Influence of left ventricular hypertrophy on infarct size and left ventricular ejection fraction in ST-elevation myocardial infarction.

Background: Left ventricular hypertrophy (LVH) predisposes to larger infarct size, which may be underestimated by the left ventricular ejection fraction (LVEF) due to supranormal systolic performance often present in patients with LVH. The aim of the study was to compare infarct size and LVEF in patients with ST-segment elevation myocardial infarction (STEMI) and increased left ventricular mass on cardiac magnetic resonance (CMR).
Methods: The study included unselected group of 52 patients (61±11 years, 69% male) with first STEMI who had CMR after median 5 days from the onset of the event. Left ventricular hypertrophy (LVH) was defined as left ventricular mass index exceeding 95th percentile of references values for age and gender. Infarct size was assessed with means of late gadolinium enhancement (LGE).
Results: LVH was found in 16 patients (31%). In comparison to the rest of the group, patients with LVH had higher absolute and relative infarct mass (p=0.002 and p=0.02, respectively). LVH was related to higher prevalence of microvascular obstruction and myocardial haemorrhage and higher number of LV segments with transmural necrosis (p=0.02, p=0.01 and p=0.01, respectively). Despite marked difference in the infarct size between both studied subgroups there was no difference in LVEF and mean number of dysfunctional LV segments.
Conclusions: Patients with LVH undergoing STEMI have larger infarct size underestimated by the LV systolic performance in comparison to patients without LVH.
(Copyright © 2011 Elsevier Ireland Ltd. All rights reserved.)