To date, most studies about strain and strain rate (SR) are based on Doppler tissue imaging (DTI), which is dependent on the angle between ultrasonic scan line and tissue. Velocity vector imaging (VVI) is a new echocardiographic method based on two-dimensional gray scale imaging, which is angle-independent and can provide more information about cardiac function than DTI.
To assess regional myocardial SR in hypertensive patients with left ventricular hypertrophy (LVH) but normal global ejection fraction (GEF) and fractional shortening (FS) using VVI.
Using VVI, two-dimensional images were performed in 20 hypertensive patients with LVH and 20 normal control subjects. The segmental systolic peak SR (SRs) in the short-axis view and the apical SRs in the long-axis view were analyzed by offline software.
The segmental SRs in the long-axis and short-axis views were significantly lower in the LVH group than in the corresponding segments of the control group. There was no significant difference between the circumferential SRs of different segments in the short-axis view in the LVH and control groups. The circumferential SRs decreased significantly from the endocardium to the middle layer of the myocardium in the short-axis view in the LVH group and in the control group.
Hypertensive patients with LVH may have regional LV systolic function impairment despite having normal GEF and FS. The GEF and FS were not the decisive factors of myocardial systolic function in the present study. There was an obvious systolic gradient from the endocardium to the middle layer of myocardium in circumferential SRs in the short-axis view. VVI can be used to accurately recognize and quantify abnormalities of regional myocardial deformation.