Objective To reveal the potential different longitudinal motion characteristics and differences of left and right muscular band (L-MB,R-MB)of interventricular septum (IVS) during systole and diastole in normal subjects.Methods Dual Doppler tissue imaging was applied for the longitudinal velocity curves of L-MB and R-MB of anterior and posterior interventricular septum(P-IVS,A-IVS) at basal,mid,and apical levels in eighty-two healthy subjects.Peak isovolumetric contraction (VIVC),systolic (Vs),early(Ve) and late (Va) diastolic velocities were measured,and myocardial velocity gradient(MVG)and Ve/Va ratio of each segment of L-MB and R-MB were calculated.Results ①Peak velocity of MB:the VrvC,Vs,Ve and Va of R-MB of both A-IVS and P-IVS were higher than those of L-MB; the VrvC,Vs,Ve and Va were gradually decreased from the base to apex of both A-IVS and P-IVS;the VIVC and Vs of A-IVS were higher than those of P-IVS; the Ve and Va of A-IVS were lower than those of P-IVS.②Correlation and MVG analyses of peak velocity of MB:the systolic and diastolic velocities between L-MB and R-MB of both A-IVS and P-IVS have shown a very strong positive correlation;the isovolumetric systolic MVG1 of L-MBof A-IVS,systolic MVG1 of R-MB of P-IVS and the diastolic MVG1 of both A-IVS and P-IVS were higher than those of MVG2.Conclusions The heterogeneity of longitudinal peak systolic and diastolic velocity and regional myocardial compliance,the consistency of moving direction and positive correlation of longitudinal peak systolic and diastolic velocity between L-MB and R-MB of both A-IVS and P-IVS have been demonstrated in normal subjects.

Objective To evaluate regional myocardial mechanical dysfunction of left ventricle in patients with ECG T-wave inversion using echocardiographic velocity vector imaging.Methods One hundred nineteen female patients with T wave inversion divided into three groups:V1-6 T-wave inversion group(52 patients),V1-4 Twave inversion group (33 patients),V3-6 T-wave inversion group (34patients),while selected 44 healthy women in control group.Peak systolic radial strain (SRSmax) and strain rate (SRSrmax),peak systolic circumferential strain (SCSrmax) and strain rate (SCSmax) were derived and compared from three short-axis views of left ventricle at 18 wall segments using a dedicated Syngo VVI software and workstation,and the depth of T-wave inversion in different precordial lead was measured and correlated with mechanics parameters between four groups.Results In V1-6 T-wave inversion group,each mechanical variable of anteroseptal,anterior,anterolateral and inferolateral walls decreased (P ＜0.05-0.01).In V1-4 T-wave inversion group each mechanical variable of anteroseptal,anterior and inferoseptal walls declined (P ＜0.05-0.01).In V3-6 T-wave inversion group four mechanical variables(i.e.,SRSmax SRSr SCSmax and SCSrmax) of anteroseptal,anterior,anterolateral and inferolateral walls reduced,mainly at basal segment (P ＜0.05-0.01).The ventricular segments of reduced SRSmax,SRSrmax and SCSrmax in V1-6 T-wave inversion group and of SRSrmax in V3-6 T-wave inversion group were more than those in V1-4 T-wave inversion group (P ＜0.05-0.01).In V1-6 T-wave inversion group,negative correlationships between radial mechanical variables of anteroseptal wall and the depths of V4 and V5 lead T-wave inversion were found (r =-0.29--0.37,P ＜0.05-0.01).Otherwise a positive correlationships between SCSmax of anterolateral wall and the depth of V3 lead T-wave inversion were established (rs =0.44,P =0.01) in V1-4 T-wave inversion group.Conclusions There is a regional myocardial dysfunction of LV in female patients with ECG T-wave inversion.The extent of electrical repolarization abnormality is correlated to the severity of regional myocardial dysfunction.

