Preliminary study of energy loss in left ventricle obtained by vector flow mapping in patients with hypertension

Abstract

Objective To quantitatively analyze the energy loss (EL) in left ventricle with vector flow mapping (VFM) in hypertensive patients, and try to reveal the correlation of EL with cardiac structure and function. Methods Hypertension group: 52 hypertensive individuals were enrolled in our study, divided into 4 subgroups: ①14 patients with normal geometry(NG); ②20 patients with concentric remodeling(CR); ③15 patients with concentric hypertrophy(CH); ④3 patients with eccentric hypertrophy(EH)(not enrolled in subgroup analysis). Health control group were composed of 32 healthy volunteers. LVEF, LVMI and E/e′ were measured. And the EL in left ventricle was measured at different phases and different segments based on VFM images. Results ①EL comparison: in the phrase of late diastole(DL), isovolumic contraction(IVC) and rapid ejection(RE), compared with the control group, EL in entirety and each segment of left ventricle in hypertension group increased (P 0.05); ②Correlation analysis: in the phrase of DL, IVC and RE, EL in entirety and each segment of left ventricle showed significant positive correlations with LVMI and with E/e′ (P<0.05). In the phrase of DL, EL in entirety and each segment of left ventricle showed significant negative correlations with LVEF(P<0.05). Conclusions EL measured quantitatively by VFM is more sensitive to reflect the changes of hemodynamic in hypertensive individuals. EL is closely correlated with cardiac structure and function. Key words: Echocardiography; Hypertension; Vector flow mapping; Energy loss