Implantable cardioverter-defibrillator placement among patients with left ventricular ejection fraction ≤35 % at least 40 days after acute myocardial infarction

Background:Implantable cardioverter-defibrillators (ICDs) reduce the risk of sudden cardiac death among patients with persistently reduced (≤35 %) left ventricular ejection fraction (LVEF) at least 40 days following acute myocardial infarction (AMI). Few prior studies have used LVEF measured after the 40-day waiting period to examine primary prevention ICD placement. Methods:We sought to determine factors associated with ICD placement among patients who met LVEF criteria post-MI within a large integrated health care system in the U.S by conducting a retrospective cohort study of Veteran patients hospitalized for AMI from 2004 to 2017 who had documented LVEF ≤35 % from echocardiograms performed between 40 and 455 (90 days +1 year) days post-MI. We used multivariable logistic regression to examine factors associated with ICD placement. Results:Of 12,893 patients with LVEF ≤35 % at least 40 days post-MI, 2176 (16.9 %) received an ICD between 91- and 455-days post-MI. Younger age, fewer comorbidities, revascularization with PCI, and greater use of GDMT were associated with increased odds of receiving an ICD. However, half of patients treated with a beta-blocker, ACE inhibitor or angiotensin receptor blocker, and mineralocorticoid receptor antagonist prior to LVEF assessment did not receive an ICD. Eligible Black patients were less likely (odds ratio 0.80, 95 % confidence interval 0.69-0.92) to receive an ICD than White patients. Conclusion:Many factors affect ICD placement among Veteran patients with a confirmed LVEF ≤35 % at least 40 days post-MI. Greater understanding of factors influencing ICD placement would help clinicians ensure guideline-concordant care.