Change in myocardial function after resuscitated sudden cardiac arrest and its impact on long-term mortality and defibrillator implantation

The impact of left ventricular ejection fraction (LVEF) changes after sudden cardiac arrest (SCA) on implantable defibrillator (ICD) utilization and long-term survival is not known. We therefore evaluated the influence of LVEF on these parameters in SCA survivors.

Data were collected on consecutive SCA survivors who had ≥1 echocardiogram after SCA and who survived to hospital discharge (n = 655). The median time from baseline to first follow-up echocardiogram was 162 days. LVEF ≥50% was defined as normal. Patients were classified into 4 groups according to baseline (LVEFb) and follow-up (LVEFf) myocardial function: normal LVEFb and LVEFf (group1, n = 261); reduced LVEFb and normal LVEFf (group 2, n = 104); normal LVEFb but reduced LVEFf (group 3, n = 41); and reduced LVEFb and LVEFf (group 4, n = 249). All-cause mortality and time to ICD implantation were examined in all groups.

Over a median follow up of 4.3 years, death occurred in 279 (42%) of patients. Compared with patients in group 1, patients with any reduced LVEF at any time (groups 2-4) had significantly higher mortality, even after adjusting for unbalanced covariates (HR = 1.44, 95.0% CI 1.05-1.95, p = 0.022). ICDs were most commonly implanted in patients with persistently reduced LVEF (group 4: HR = 1.72, 95% CI = 1.26-2.35, p = 0.001).

We demonstrate that, in survivors of SCA, a reduced LVEF at or after the index event is associated with higher mortality but that patients with persistently reduced LVEF were most likely to receive ICD therapy. These findings have implications on the management of SCA survivors.