Characterization of left ventricle energy loss in healthy adults using vector flow mapping: Preliminary results

Energy loss (EL) is a new quantitative hemodynamic index based on vector flow mapping (VFM). This study aimed to characterize EL of the left ventricle (LV) in healthy adults.

Fifty-one healthy adults were enrolled in this study. EL of LV was analyzed frame by frame using color Doppler images of a standard apical three-chamber dynamic view on an offline VFM workstation. The average EL of systole and diastole was calculated, and the results were averaged over three cardiac cycles.

The average EL for systole and diastole was 11.07±5.82J/m/s and 11.58±5.54 J/m/s, respectively. Multivariate regression analysis showed that the aortic velocity time integral (AOVTI), A-wave peak velocity, and isovolumetric contraction time (IVCT) were independently associated with the average systolic EL. E-wave peak velocity, height, and IVCT were independently associated with the average diastolic EL. For females, the average systolic and diastolic EL was 12.66±7.06J/m/s and 13.90±5.37J/m/s, respectively. For males, the systolic and diastolic EL was 9.29±3.33J/m/s and 8.97±4.55J/m/s, respectively.

Energy loss in LV changes regularly during the cardiac cycle. The average systolic EL has a high positive correlation with AOVTI, whereas the average diastolic EL has with E-wave peak velocity. Women have higher average EL than men in both systole and diastole. By recognizing the EL characterization of healthy adults, the variation in EL may reflect cardiac dysfunction. These were preliminary results, and thus, the clinical implications of EL warrant further investigation.