Global Left Ventricular Myocardial Work Efficiency in Healthy Individuals and Patients with Cardiovascular Disease

Abstract

Global left ventricular (LV) myocardial work efficiency, the ratio of constructive to wasted work in all LV segments, reflects the efficiency by which mechanical energy is expended during the cardiac cycle. Global LV myocardial work efficiency can be derived from LV pressure-strain loop analysis incorporating both noninvasively estimated blood pressure recordings and echocardiographic strain data. The aim of this study was to characterize global LV myocardial work efficiency in healthy individuals and patients with cardiovascular (CV) risk factors or overt cardiac disease. We retrospectively included healthy individuals without structural heart disease or CV risk factors, who were selected from an ongoing database of normal individuals, and matched for age and sex with (1) individuals without structural heart disease but with CV risk factors, (2) postinfarct patients without heart failure, and (3) heartfailure patients with reduced ejection fraction (HFrEF). Global LV myocardial work efficiency was estimated with a proprietary algorithm from speckle-tracking strain analyses, as well as noninvasive blood pressure measurements. In total, 120 individuals (44% male, 53±13years) were included (n=30 per group). In healthy individuals without structural heart disease or CV risk factors, global LV myocardial work efficiency was 96.0% (interquartile range, 95.0%-96.3%). Myocardial efficiency of the LV did not differ significantly between individuals without structural heart disease and those with CV risk factors (96.0% vs 96.0%; P=.589). Global LV myocardial work efficiency, however, was significantly decreased in postinfarct patients (96.0% vs 93.0%, P<.001) and in those with HFrEF (96.0% vs 69.0%; P<.001). While global LV myocardial work efficiency was similar in normal individuals and in those with CV risk factors, it was decreased in postinfarct and HFrEF patients. The global LV myocardial work efficiency values presented here show distinct patterns in different cardiac pathologies.