Implantable Cardioverter-Defibrillator Use Among Medicare Patients With Low Ejection Fraction After Acute Myocardial Infarction.

IMPORTANCE Implantable cardioverter-defibrillators (ICDs) are not recommended within 40 days of myocardial infarction (MI); thus, ICD implantation might not be considered during the post-MI care transition. OBJECTIVE To examine ICD implantation rates and associated mortality among older MI patients with low ejection fraction (EF). DESIGN, SETTING, AND PARTICIPANTS Retrospective observational study of Medicare beneficiaries with an EF of 35% or less after MI, treated at 441 US hospitals between 2007 and 2010, excluding patients with prior ICD implantation. Follow-up data were available through December 2010. EXPOSURES ICD implantation within 1 year of MI vs no ICD implantation within 1 year of MI. MAIN OUTCOMES AND MEASURES Patient characteristics associated with receiving an ICD within 1 year after discharge and 2-year mortality associated with ICD implantation. RESULTS Among 10,318 MI patients with EF of 35%or lower, the cumulative 1-year ICD implantation rate was 8.1% (95%CI, 7.6%-8.7%). Patients with ICD implantation were more likely to have prior coronary artery bypass graft procedures, higher peak troponin levels, in-hospital cardiogenic shock, and cardiology follow-up within 2 weeks after discharge relative to patients who did not receive an ICD within 1 year. Implantation of ICD was associated with lower 2-year mortality (15.3 events per 100 patient-years [128 deaths in 838 patient-years] vs 26.4 events per 100 patient-years [3033 deaths in 11 479 patient-years]; adjusted HR, 0.64; 95%CI, 0.53-0.78). [table: see text] CONCLUSIONS AND RELEVANCE In this large registry study of older patients who experienced MI from 2007-2010, fewer than 1 in 10 eligible patients with low EF received an ICD within 1 year after MI, although ICD implantation was associated with lower risk-adjusted mortality at 2 years. Additional research is needed to determine evidence-based approaches to increase ICD implantation among eligible patients.