| Although the studies of the cardiac structers and functions have developed to cellular and molecular level,people haven't known clearly about the left ventricular muscles until the concept"ventricular myocardial band (VMB)"came. It gives us a new viewpoint to explain the cardiac structures and function.The concept considers that the heart, in reality, is a myocardial band which includes a dual-spiral formation, an apical loop and a basal one. The basal helix circumvolutes right ventricle and the base of left ventricle. The muscular fibers goes from outside in, in a clockwise way, and from inside out, in a counterclockwise direction in apical helix,called descendent segment (DS) and ascendant segment (AS). This form of ventricular architecture can develop a corresponding functional reality. The cardiac anatomy relates to its contracting and relaxing, or more specifically, constricting to narrow and eject, and dilating to widen and fill. The concept enhances us the recognization of the cardiac anatomic structures, gives us a new viewsight to understand the myocardial pathological changes, such as the pathogenesis of dilated myocardiosis, chronic heart failure, and so on. With the development of the recognizations of cardic anatomy, clinical imageology about cardic biodynamics has penetrated into spacial deformation during its process in recent years, and torsion is one of the spacial deformations.Left ventricular (LV) twist deformation defined as the wringing motion of the heart as the apex rotates with respect to the base around the LV long axis. LV twist has an important role for both LV systolic and diastolic function. Since 1682 William Harvey described the LV torsional deformation, more and more studies have focused on it. Recently tagged magnetic resonance imaging (MRI) has shown great promise to assess the torsional deformation, but this equipment has lower frame frequency and high expenses, thus, precluding its use in routine clinical practice. Using tissume strain and strain rate imagingd can assess the cardiac one-dimensional, LV longitudinal deformation, but the technique is angle-depended. The recent development of 2-dimensional (2D) ultrasound speckle tracking imaging (STI) can recognize and track tissue motion by tracking the movement of the speckle pattern produced by the backscattering of the ultrasound itself, so it can evaluate the LV strain, rotation, and displacement noninvasively, and can analyse the characters of the cardiac movement mechanics. STI can analyze the characteristics of ventricular torsion in normal and various pathologic states, representing a new and powerful method for quantifying globle or partly ventricular movement mechanics. Lots of studies have approved that STI has high relativity with technique MRI, DTI in assessing the LV rotation.The paper is divided into three sections. In the first section, the left ventricular systolic twist in healthy adults were evaluated by two- dimensional ultrasound STI, and its relative factors were analysed.The research ulteriorly confirmed the STI in assessing the LV tortion noninvasively.In the next two sections,we explored the LV torsion in diabetic and anterior old myocardial infarction respectively, hoping to find the abnormity of the LV function in forpart, helping the clinical diagnosis, treatment and prognositic assessment for coronary heart diseases.Section I Evaluation of the Left Ventricula Systolic Twist in healthy adults by Two-Dimensional Ultrasound Speckle Tracking ImagingObjective: To evaluate the characters of left ventricular twist(LVtw) in healthy adults by 2-dimensional ultrasound speckle-tracking imaging(STI), to study the relationship between the twist and conventional echocardiographic parameters of LV function, and to explore the effects of some physical factors on LVtw, such as aging, sex,and body mass index.Methods: A total of 82 healthy(43 women and 39 men, average age 50.7±18.9 years) volunteers were recruited .Echocardiography was performed and some conventional parameters on LV function were gotten, including ejective fraction(EF), short fraction(FS), stroke volume(SV), E/A velocity ratio, E-wave decending time(E-DT), E-wave acceleration time (E-AT)and E-wave acceleration(E-acc). Two-dimensional LV short- axis images at basal and apical levels were acquired using second harmonic mode. Care was taken to ensure that the basal short-axis planes contained the mitral valve, and that the apical plane was acquired distally to papillary muscles. Digitals stored in a hard disk for offline analysis using the Echopac software. The software algorithm automatically segmented the LV short axis into 6 equidistant segments (anteroseptal, anterior, lateral, posterior, inferior and interventricular septum), finally it could calculate the time domain LV rotation automatically for each segment in both short-axis planes. From the profiles, we