title: Impact of congestive heart failure and left ventricular systolic function on the prognostic significance of atrial fibrillation and atrial flutter following acute myocardial infarction.
abstract: BACKGROUND
  Reports on the prognostic importance of atrial fibrillation following myocardial infarction have provided considerable variation in results. Thus, this study examined the impact of left ventricular systolic function and congestive heart failure on the prognostic importance of atrial fibrillation in acute myocardial infarction patients that might explain previous discrepancies.
  
  
  METHODS
  The study population was 6676 patients consecutively admitted to hospital with acute myocardial infarction. Information on the presence of atrial fibrillation/flutter, left ventricular systolic function and congestive heart failure were prospectively collected. Mortality was followed for 5 years.
  
  
  RESULTS
  In patients with left ventricular ejection fraction<0.25, atrial fibrillation/atrial flutter was associated with an increased in-hospital mortality (OR=1.8 (1.1-3.2); p<0.05) but not an increased 30-day mortality. In patients with 0.25<or=left ventricular ejection fraction<or=0.35, atrial fibrillation/atrial flutter was associated with an increased in-hospital mortality (OR=1.7 (1.3-2.3); p<0.001) and an increased 30-day mortality (OR=1.7 (1.3-2.2); p<0.001). In-hospital and 30-day mortality was not increased in patients with left ventricular ejection fraction>0.35. In patients with congestive heart failure, atrial fibrillation/atrial flutter was associated with an increased in-hospital mortality (OR=1.5 (1.2-1.9); p<0.001) and increased 30-day mortality (OR=1.4 (1.1-1.7); p<0.001) but not in patients without congestive heart failure. In hospital survivors, atrial fibrillation/atrial flutter was associated with an increased long-term mortality in all subgroups except those with left ventricular ejection fraction<0.25.
  
  
  CONCLUSIONS
  Atrial fibrillation/atrial flutter is primarily associated with increased in-hospital mortality in heart failure patients. Long-term mortality is increased in all subgroups except those with left ventricular ejection fraction<25%.
authors.affiliation: Department of Cardiology Y, Bispebjerg University Hospital, Bispebjerg Bakke 23, 2400 København NV, Denmark. odplc@mail.dk
authors.forename: Ole Dyg
authors.initials: OD
authors.lastname: Pedersen
authors.forename: Henning
authors.initials: H
authors.lastname: Bagger
authors.forename: Lars
authors.initials: L
authors.lastname: Køber
authors.forename: Christian
authors.initials: C
authors.lastname: Torp-Pedersen
mesh_terms: D000368:Aged; D001281:Atrial Fibrillation / Q000453:epidemiology / Q000401:mortality* / Q000503:physiopathology; D001282:Atrial Flutter / Q000453:epidemiology / Q000401:mortality* / Q000503:physiopathology; D015897:Comorbidity; D005260:Female; D006333:Heart Failure; D017052:Hospital Mortality; D006801:Humans; D008297:Male; D009203:Myocardial Infarction / Q000453:epidemiology* / Q000503:physiopathology; D011379:Prognosis; D016277:Ventricular Function, Left