title: Evolution of left ventricular ejection fraction after acute myocardial infarction: implications for implantable cardioverter-defibrillator eligibility.
abstract: BACKGROUND
  Implantable cardioverter-defibrillator therapy improves survival in patients with reduced left ventricular ejection fraction (LVEF) after acute myocardial infarction (AMI). Although the risk of sudden cardiac death is highest in the first month after AMI, there is no survival benefit of early implantable cardioverter-defibrillator implantation, and the optimal time frame has yet to be established. Thus, the aim of this study was to investigate what proportion of post-AMI patients had improved LV function to such an extent that the indication for implantable cardioverter-defibrillator was no longer present.
  
  
  RESULTS
  Patients admitted for AMI with reduced LVEF (≤40%) were eligible for inclusion. Repeat echocardiographic examinations were performed 5 days, 1 month, and 3 months after the AMI. We prospectively included 100 patients with LVEF of 31±5.8% after AMI. At the 1-month follow-up, 55% had an LVEF >35%. The main improvement in LVEF had occurred by 1 month. The mean difference in LVEF over the next 2 months was small, 1.9 percentage units. During the first 9 weeks, 10% of the patients suffered from life-threatening arrhythmias.
  
  
  CONCLUSIONS
  Most patients have improved LVEF after AMI, and in the majority, the improvement can be confirmed after 1 month, implying that further delay of implantable cardioverter-defibrillator implantation may not be warranted. Life-threatening arrhythmias occurred in 10% of the patients, illustrating the high risk for sudden cardiac death in this population.
authors: From the Karolinska Institutet, Department of Clinical Sciences, Division of Cardiovascular Medicine, Danderyd University Hospital, Stockholm, Sweden (J.S., J.M., M.A., V.F.K.); and Karolinska Institutet, Department of Clinical Science and Education, Division of Cardiology, Södersjukhuset, Stockholm, Sweden (N.W.). johanna.sjoblom@ds.se.
authors: Johanna
authors: J
authors: Sjöblom
authors: From the Karolinska Institutet, Department of Clinical Sciences, Division of Cardiovascular Medicine, Danderyd University Hospital, Stockholm, Sweden (J.S., J.M., M.A., V.F.K.); and Karolinska Institutet, Department of Clinical Science and Education, Division of Cardiology, Södersjukhuset, Stockholm, Sweden (N.W.).
authors: Josephine
authors: J
authors: Muhrbeck
authors: From the Karolinska Institutet, Department of Clinical Sciences, Division of Cardiovascular Medicine, Danderyd University Hospital, Stockholm, Sweden (J.S., J.M., M.A., V.F.K.); and Karolinska Institutet, Department of Clinical Science and Education, Division of Cardiology, Södersjukhuset, Stockholm, Sweden (N.W.).
authors: Nils
authors: N
authors: Witt
authors: From the Karolinska Institutet, Department of Clinical Sciences, Division of Cardiovascular Medicine, Danderyd University Hospital, Stockholm, Sweden (J.S., J.M., M.A., V.F.K.); and Karolinska Institutet, Department of Clinical Science and Education, Division of Cardiology, Södersjukhuset, Stockholm, Sweden (N.W.).
authors: Mahbubul
authors: M
authors: Alam
authors: From the Karolinska Institutet, Department of Clinical Sciences, Division of Cardiovascular Medicine, Danderyd University Hospital, Stockholm, Sweden (J.S., J.M., M.A., V.F.K.); and Karolinska Institutet, Department of Clinical Science and Education, Division of Cardiology, Södersjukhuset, Stockholm, Sweden (N.W.).
authors: Viveka
authors: V
authors: Frykman-Kull
mesh_terms: D000368:Aged; D001145:Arrhythmias, Cardiac / Q000628:therapy; D017147:Defibrillators, Implantable; D004452:Echocardiography; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009203:Myocardial Infarction / Q000150:complications / Q000000981:diagnostic imaging / Q000503:physiopathology*; D013318:Stroke Volume; D016277:Ventricular Function, Left
keywords: defibrillators, implantable; echocardiography; heart failure; myocardial infarction; risk assessment