The Study On Left Ventricular Twisting And Untwisting In Hypertensive Patients Using Speckle Tracking Imaging

Objective:To investigate the character of left ventricular twist and untwist in hypertensive patients with different geometric left ventricle (LV) using two-dimensional speckle tracking imaging (STI). To evaluate the clinical importance for assessing LV systolic and diastolic performance of hypertensive patients.Methods:The enrolled include159patients with hypertension. According to left ventricular geometry, all patients may be classified into the following three mutually exclusive groups on the basis of left ventricular mass index and relative wall thickness:normal geometry (normal LVMI and normal RWT) group (n=70), concentric remodeling (normal LVMI and increased RWT) group (n=53), and concentric hypertrophy (increased LVMI and increased RWT) group (n=36). A total of56age-and sex-matched non-hypertensive participants served as control subjects.The Vivid7dimension system (GE Healthcare) was used, which was equipped with a M3S probe (1.7～3.4MHz). Basic measurements included left ventricular diastolic dimension (LVDd), left ventricular systolic dimension (LVDs), interventricular septal thickness (IVST), and left ventricular posterior wall thickness (LVPWTd). The RWT, LVMI and FS were calculated. The left ventricular ejection fraction (LVEF) was calculated according to the biplane Simpson rule. The peak velocity of early rapid filling wave (E-wave velocity) and peak velocity of the late filling wave due to atrial contraction (A-wave velocity), E deceleration time (EDT), E/A velocity ratio, lateral A diastolic mitral annular velocity (Aa), lateral E diastolic mitral annular velocity (Ea), Ea/Aa, E/Ea, isovolumic relaxation time (IVRT), and cardiac cycle (CC) were measured using mitral inflow conventional Doppler and TDI pulsed wave data from the lateral annulus echocardiography. Acquisition of specific short-axis planes was guided by internal landmarks:the presence of the mitral valve, and the apical plane was acquired distally to the papillary muscles. Using2D strain software, apical peak rotation (PAR), basal peak rotation (PBR), LV peak twist (Ptw) and the time to peak were measured separately. Twist at aortic valve closure (AVCtw), twist at mitral valve opening (MVOtw), untwisting rate (UntwR), and half time of untwisting (HTU) were calculated.Results:1. Compared with normal controls, apical and basal LV rotation and LV twist curve during one cardiac cycle of the hypertensive patients with different geometric LV were generally consistent, while PAR and Ptw were increased in hypertensive patients (p<0.05).2. Compared with control group and normal geometry group, E/A and Ea/Aa was decreased, EDT increased in concentric remodeling group and concentric hypertrophy group (p<0.05). No significant differences in E/A, Ea/Aa and EDT was observed between control group and normal geometry group, concentric remodeling group and concentric hypertrophy group (p>0.05). Compared with concentric hypertrophy group, E/Ea was reduced in the other three groups (p<0.05). No significant differences in E/Ea among control group, normal geometry group, and concentric remodeling group (p>0.05).3. Between four groups, PART、 PBR、 PBRT、 PtwT and HTU showed no significant differences, measured by STI (p>0.05). Compared with control group, PAR, Ptw, AVCtw, MVOtw were higher, and UntwR was lower in three hypertensive groups (p<0.05), but there were no significant differences between these hypertensive groups (p>0.05).4. A positive correlation was showed between Ptw and PAR, and a negative correlation was showed between Ptw and PBR (r=0.844, r=-0.519, p<0.05) in hypertensive patients.5. Ptw was no significant associated with LVEF, FS, EDV, ESV, SV, CO, CI and UntwR (p>0.05). UntwR was no significant associated with E/A, Ea/Aa and E/Ea (p>0.05).Conclusion:1. Left ventricular twist and untwist had changed before geometric abnormality, and could be appropriate index for accessing the degrade of left ventricular function in hypertensive patients.2. Ptw can be one of the new indexes to assess left ventricular systolic function more exactly than LVEF and FS.3. UntwR might be a more sensitive indicator of left ventricular diastolic performance than conventional indices such as E/A, Ea/Aa and E/Ea.4. Whether the rotation of apical can entirely instead of LV peak twist served as a useful diagnostic tool should be studied.5. The relationship between Ptw and UntwR, LVEF, or FS and between UntwR and E/A, Ea/Aa, or E/Ea should be assessed by increasing the number of the samples for further research.