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Objective To study regional myocardial function of right ventricle at different stages of cirrhosis,using velocity vector imaging combined with standard isometric grip strength test to reveal the mechanical function in patients with liver cirrhosis at early stage further,and to benefit reliable quantitative evaluation and efficacy indicators for the establishment of the early diagnostic criteria of cirrhotic cardiomyopathy by echocardiography,and found myocardial mechanics basis for explicit pathogenesis of cirrhotic cardiomyopathy.Methods Accorded to Child-Pugh score,the cirrhosis experimental groups were divided into three groups:group A (42 patients),group B (28 patients) and group C (12 patients).There were 31 patients in group A to be conducted standard isometric grip strength test.While 34 healthy people were selected as the control group.The dynamic gray scale long-axis view images of the right ventricle were collected in 3 complete cardiac cycles in apical four-chamber view.Peak systolic longitudinal strain (Smax) and global ejection fraction of the right ventricle were derived from 6 myocardial segments with the Syngo VVI workstation off-line.Results 1)Compared with the control group,in group A,global ejection fraction of the right ventricle was normal,there were not significant change of Smax of each segment (P ＞0.05).In group B,there was not significant change of global ejection fraction of the right ventricle,the Smax of each segment were increased mainly (P ＜0.05-0.01).In group C,global ejection fraction of the right ventricle was significantly lower (P ＜ 0.01),the Smax of each segment reduced mainly (P ＜ 0.05-0.01).2)Compared with group A,in group B,there was no significant difference of blood pressure and global ejection fraction of the right ventricle,while including the Smax of each segment in systole and diastole.Compared with group A and group B,in group C,systolic and diastolic blood pressure and global ejection fraction of the right ventricle decreased significantly; the Smax of each segment were reduced mainly (P ＜ 0.05-0.01).3)Compared with the resting state,after the standard isometric grip strength test,the global ejection fraction of the right ventricle decreased significantly,there was a significant reduction mainly in Smax of each segment (P ＜ 0.01).Conclusions The regional myocardial function of right ventricle in patients with liver cirrhosis is abnormality even at early stage and could be revealed by standard isometric stress test.The right ventricular systolic dyfunction is related to the stages of liver cirrhosis disease.

Objective To evaluate the characteristic of left ventricular rotation and twist in healthy adults using ultrasonic velocity vector imaging(VVI),and to discuss its biomechanical mechanism. Methods In 70 healthy adults, the rotational characteristic of left ventricular subendocardium and subepicardium at 3 differently standard shot-axis levels and 18 differently myocardial segments, and the torsional characteristic of left ventricular wall were evaluated via ultrasonic VVI. The maximum rotation angle(Rmax)at different sites of left ventricular wall and the maximum twist angle(Tmax)between left ventricular subendocardium and subepicardium in a completely cardiac cycle were compared respectively. Correlation tests were performed between left ventricular Tmax and the Rmax at different short-axis levels of left ventricular wall.Results ①To be compared with other myocardial segments, Rmax was smallest at antero-septal or anterior wall of the same left ventricular short-axis level(P>0.05).②The mainly rotational directions of the basal leveI and the apical level of left ventricular wall in a completely cardiac cycle were adverse.To be compared with basal or apical level of left ventricular wall,Rmax was smallest at papillary muscle level(P<0.05).and there was no statistical significance in Rmax between basal and apical level.There was positive colinearity between left ventricular Tmax and the Rmax of basal or apical level (P<0.01),but zero correlation was found between the Tmax and the Rmax of papillary muscle level.③Rmax of left ventricular subendocardium was bigger than that of subepicardium(P<0.01).Tmax of left ventricular subendocardium was bigger than that of subepicardium[(11.44±4.82)°vs(7.05±3.90)±,P<0.01].Conclusions Twist of left ventricular wall in healthy adults appeared the torsional characteristic of thin-wall cylinder.Elucidation of the biomechanical mechanism of cardiac twist is promising if basing on the principle of biomechanics.

Objective To develop an in vivo procedure f or His bundle pacing (HBP) and radio-frequency (RF) ablation of the atrio-ventricular node (AVN) guided by intracardiac echocardiography (ICE) and tissue Doppler imaging (TDI). The procedure included a custom designed bipolar active fixation pacing lead and steerable delivery catheter, and a commercial RF generator and ablation catheter. Methods Six anesthetized- closed-chest canines were tested. The anatomy in the His bundle and AVN regions, and the onset of myocardial electro-mechanical activation were identified using ICE and TDI. The lead and RF ablation catheter were navigated using an ICE catheter (for local detailed imaging) and fluoroscopy (for global imaging). Surface QRS morphologies were recorded to confirm HBP and third degree block post-ablation. Results Direct His bundle pacing was achieved in one canine, and His + ventricular septal pacing in the remaining five. QRS width in sinus rhythm and HBP were ( 59.7-? 5.3-)ms and ( 82.8-? 16.6-)ms separately (P= 0.02-). The increased QRS width for HBP was due to early septal activation. HBP thresholds were ( 3.0-? 1.0-) volts at 0.5 ms (N=5 due to a late exit block). The mean procedure durations were: HBP 40 minutes (3 to 81 minutes), AVN ablation 3 minutes (2 to 5 minutes), and total X-ray exposure 13 minutes (1 to 55 minutes). Post-mortem analysis of the lead and ablation lesions confirmed correct anatomic localization for HBP and AVN ablation. Conclusions ICE provides precise anatomic guidance of HBP lead implantation and AVN ablation and can significantly reduce exposure to fluoroscopy.

