Evaluation of Left Ventricular Global and Regional Myocardial Work Quantitatively by Pressure-strain Loop in Young Strength Athletes With Different Heart Rates

Abstract

Objective: The present study aimed to investigate the difference in left ventricular (LV) global and regional myocardial work (MW) of strength athletes with different heart rates (HR) through non-invasive LV pressure-strain loop (PSL) and further address the effect of athlete’s resting heart rate variability on the LV systolic function.Methods:Fifty young professional wrestlers were collected randomly and divided into two groups in accordance with their different heart rates: the low HR group (45~60 bpm, n1=25) and the high HR group (60~80 bpm, n2=25). Thirty individuals with gender- and age-matched healthy volunteers served as controls (n3=30). Global and regional MW parameters were evaluated using LV-PSL derived from speckle tracking echocardiography (STE) and brachial artery pressure. The differences between three groups of data and the linear relationship among conventional echocardiographic parameters and global myocardial work efficiency (GWE) were analyzed.Results:The indicators of global and regional MW did statistically significantly differ between the athlete and control groups. Compared with the control group, Peak strain dispersion (PSD) and global myocardial wasted work (GWW) increased while GWE reduced all in the low HR and high HR groups, and global myocardial work index (GWI), global myocardial constructive work (GCW), global longitudinal strain (GLS) decreased in the low HR group (all P＜0.05). In comparison to the low HR group, GWI, GCW, GWW, PSD increased in the high HR group and GWE reduced (P＜0.05). According to the regional MW analysis, the mean regional myocardial work index (RMWI) was increased gradually from basal to apical levels, which were similar across the three groups, but regional myocardial work efficiency (RMWE) did not. Multiple linear regression analysis indicated that the HR, posterior wall thickness (PWT), interventricular septal thickness (IVST), GLS, and PSD were well correlated with GWE (b’= -0.247, -0.390, -0.370, 0.340, and -0.554, respectively, P＜0.05).Conclusions:The sub-clinical changes of LV contractile performance were more obvious in young strength athletes with high resting heart rates and PSL could be used to assess LV GMW and RMW quantitatively and accurately in reflecting LV systolic function.