title: New-onset atrial fibrillation predicts malignant arrhythmias in post-myocardial infarction patients--a Cardiac Arrhythmias and RIsk Stratification after acute Myocardial infarction (CARISMA) substudy.
abstract: BACKGROUND
  After myocardial infarction (MI) the risk of sudden cardiac death due to arrhythmias is substantial.
  
  
  OBJECTIVE
  The purpose of this study was to investigate if new-onset atrial fibrillation (AF) is associated with development of potential malignant brady- and tachyarrhythmias after an acute MI.
  
  
  METHODS
  The study included 277 post-MI patients from the CARISMA study with left ventricular ejection fraction ≤ 40%, New York Heart Association class I, II, or III and no history of AF. All patients were implanted with an implantable cardiac monitor within 4 to 27 days after an acute MI and followed every 3 months for 2 years. Time-dependent association between new-onset AF > 30 s and the development of bradyarrhythmias and/or ventricular tachyarrhythmias were investigated using Cox proportional hazard regressions.
  
  
  RESULTS
  New-onset AF was associated with an increased risk of bradyarrhythmias when adjusting for male gender and baseline age, left ventricular ejection fraction and QRS width (HR = 2.8 [1.3-5.8], P = .006). Similarly, new-onset AF predicted ventricular tachyarrhythmias when adjusting for New York Heart Association class ≥ II and baseline QRS width (HR = 2.3 [1.2-4.4], P = .019). After dividing ventricular tachyarrhythmias into subgroups of non-sustained ventricular tachycardia (VT), sustained VT and ventricular fibrillation (VF), new-onset AF was significantly associated with an increased risk of non-sustained- and sustained VT but not VF (non-sustained VT: HR = 3.5 [1.7-7.2], P < .001, sustained VT: HR = 4.2 [1.1-15.7], P = .035, VF: HR = 1.1 [0.2-5.8], P = .877).
  
  
  CONCLUSIONS
  In patients surviving a MI with reduced left ventricular systolic function, new-onset AF is associated with a significantly increased risk of developing ventricular brady- and tachyarrhythmias.
authors.affiliation: Department of Cardiology, Gentofte University Hospital, Copenhagen, Denmark; University of Rochester Medical Center, Heart Research Follow-Up Program, Rochester, NY. Electronic address: annechristinehuth@hotmail.com.
authors.forename: Anne-Christine Huth
authors.initials: AC
authors.lastname: Ruwald
authors.forename: Poul Erik
authors.initials: PE
authors.lastname: Bloch Thomsen
authors.forename: Uffe
authors.initials: U
authors.lastname: Gang
authors.forename: Rikke Mørch
authors.initials: RM
authors.lastname: Jørgensen
authors.forename: Heikki V
authors.initials: HV
authors.lastname: Huikuri
authors.forename: Christian
authors.initials: C
authors.lastname: Jons
mesh_terms: D000368:Aged; D001145:Arrhythmias, Cardiac / Q000150:complications* / Q000453:epidemiology; D001281:Atrial Fibrillation / Q000150:complications*; D015716:Electrocardiography, Ambulatory / Q000379:methods*; D005260:Female; D006801:Humans; D015994:Incidence; D008297:Male; D008875:Middle Aged; D009203:Myocardial Infarction / Q000150:complications* / Q000503:physiopathology; D016016:Proportional Hazards Models; D018570:Risk Assessment; D012307:Risk Factors; D016277:Ventricular Function, Left