: RD
authors: Murray
authors: Ian W
authors: IW
authors: Black
authors: Susan E
authors: SE
authors: Jasper
authors: Carolyn
authors: C
authors: Apperson-Hansen
authors: Jianbo
authors: J
authors: Li
authors: Elizabeth A
authors: EA
authors: Lieber
authors: Richard A
authors: RA
authors: Grimm
authors: Allan L
authors: AL
authors: Klein
mesh_terms: D001281:Atrial Fibrillation / Q000000981:diagnostic imaging / Q000503:physiopathology; D017548:Echocardiography, Transesophageal; D004554:Electric Countershock; D016015:Logistic Models; D011446:Prospective Studies; D012372:ROC Curve; D016032:Randomized Controlled Trials as Topic; D012075:Remission, Spontaneous