Interrelationships between Peak Strain Dispersion, Myocardial Work Indices, Isovolumetric Relaxation and Systolic–Diastolic Coupling in Middle-Aged Healthy Subjects

In echocardiography, peak strain dispersion (PSD) is the standard deviation of the time to peak longitudinal strain for each left ventricular (LV) segment during systole. It assesses the coordination and synchrony of LV segment contractility. Global work efficiency (GWE) and global wasted work (GWW) quantify LV myocardial work and, if impaired, the coupling between LV systolic contraction and early relaxation. Isovolumetric relaxation (IVRT) measures the duration of initial LV relaxation, while the ratio of early diastolic recoil to systolic excursion (E′(VTI)/S′(VTI)) describes systolic–diastolic coupling. We evaluated these parameters in 69 healthy subjects and found that PSD correlated negatively with GWE (r = −0.49, p < 0.0001) and E′(VTI)/S′(VTI) (r = −0.44, p = 0.0002), but positively with GWW (r = 0.4, p = 0.0007) and IVRT (r = 0.53, p < 0.0001). GWE correlated negatively with GWW (r = −0.94, p < 0.0001) and IVRT (r = −0.30, p = 0.0127), but positively with E′(VTI)/S′(VTI) (r = 0.3, p = 0.0132). In addition, E′(VTI)/S′(VTI) was negatively correlated with GWW (r = −0.35, p = 0.0032) and IVRT (r = −0.36, p = 0.0024). These associations remained significant after adjustment for sex, age and LV mass index of the subjects. In conclusion, there is an interaction between measures of LV asynchrony, myocardial work, diastolic function and its systolic–diastolic coupling in middle-aged healthy subjects. The clinical value of these interactions requires further investigation.