Objective To observe left ventricular transmural peak radial strain and strain time-to-peak of peri-infarct different layers myocardium using tissue Doppler strain imaging, to assess its mechanical pattern during acute myocardial ischemia.Methods Left anterior descending coronary artery (LAD) were ligated in experimental open-chest Beagle dog models (n = 9),the two-dimensional apical short-axis views of left ventricle in three complete cardiac cycles were acquired and stored in TDI-Q workstation at baseline(the control group of peri-infarc myocardium) and during acute myocardial ischemia respectively.Sampling volume was uesd to measure the peak radial strain and the strain time-to-peak consesquently on the derived M -mode tissue Doppler velocity images at peri-infarct myocardium before and after ischemic segments and different layers(subendocardium, medium, subepicardium).Statistical analies was performed using student's t- test or Pearson's correlations.Results Peak radial strain decreased at peri-infarct subendoeardium (P<0.05) with no significant difference between those at baseline and at peri-infarct medium (P >0.05), the peak radial strain increasd at peri-infarct subepieardium (P < 0.05) ,and the strain time-to-peak at different layers of peri-infarct myoeardium was significantly postponed (P< 0.05).There was a good correlationship of peak radial strain between subendocardium and segment as well as between the medium and segment (r = 0.617, P<0.01 ; r = 0.556, P<0.01).This correlationship disappeared at peri-infarct myocardial segment (r = 0.287, P > 0.05, r = 0.243, P > 0.05).Conclusions The left ventricular transmural mechanical remodeling at peri-infarct myocardium is the integrant of result of mechanical interactions between ischemic and nonischemic myocardium,which might be one of the trigger the structural and fundational remodeling processes involving in the pathophysiological foundation of ischemie cardiomyopathy.

Objective To assess longitudinal segmental myocardial strain(?),displacement(D) and the changes of the inner dimension of left ventricle(?L),and to establish their spatial correlationship during cardiac pacing and conductive block.Methods The standard apical four chamber view of left ventricle were acquired during cardiac pacing(n=12),right bundle branch block(RBBB,n=13) and sinus rhythm(n=14) using GE Vivid 7 dimension and the M3S probe with(4.0) MHz for the analysis of the longitudinal myocardial segmental(apical and basal segments) ? and D of left ventricle with two dimensional strain analysis software.The maximal and change longitudinal dimension of left ventricle was measured and calculated at end-diastole and end-systole respectively.The differences of the above parameters were compared and the spatial correlationships among them were analyzed.Results The peak ? of the septal basal segment during cardiac pacing was significant higher than that of the apical segment.There were significant differences in the peak D and(?D)(D_(basal)-D_(apical)) at lateral wall among sinus rhythm,RBBB and pacing group(P

Objective To detect stunned myocardium using low-dose dobutamine stress (DBS)combined with two-dimensional speckle tracking imaging (2D-STI),and to evaluate the difference and characteristics of mechanical parameters in different conditions between stunned myocardium and adjacent normal myocardium.Methods The acute myocardium ischemia/reperfusion (I/R) of anterior wall of left ventricle(LV) was induced with 60 minutes ligation of left anterior descending coronary artery (LAD),and with reperfusion of 120 minutes in 10 open-chest beagle dogs.Dobutamine was administered continuously via vein with two different dose of 5 μg · kg-1 · min-1 and 10 μg · kg-1 · min-1.At baseline,post ischemia/reperfusion,after the first DBS and the second,the gray-scale dynamic images of three cardiac cycle of left ventricular short axis at the levels of mitral annulus,papillary muscle and apex were acquired.The systolic peak of circumferential strain (CS),radial displacement (RD) of eighteen segments of subendocardium and subepicardium were analyzed by Speckle tracking workstation.LV end-systolic dimension(LVIDS),LV end-diastolic dimension (LVIDD),LV eject fraction (LVEF),heart rate (HR),aortic valve forward flow velocity time integral(AV-VTI) were also measured.Results ①There was no statistical significance (P ＞0.05) under the conditions of baseline,post I/R,the first DBS and the second for LVIDD,LVIDS,LVEF,HR and AV-VTI.②Compared with baseline,the peak systolic subendocardium and subepicardium CS,RD decreased significantly at the apex and middle of short-axis anterior wall of LV under the conditions of post I/R;The parameters of the first DBS was significantly increased compared with the I/R (P ＜ 0.05) ; There was no difference between the two DBS and baseline(P ＞0.05).The peak systolic subendocardium and subepicardium CS,RD at the bottom segment of LV were no statistical significance under the four conditions.③There was no difference for anterolateral wall and anterior septum of LV at the level of papillary muscle under the four conditions.Conclusions ①Low-dose DBS combined with two-dimensional speckle tracking imaging can detect stunned myocardium accurately.② After the occurrence stunning myoeardium,the peak systolic subendocardium RD decreased slightly,subepicardium RD was normal,the subendocardium CS of the surrounding myocardium was still normal,and the peak systolic subepicardium CS decreased to some degree.