Objective To evaluate the mechanical characteristics of systolic left ventricular(LV) transmural torsion in different LV electro-mechanical patterns using speckle tracking imaging. Methods Five open-chest canine models were employed for the acquirement of the basal, apical short-axis and four-chamber views of LV during baseline(BASE) and right atrial appendage(RAA), right ventricular apical (RVA), left ventricular lateral wall (LVL) and left ventrieular apical (LVA) pacing. Subendocardial (subend),subepicardial(subepi) and bulk rotation angle(RA) and segmental angle excursion(AE) at basal and apical level were analyzed using a dedicated workstation. LV torsion at different layers and bulk and global LV ejection fraction (EF) were calculated. Results ① There were no significant difference of transmural torsion and RA at basal and apical level between BASE and RAA pacing (P>0.05);② LV torsion of subend, subepi and bulk during RVA pacing were lower than those during RAA pacing(P0.05);LV torsion of subend and bulk during LVA pacing were lower than those during RAA pacing(P0.05);LV RA of subend,subepi and bulk at basal level during RVA and LVA pacing were lower than those during RAA pacing (P<0.05); ③ For normal electro-mechanical pattern, LV torsion of subend were significant higher than that of subepi(P<0.05), there only were a higher tendency for all pacing models (P>0.05); ④AE of segments near the pacing site decreased during different ventricle paeings (P<0.05); ⑤At BASE and during RAA pacing, LV bulk and subepi torsion were positively correlated to EF; RA of subend,subepi and bulk at basal level were positively correlated to EF. Conclusions LV transmual torsion are significantly depressed during RVA and LVA pacing. There is a spatial co-relationship between LV EF and torsion and rotation of bulk and subepi at basal level in normal LV electro-mechanical patterns.

Objeetive To evaluate the changes of left ventricular(LV) global and segmental volume, LV outlet pressure and their co-relationship, and to access LV global and segmental systolic function and mechanical asynchrony in different LV electro-mechanical patterns using full volume three-dimensional echocardiography(3DE). Methods Nineteen open-chest canine models were employed for the acquirement of LV full volume dynamic 3DE imaging during right atrial appendage (RAA), right ventricular apical (RVA), LV lateral wall(LVL) and LV apical(LVA). LV outlet end-systolic pressure(ESP) was recorded simultaneously. End-systolic volume (ESV), end-diastolic volume (EDV), global and segmental ejection fraction(EF) and systolic dyssynchrony index(SDI) of LV were measured and calculated using a dedicated workstation. The average ascending rate of LV pressure during systole(+ dp/dt) and the average descending systolic pressure(ESP), + dp/dt and - dp/dt during RVA pacing were lower than those during RAA pacing (P <0.05). SDI during RVA pacing was higher than that during RAA pacing(P<0.05). ESP, + dp/dtand - dp/dt during LVL and LVA pacing were lower than those during RAA pacing (P <0.05). There and LVA pacing was higher than that during RVA pacing (P <0.05),SD1 during LVL pacing was lower than that during RVA pacing (P <0.05), there was no significant difference of SDI between RVA and LVA and LVL pacing. Segmental EF of septum and apex during LVI. pacing were higher than those during LVA pacing (P <0.05). @Segmental EF of anterior and post septum and all apical segments (except lateral wall) during RVA pacing were lower than those during RAA pacing (P <0.05). Segmental EF of lateral and anterior wall during I.VI. pacing were lower than those during RAA pacing (P <0.05). Segmental EF of anterior wall and anterior septum during LVA pacing were lower than those during RAA parameters. Conclusions The global and minority segmental systolic function of LV during RAA pacing could be reduced compared with normal sinus rhythm. All the ventricular pacing worsen LV systolic and diastolic function compared with RAA pacing. LV systolic function during LVL pacing was superior to RVA pacing. During ventricular pacing,the systolic function at nearby segments of the pacing site was depressed.

