Evolution of Left Ventricular Ejection Fraction After Acute Myocardial Infarction: Implications for Implantable Defibrillator Eligibility
Background—ICD therapy improves survival in patients with reduced left ventricular ejection fraction (LVEF) after acute myocardial infarction (AMI). Although the risk of sudden cardiac death (SCD) is highest in the first month after AMI, there is no survival benefit of early ICD implantation and the optimal time frame has yet to be established. The aim of this study was to investigate what proportion of post-AMI patients improved their LV function to such extent that the indication for ICD was no longer present.
Methods and Results—Patients admitted for AMI with reduced LVEF (≤40%) were eligible for inclusion. Repeat echocardiographic examinations were performed five days, one and three months after the AMI. We prospectively included 100 patients with LVEF 31±5.8% after AMI. At one month follow-up, 55% had an LVEF >35%. The main improvement in LVEF had occurred by one month. The mean difference in LVEF over the next two months was small, 1.9 percentage units. During the first nine weeks 10% of the patients suffered from life-threatening arrhythmias.
Conclusions—Most patients improve their LVEF after AMI and in the majority the improvement could be confirmed after one month, implying that further delay of ICD implantation may not be warranted. Life-threatening arrhythmias occurred in 10% of the patients illustrating the high risk for SCD in this population.
- implanted cardioverter defibrillator
- acute myocardial infarction
- left ventricular ejection fraction
- sudden cardiac death, arrhythmia
- Received March 9, 2014.
- Revision received June 10, 2014.
- Accepted June 16, 2014.