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Evolution of left ventricular ejection fraction after acute myocardial infarction: implications for implantable

Johanna Sjöblom1, Josephine Muhrbeck2, Nils Witt2

  • 1From 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.

Circulation
|July 31, 2014
PubMed

Insights

Most patients with reduced ejection fraction after acute myocardial infarction (AMI) show significant left ventricular (LV) function improvement by one month. This suggests delaying implantable cardioverter-defibrillator (ICD) implantation may not be necessary for these patients.

Area of Science:

  • Cardiology
  • Cardiac Electrophysiology

Background:

  • Implantable cardioverter-defibrillator (ICD) therapy is vital for survival in acute myocardial infarction (AMI) patients with reduced left ventricular ejection fraction (LVEF).
  • Optimal timing for ICD implantation post-AMI remains undetermined, despite the highest risk of sudden cardiac death occurring within the first month.

Purpose of the Study:

  • To determine the proportion of post-AMI patients with sufficient left ventricular (LV) function recovery to potentially obviate the need for an ICD.
  • To assess the time course of LV function improvement after AMI.

Main Methods:

  • Prospective study including 100 patients admitted for AMI with LVEF ≤40%.
  • Echocardiographic assessments of LVEF were performed at 5 days, 1 month, and 3 months post-AMI.
  • Monitoring for life-threatening arrhythmias during the first 9 weeks.

Main Results:

  • Initial LVEF was 31±5.8%.
  • By 1 month post-AMI, 55% of patients achieved an LVEF >35%, with most significant improvement noted by this time point.
  • Further LVEF improvement between 1 and 3 months was minimal (mean difference 1.9 percentage units).
  • 10% of patients experienced life-threatening arrhythmias within the first 9 weeks.

Conclusions:

  • Significant LVEF recovery is common in post-AMI patients, often evident by the 1-month follow-up.
  • Delaying ICD implantation beyond 1 month may not be warranted for many patients due to established functional recovery.
  • The 10% incidence of serious arrhythmias highlights the persistent risk of sudden cardiac death in this patient cohort.
Abstract

Keywords:
defibrillators, implantableechocardiographyheart failuremyocardial infarctionrisk assessment

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