could calculate some parameters, such as the peak of left ventricular twist(Ptw), peak twist velocity (PTV), rate of untwisting (Untw R).We analysed the characters of LVtw in healthy volunteers and its relative factors. LV twist and twist velocity were defined as apical rotation and rotional velocity relative to the base. Counterclockwise rotation as viewed from the LV apex was expressed as a positive value, whereas a clockwise rotation as a negative value. The degree of untwisting , the directional reversal of systolic counterclockwise twist during diastole, was expressed as percentage of maximum systolic twist, because isovolumic relaxation time (IVRT) interval varied from volunteer to volunteer, the adjustive untwisting rate(Untw R)was defined as〔(Tw AVC-Tw MVO)/TwAVC×100〕/IVRT,where TwAVC is twist at aortic valve closure,TwMVO is twist at mitrial valve open.Results: 984 segments were analyzed totally, there were 21 segments tracked unacceptable, and four volunteers were excluded because of three or more unacceptable segments in each. At last, a total of 78 volunteers were enrolled. (1) Seen from the apex, the normal LV performs counterclockwise rotation mainly at the apex (6.79±3.47)°and a clockwise rotation mainly at the base (-6.01±2.22)°. The LV had a mainly counterclockwise rotation in whole (12.40±4.17)°. The LVtw velocity shows a systolic positive velocity(127.71±40.36)o and a diastolic negative velocity (-111.26±38.92)o. There was no significant difference in Ptw and PTV among different segments. (2) In healthy volunteers, SV, LVEF, FS were correlated positively with LVtw, (r=0.62, 0.62 and 0.88, P<0.05),LVEF positively with PTV.( r=0.59,P<0.05) and E-DT negativly with Untw R(r=-0.71, P<0.05). (3) Age were correlated positively with Ptw(r=0.68, P<0.05), but negatively with Untw R(r=-0.70, P<0.05).To examine the effect of aging on twisting, the healthy volunteers were divided into 3 groups according to age (young, 18-45years; middle aged, 46-64 years; older,≥65years), then we compared the diffences in LVtw . Ptw was significantly greater in the older group (15.67±2.08°) compared with young (12.56±3.57°, P<0.05) and middle-aged(13.67±2.84°, P<0.05)groups,but there was no significant differences in Ptw between young and middle-aged groups (P>0.05); Untw R were significantly lower in the older (0.45±0.27%/ms) and middle-aged (0.52±0.24%/ms) groups compared with young group (0.59±0.33%/ms),(P<0.05);No difference was noted in PTV among the 3 groups.(P>0.05)。Body mass index and HR had no significant correlation with Ptw,PTV or Untw R(P>0.05)。No sex difference was noted in Ptw, PTV or Untw R.Conclusion: 2-dimensional STI has the potential for evaluating LV twist noninvasively. LV torsional motion can give novel insights into LV function. In healthy volunteers, SV, LVEF, FS were correlated positively with LVtw and E-DT negativly with Untw R. The age-related changes of LVtw should be fully taken into consideration when assessing LV function.Section II Clinical Study of Left Ventricular Twist in Type 2 diabetic Patients by Two-Dimensional Ultrasound Speckle Tracking ImagingObjective: To evaluate the LVtw in patients with 2 type diabetes by 2-dimensional ultrasound STI, explore the relationship between the LV diastolic function and the LVtw.Methods: 37 patients with type 2 diabetic mellitus (17 women and 20 men, average age 48.3±10.1 years) and 24 age-matched asymptomatic healthy volunteers (8 women and 16 men, average age 50.6±7.9 years) were recruited. The patients'blood glucose was well controlled within normal level. The diabetic patients were divided into 2 groups according to Em/Am by tissue Doppler imaging (group A, normal diastolic function, Em/Am﹥1; group B , abnormal diastolic function, Em/Am≤1), Two-dimensional and Doppler Echocardiographic examination were performed and some parameters were gotten, including LV ejective fraction(EF), peak mitral flow velocity of the early rapid filling (E) wave velocity , peak velocity of the late filling wave due to atrial contraction(A) wave velocity, E/A velocity ratio, E-wave decending time (E-DT) ,E-wave acceleration time (E-AT), E-wave acceleration (E-acc) and isovolumic relaxitive time (IVRT)。