title: Low atrial fibrillatory rate is associated with spontaneous conversion of recent-onset atrial fibrillation.
abstract: OBJECTIVE
  Atrial fibrillatory rate (AFR) is considered a non-invasive index of atrial remodelling. Low AFR has been associated with favourable outcome of interventions in patients with persistent atrial fibrillation (AF). However, AFR has never been studied in unselected patients with short duration of AF, prone to regain sinus rhythm (SR) spontaneously. The aim of the study was to assess if AFR can predict spontaneous conversion in patients with recent-onset AF.
  
  
  RESULTS
  Files of consecutive patients with AF < 48 h seeking emergency room care during a 12-month period were screened (n = 225). Patients with thyroid illness, acute ischaemic heart disease (IHD) or acute congestive heart failure, significant valvular heart disease, congenital heart disease, history of cardiac surgery or catheter ablation, or on class I/III antiarrhythmics were excluded. Atrial fibrillatory rate was obtained by QRST cancellation and time frequency analysis of electrocardiogram at admission. The study population comprised 148 patients (age 64 ± 13 years, 52 men), of whom 48 converted to SR within 18 h. Those converting spontaneously comprised more women, had a higher prevalence of first-ever AF episode, IHD, and a lower AFR. The multivariate analysis revealed: AFR < 350 fibrillations per minute [odds ratio (OR) 3.7, 95% confidence interval (CI) 1.3-10.5, P = 0.016], IHD (OR 5.7, 95% CI 1.5-22.4, P = 0.012) and first-ever AF episode (OR 4.1, 95% CI 1.3-13.0, P = 0.015) as independent predictors of spontaneous conversion.
  
  
  CONCLUSIONS
  A low AFR was predictive of spontaneous conversion in patients with recent-onset AF. Along with first-ever AF episode and IHD, AFR can be used in assessing likelihood of spontaneous conversion, if proven in prospective studies.
authors.affiliation: Department of Cardiology, Center for Integrative Electrocardiology at Lund University (CIEL), Lund, Sweden.
authors.forename: Mariam B
authors.initials: MB
authors.lastname: Choudhary
authors.forename: Fredrik
authors.initials: F
authors.lastname: Holmqvist
authors.forename: Jonas
authors.initials: J
authors.lastname: Carlson
authors.forename: Hans-Jörgen
authors.initials: HJ
authors.lastname: Nilsson
authors.forename: Anders
authors.initials: A
authors.lastname: Roijer
authors.forename: Pyotr G
authors.initials: PG
authors.lastname: Platonov
mesh_terms: D000368:Aged; D001281:Atrial Fibrillation / Q000175:diagnosis / Q000453:epidemiology / Q000503:physiopathology*; D004562:Electrocardiography; D005260:Female; D006329:Heart Conduction System / Q000503:physiopathology*; D006801:Humans; D053208:Kaplan-Meier Estimate; D008297:Male; D008875:Middle Aged; D015999:Multivariate Analysis; D016017:Odds Ratio; D015995:Prevalence; D011379:Prognosis; D012042:Registries; D012075:Remission, Spontaneous; D012189:Retrospective Studies; D012307:Risk Factors; D013548:Sweden / Q000453:epidemiology; D013997:Time Factors
keywords: Atrial fibrillation; Atrial fibrillatory rate; First-ever atrial fibrillation episode; Ischaemic heart disease; Recent-onset atrial fibrillation; Spontaneous conversion; Time frequency analysis