In patients who have experienced myocardial infarction (MI), a moderately reduced level (≤ 35%) of left-ventricular ejection fraction (LVEF) is indicated as the threshold at which cardiologists should consider an implantable cardioverter-defibrillator (ICD), to reduce the likelihood of sudden cardiac death (SCD). Nonetheless, recent studies have indicated that patients with inducible arrhythmia and LVEF > 35% can also benefit from ICD placement. Thus, as the majority of out-of-hospital SCD patients present with LVEF of ≥40%, many questions surround the criteria for ICD placement based on a revised LVEF threshold and the presence of other risk factors.
In the multicenter, prospective, observational-cohort PRESERVE EF study, researchers investigated outcomes in 575 post-MI patients with LVEF ≥ 40%. They sought to determine whether risk stratification based on the presence of non-invasive risk factors (NIRFs) and inducible arrythmia could identify patients with relatively well-preserved LVEF (i.e. ≥ 40% ), that might benefit from ICD placement.
Of the 575 patients, 41 were considered as being at high risk for a major arrhythmic event (MAE) based on the presence of ≥ 1 NIRF and arrythmia inducible, according to programed ventricular stimulation (PVS); 37 of these patients (90 %) were fitted with an ICD (4 declined). Mean follow-up was 32 months, during which 9 of the 37 ICD devices were activated, indicative of a 22 % prevalence of MAE (equivalent to an annual incidence rate of 8.2%).
The data suggests that in a population of post-MI patients with LVEF ≥ 40 %, ≥ 1 NIRF, and inducible arrythmia, ICD placement could reduce the risk of SCD-related mortality associated with MAEs.
Author: Daniel Guns, Cardiology Update
Original article: Eur Heart J. 2019;0:1-10