Two-dimensional LV short- axis images at basal and apical levels were acquired using second harmonic mode. Digitally stored in a hard disk for offline analysis using the Echopac software. The software could calculate the time domain LV rotation automatically for both short-axis planes. From the profiles, We could calculate some parameters, including Ptw, TwAVC, TwMVO, time to peak twist velocity(TPTV), Untw R, peak untwist velocity(PUV) and time to peak untwist velocity(TPUV). We compared the diffences of the parameters among the three groups. LV twist and twist velocities were defined as apical rotation and rotional velocities relative to the base. Counterclockwise rotation as viewed from the LV apex was expressed as a positive value, whereas a clockwise rotation as a negative value. The adjustive Untw R was defined as〔(Tw AVC - Tw MVO)/TwAVC×100〕/IVRT.Results: 732 segments were analyzed totally, there were 29 segments tracked unacceptable (3.96%), and four volunteers were excluded because they had 3 or more unacceptable segments. At last, a total of 57 volunteers were enrolled (group A, 16 diabetic patients, group B, 20 diabetic patients, and 21 healthy volunteers). (1) Diabetic patients had the same shape in LV torsional curve and LV torsion-velocity curve. (2) Ptw was significantly greater in the diabetic group B (16.53±3.96°), compared with diabetic group A (15.63±2.48°, P< 0.05) and healthy volunteers (12.66±2.96°, P< 0.05) group,but there was no significant difference in Ptw between diabetic subgroups (P>0.05);(3)Untw R were significantly lower in diabetic group B (0.40±0.17 %/ms) and group A(0.45±0.21%/ms), compared with healthy volunteers (0.61±0.29%/ms), (P< 0.05);PUV in diabetic group B and group A(- 125.72±45.33°/s and -116.41±34.09°/s respectively ) were higher than healthy volunteers(-109.30±32.57°/s)group, the difference also was noted in the two subgroups(P<0.05. No difference in PTV were noted among the 3 groups (P>0.05).Conclusion: STI has a potential ability to evaluate the early change of LV function in patients with diabetes mellitus by measuring the twist of left ventricular. Systolic twist is increased and diastolic untwisting is depressed in type 2 diabetic mellitus.Section III Assessment of Global and Regional Left Ventricular Twist in Patients with Anterior Wall Myocardial Infarction by Speckle Tracking ImagingObjective: To evaluate the global and regional left ventricular twist (LVtw) in patients with anterior wall myocardial infarction (MI) by 2-dimensional ultrasound speckle-tracking imaging(STI), explore the relationship between the LV systolic function and the LVtw. Methods: 29 patients with old anterior wall MI (12 women and 17 men, average age 62.7±7.4 years) and 22 age-matched asymptomatic healthy volunteers (9 women and 13 men, average age 64.9±6.1 years) were recruited. The MI patients were divided into 2 groups according to theirleft ventricular ejective fraction(LVEF) (group A, LVEF﹥45%; group B, LVEF≤45%), Echocardiographic examination were performed and some parameters were gotten, including LVEF, short fraction(FS), left ventricular end-diastolic distance (LVEDd).Two-dimensional LV short- axis images at basal and apical levels were acquired using second harmonic mode. Digitals stored in a hard disk for offline analysis using the Echopac software. The software algorithm automatically segmented the LV short axis into 6 equidistant segments (anteroseptal, anterior, lateral, posterior, inferior and interventricular septum), finally it could calculate the time domain LV rotation automatically for each segment in both short-axis planes. From the profiles, we could get some parameters, such as the peak of left ventricular twist (Ptw) peak twist velocity (PTV). We analysed the characters of LVtw in MI, found the diffences of the parameters among the three groups. LV twist and twist velocity were defined as apical rotation and rotional velocity relative to the base. Counterclockwise rotation as viewed from the LV apex was expressed as a positive value, whereas a clockwise rotation as a negative value.Results: 612 segments were analyzed totally, there were 31 segments tracked unacceptable (5.1%), six persons were excluded because they had 3 or more unacceptable segments. At last, a total of 45 volunteers were enrolled (group A, 15 patients, group B, 10 MI patients and 20 healthy volunteers).(1) The global Ptw was significantly decreased in group B (8.03±4.89°) compared with group A (11.38±3.11°,P<0.05) and healthy volunteers group (12.77±2.67°, P< 0.05) there was no significant diffence in global Ptw between group A and volunteers group(P>0.05);The global PTV in group B (100.62±21.41°/ms)was depressed compared with group A (125.57±37.01°/ms, P< 0.05) and healthy volunteers group (127.52±35.54°/ms, P<0.05). (2) The apical Ptw in group A (5.04±1.76 o) was decreased compared with healthy volunteers group(6.74±1.90 o) (P<0.05). Ptws in both apical and basal level were reduced compared with group A and healthy volunteers (P< 0.05); (3) Ptws of anterior wall and anterior-septal wall were significantly reduced in group A with MI than normals[(10.34±1.85o) vs (12.01±2.35o) and (9.34±1.94o) vs (11.57±3.01 o)] (P<0.05). Compared with group A and healthy volunteers group, regional PTV and Ptw show a significant decreasing (P<0.05).Conclusion: Systolic twist was decreased in accordance with LV systolic dysfunction in anterior wall MI. STI has a potential ability to quantification of LV global and segmental twist in patients with MI.
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