Baron T, et al. - This study was performed on consecutive patients with myocardial infarction (MI) and initially normal or impaired left ventricular (LV) ejection fraction (EF), in order to determine the changes of global longitudinal strain (GLS) and their predictors in relation to classical echocardiographic parameters of LV function, over 1 year. Although the divergent evolution of GLS compared with EF and ventricular volumes was evident but in patients with initially both normal and impaired EF, a significant improvement in GLS was noted one-year post-MI. Independent predictors of GLS improvement included initial impairment of LV function [by EF, wall motion score index (WMSI), or GLS], male gender, non-smoking, and treatment with beta-blockers. Furthermore, even in patients with normal EF at baseline and during follow-up, the presence of LV remodelling was observed; this confirmed limited functional assessment by EF alone.

Methods

• Echocardiography was performed within 72 h from admission and after 1 year in a total of 285 patients with MI prospectively included in the REBUS (RElevance of Biomarkers for future risk of thromb-oembolic events in UnSelected post-myocardial infarction patients) study.

Results

• A a normal EF was reported at baseline in 213 (74.7%) of MI patients, but an impaired GLS (≥-18.0%) was observed in 70.4% of them.
• During 1-year follow-up, the following changes were noted in patients with normal EF at baseline: GLS improved from -15.8% to -17.4% (10.1% relative change); EF decreased from 62.5% to 59.9% (4.0% relative change); indexed end-diastolic volume, indexed end-systolic volume, and indexed stroke volume increased with 15.6%, 24.8%, and 10.0% of relative change, respectively (P < 0.001 for all the comparisons).
• In the whole cohort, independent predictors of GLS improvement included initial impairment of LV function [by EF, wall motion score index (WMSI), or GLS], male gender, non-smoking, and treatment with beta-blockers.
• Findings demonstrated that over 1 year, GLS improved from -11.9% to -14.8% (24.4% relative change) and EF from 44.6% to 52.6% (18.2% relative change) (P < 0.001 for both) in the group with initially impaired EF.
• A significant correlation of improvement in GLS with EF increase was evident in the group with impaired EF (r = -0.41, P=0.001) but not in the patients with normal EF (r = -0.14, P=ns).