ABSTRACT: To assess the normal value of left ventricular twist (LVtw) and examine the changes with normal aging by 2-dimensional ultrasound
speckle-tracking imaging (STI), 121 healthy volunteers were divided into three age groups: a youth group (19–45 y old), a
middle-age group (46–64 y old) and an old-age group (≥65 y old). Basal and apical short-axis images of left ventricular were
acquired to analyse LV rotation (LVrot) and LVrot velocity. LVtw and LVtw velocity was defined as apical LVrot and LVrot velocity
relative to the base. Peak twist (Ptw), twist at aortic valve closure (AVCtw), twist at mitral valve opening (MVOtw), untwisting
rate (UntwR), half time of untwisting (HTU), peak twist velocity (PTV), time to peak twist velocity (TPTV), peak untwisting
velocity (PUV), time to peak untwisting velocity (TPUV) were separately measured. The results showed that the normal LV performs
a wringing motion with a clockwise rotation at the base and a counterclock-wise rotation at the apex (as seen from the apex).
The LVtw velocity showed a systolic counterclock-wise twist followed by a diastolic clockwise twist. Peak twist develops near
the end of systole (96%±4.2% of systole). With aging, Ptw, AVCtw, MVOtw, HTU and PUV increased significantly (P<0.05) and UntwR decreased significantly (P<0.05). However, no significant differences in TPUV, PTV and TPTV were noted among the 3 groups (P>0.05). It is concluded that LV twist can be measured non-invasively by 2-dimensional ultrasound STI imaging. The age-related
changes of LVtw should be fully taken into consideration in the assessment of LV function.
Key wordsechocardiography-speckle tracking imaging-left ventricular-twist-rotation
Journal of Huazhong University of Science and Technology 04/2012; 27(6):691-695. · 0.38 Impact Factor