Temporal trends in left ventricular ejection fraction before sudden death in patients with heart failure

Abstract

Background: Risk stratification for sudden cardiac death (SCD) in heart failure (HF) patients is largely based on left ventricular ejection fraction (LVEF) of ≤35%. However, disease-related LV remodeling and medical treatment may change LVEF over time.

Objective: This study aimed to evaluate the temporal trends in LVEF in patients with HF who experience an SCD.

Methods: We performed 2 retrospective cohort studies (discovery and validation) of patients who experienced SCD after an established diagnosis of HF. Individuals were identified from 2 separate population-based studies of SCD in Oregon and California, if they underwent ≥2 echocardiographic evaluations performed at least 6 months apart.

Results: The Oregon discovery cohort included 526 patients (male 63.9%; age 70.4 [13.2]), and the California validation cohort 191 patients (male 60.7%; age 74.6 [13.6]). In the discovery cohort, 45% of patients with LVEF of ≤35% on first assessment were reclassified to LVEF of >35% at final assessment (P < .001). Among patients with LVEF of 36%-49%, 66% were reclassified to either ≤35% or >50% (P < .001). In patients with LVEF of >50%, 32% were reclassified to LVEF of <50% (P < .001). Overall, 41.1% of patients in the discovery cohort were reclassified based on LVEF (P < .001). No distinguishing characteristics were identified between patients with an initial LVEF of ≤35% who improved or did not. Similar findings were observed in the validation cohort.

Conclusion: LVEF category changed significantly over time, resulting in substantial reclassification of risk before the SCD event. These findings highlight the major limitation of using LVEF measured at a single time point as the main predictor of SCD risk.

Keywords: Echocardiography; Heart failure; Left ventricular ejection fraction; Sudden cardiac death; Temporal trends.