The relationship between left ventricular ejection fraction and infarct size assessed by MRI

Abstract

Objectives: We sought to study the relationship between left ventricular ejection fraction (LVEF) and infarct size in patients with ischemic heart disease (IHD) using magnetic resonance imaging (MRI), and to determine a dysfunction index based on the maximum possible LVEF in relation to infarct size.

Design: In 149 patients with chronic IHD, LVEF and infarct size were quantified by MRI. Dysfunction index was defined as the maximum possible LVEF minus measured LVEF.

Results: The maximum possible LVEF was found to be LVEF=72.2-[1.18*infarct size]. Dysfunction index for the study population was mean 20 (range -6 to 57), 74% of the study population had a dysfunction index >10 and 44% had a dysfunction index >20.

Conclusions: The present study suggests that infarct size by MRI can be used to estimate a maximum possible LVEF and a dysfunction index. The distribution of dysfunction index in the population suggests a considerable prevalence of dysfunctional but viable myocardium. Future studies are needed to assess if the dysfunction index can be useful to assess the potential for improvement in LVEF following revascularization.