Evaluation of left ventricular hemodynamic changes of patients with hypertension by vector flow mapping

Abstract

Objective To investigate the left ventricular hemodynamic changes of patients with hypertension by echocardiography using vector flow mapping (VFM). Methods Twenty-eight patients with hypertension (hypertension group) and 26 normal subjects (control group) were involved. All the subjects underwent conventional transthoracic echocardiographic examination and VFM on apical 3 chambers view. The evolution of velocity distribution, stream line and vorticity line in left ventricle were observed. Left ventricle was divided into basal, mid and apical segments, in which vorticity parameter (Vmax) were quantitatively measured and analyzed. Its relations to conventional left ventricular parameters (E, A, E/A, EDT, E/e') were then analyzed. Results ①Compared with the control group, LV end-diastolic, end-systolic volumes and E/e' significantly increased. The evolution of velocity distribution, stream line and vorticity in the hypertension group was slightly irregular. ② In mid-diastole phase, vorticity of the control group showed the trend (middle> base > apex)(P<0.05), which wasn't shown in hypertension group.In other phases, vorticity of both groups decreased from base to apex (P<0.05). ③There were statistically differences in vorticity between the two groups in early diastolic phase, late diastolic phase of apex and late systolic phase of middle (P=0.045, 0.004, 0.015, respectively). ④ There were negative correlations between Vmax in late diastolic phase of every segment and E/A (from basal segment to apex: r=-0.310, -0.334, -0.333; P=0.028, 0.020, 0.021). There was positive correlation between Vmax in isovolumic contraction time and E/e'(r=0.348, P=0.016). Conclusions VFM can be utilized to analyze left ventricularhemodynamics quantitatively and it may be a good supplement for assessing cardiac diastolic function. Key words: Echocardiography; Hypertension; Ventricular function, left; Vector flow mapping