Outcomes and Left Ventricular Ejection Fraction in Cardiac Magnetic Resonance: Challenging the “Higher Is Better”

Abstract

BACKGROUND: Contradictory evidence exists regarding the correlation between supranormal left ventricular ejection fraction (LVEF) and adverse outcomes. This study aimed to elucidate the prognostic value of supranormal LVEF. METHODS: This retrospective cohort study analyzed patients referred for cardiac magnetic resonance imaging to assess myocardial ischemia or viability. Subjects were stratified into eig8ht LVEF groups: <20%, 20% to 30%, 30% to 40%, 40% to 50%, 50% to 60%, 60% to 70%, 70% to 80%, and ≥80%. Primary outcomes included cardiovascular death, heart failure, myocardial infarction, and stroke. The extracellular volume fraction was measured. RESULTS: The study cohort comprised 3279 patients (mean age 68.0±12.7 years; 64.0% female). The group with 60% to 70% LVEF had the lowest risk and was used as the reference group. The median follow-up was 41.4 months (interquartile range, 33.9–49.7 months). The group with LVEF <20% exhibited the highest composite outcome risk (unadjusted hazard ratio [HR], 6.77 [95% CI, 3.81–12.03]; P<0.001; adjusted HR, 2.68 [95% CI, 1.28–5.62]; P<0.001). The groups with LVEF 70% to 80% and ≥80% showed increased risk (adjusted HR, 1.96 [95% CI, 1.23–3.08]; P=0.004; 2.16 [95% CI, 1.33–3.52]; P=0.002, respectively). A greater extracellular volume fraction was associated with an LVEF of 70% to 80% and ≥80% (adjusted odds ratios, 1.34 [95% CI, 1.03–1.74]; P=0.027; and 1.74 [95% CI, 1.30–2.34]; P<0.001, respectively). CONCLUSIONS: LVEF >70% demonstrated increased event rates compared with an LVEF of 60% to 70%. The supranormal LVEF warrants further investigation into its pathogenesis and management.