title: Relationship of functional mitral regurgitation to new-onset atrial fibrillation in acute myocardial infarction.
abstract: OBJECTIVE
  The role of factors that increase left atrial pressure or cause acute left atrial dilatation is frequently emphasised in the pathogenesis of atrial fibrillation (AF) in patients with acute myocardial infarction (AMI). This study was designed to test the hypothesis that functional mitral regurgitation (FMR) occurring after AMI may promote AF by producing left atrial volume overload.
  
  
  METHODS
  Intensive care unit of a tertiary care hospital.
  
  
  METHODS
  1920 patients admitted with AMI were studied. Patients with known AF were excluded. FMR was classified using echocardiography into three groups: none; mild FMR and moderate or severe FMR. The relationship between FMR and AF occurring at any time during the hospital course was examined using multivariable logistic regression.
  
  
  RESULTS
  Mild FMR was present in 744 patients (38.8%) and moderate or severe FMR was present in 150 patients (7.8%). AF developed in 51 (5.0%), 83 (11.2%) and 28 (18.7%) patients with no FMR, mild FMR and moderate or severe FMR, respectively (p trend <0.001). In multivariable logistic regression, both mild (odds ratio (OR) 1.6; 95% CI 1.1 to 2.3, p=0.02) and moderate or severe FMR (OR 2.1; 95% CI 1.2 to 3.6, p=0.007) were independent predictors of AF. There was a significant interaction between the left ventricular ejection fraction and FMR (p=0.003) such that mild FMR was predictive of AF only in patients with a reduced (<45%) ejection fraction.
  
  
  CONCLUSIONS
  There is a graded independent association between the severity of FMR and the new onset of AF in patients with AMI.
authors.affiliation: Department of Cardiology, Rambam Medical Center, Bat Galim, POB 9602, Haifa 31096, Israel.
authors.forename: Fadel
authors.initials: F
authors.lastname: Bahouth
authors.forename: Diab
authors.initials: D
authors.lastname: Mutlak
authors.forename: Moran
authors.initials: M
authors.lastname: Furman
authors.forename: Anees
authors.initials: A
authors.lastname: Musallam
authors.forename: Haim
authors.initials: H
authors.lastname: Hammerman
authors.forename: Jonathan
authors.initials: J
authors.lastname: Lessick
authors.forename: Saleem
authors.initials: S
authors.lastname: Dabbah
authors.forename: Shimon
authors.initials: S
authors.lastname: Reisner
authors.forename: Yoram
authors.initials: Y
authors.lastname: Agmon
authors.forename: Doron
authors.initials: D
authors.lastname: Aronson
mesh_terms: D001281:Atrial Fibrillation / Q000209:etiology* / Q000401:mortality; D005260:Female; D006333:Heart Failure / Q000209:etiology; D006801:Humans; D053208:Kaplan-Meier Estimate; D008297:Male; D008875:Middle Aged; D008944:Mitral Valve Insufficiency / Q000150:complications* / Q000401:mortality; D009203:Myocardial Infarction / Q000150:complications* / Q000401:mortality; D011446:Prospective Studies; D012307:Risk Factors; D016896:Treatment Outcome