Objective To assess subendocardial systolic circumferential strain(CS),radial strain(RS)and radial displacement(RD)of left ventricle(LV)in short-axis view and LV global systolic function in open-chest canine model with acute myocardial ischemia using velocity vector imaging(VVI),and to establish their spatial correlationships.Methods Left anterior descending coronary artery(LAD)was ligated for 20 minutes to induce acute myocardial ischemia in 12 open-chest canine model.At baseline and 20 minutes after ischemia,two-dimensional dynamic gray-scale images of three standard left ventricular short-axis views at the levels of mitral annulus,papillary muscle and apex and the images of LV apical fourchamber and two-chamber view were acquired and transfefred to VVI workstation for off-line analysis.Peak systolic CS,RS and RD of eighteen segments and of three global short-axis sections of LV were measured at subendocardium.and LV ejection fraction(LVEF)and stroke volume(SV)were calculated using Simpson's method.The differences and correlationships were analyzed between them.Resuls Compared with the value at baseline,LVEF decreased significantly(P＜0.05)after ischemia.The peak systolic subendocardial CS,RS and RD of the affected segments,global CS,RD at papillary muscle and apex views and global RS at apex view were significantly lower than those at baseline after ischemia(P＜0.05).There was a good linear correlationship between the peak systolic CS and RD of 17 segments(except the middle segment of LV lateral wall after ischemia)and each global short-axis level before and after ischemia(r=0.662-0.995,P＜0.05,P＜0.01 or P＜0.001),The peak systolic RS of six segments and each global short-axis level(except the apex level at baseline)was correlated with RD(r=0.580-0.916,P＜0.05,P＜0.01 or P＜0.001);There was not statistical correlationship between global RDs and SV as well as LVEF.Conclusions Subendocardial circumferential strain and radial displacement may sensitively reflect the changes of regional and global myocardial systolic function induced by acute myocardial ischemia.The significant correlationship between subendocardial circumferential systolic strain and radial displacement might indicate that circumferential deformation of myocardium result in the changes of the radial displacement mainly.

Objective To investigate the value of three-dimensional speckle tracking imaging(3D-STI) in assessment of left ventricular regional systolic function in acute myocardial infarction model of dogs.Methods Left anterior descending (LAD) coronary artery was ligated in 24 adult beagle dogs.Longitudinal strain(LS) of every left ventricular segment before ligation and 180 min after ligation,and the time for acquisition and analysis were obtained using two-dimensional speckle tracking imaging (2D-STI) and 3D-STI.After the experiment,left ventricular myocardium were determined by TTC staining and divided into two groups:infarcted myocardial segments and non-infarcted myocardial segments.Results Experimental model of acute myocardial infarction was established successfully in 20 dogs.After ligation,both LS of 2D-STI and 3D-STI in infarcted myocardial segments were significantly lower (P ＜ 0.01).The time for acquisition and analysis of the images by 3D-STI were significantly shorter than that by 2D-STI (P ＜0.01).The area under the ROC curve of 3D-STI was larger than that of 2D-STI.A cut-off value of-12.56％ for LS of the 3D-STI had 77.9％ sensitivity and 88.2％ specificity in predicting acute myocardial infarction.Conclusions 3D-STI is a convenient,accurate method for evaluating left ventricular regional systolic function.

Objective To evaluate the aortomitral angle(AMA)changes in primary hypertension patients with left ventricular normal configuration (LVN) by echocardiography,and explore the correlation with left ventricular systolic function.Methods LVN group included 54 patients,control group included 79 healthy subjects.All subjects were examined by conventional echocardiography,the 2-dimensional gray-scale dynamic images of 5 consecutive cardiac cycles were collected by routine echocardiography;from parasternal left ventricular long axis,the related AMA at the starting isovolumic contraction time (S-IVCT),S-wave peak(SP),starting isovolumic relaxation time(S-IVRT),and starting-end diastole(SD) were measured respectively based on the tissue Doppler imaging,calculating the angle difference(⊿θ) as well as the rate of the angle change.The global systolic longitudinal strain(GLS) and circumferential strain (GCS) of left ventricle were measured by 2-dimensional speckle tracking and quantitative analysis software.Left ventricular ejection fraction (LVEF) was measured by Simpson′s biplane method.Results Compared with control group,the ⊿θ and AMA of each phases in cardiac cycles of LVN group were increased (P<0.05);Compared with control group,the GCS of the left ventricular was increased in LVN group (P<0.05).There was a correlation between AMA of the S-IVCT and that of GLS or GCS,and the LVEF of the left ventricular in the control group (r=-0.18,P=0.04;r=-0.17,P=0.04;r=-0.19,P=0.03).Conclusions AMA angle in patients with LVN is significantly greater than the normal population value,which may be to maintain effective left ventricular systolic function and could be used as an quantitative indicator to assess the left ventricular remodeling in patients with LVN.

Objective To evaluate the relationship between the change of the aortomitral angle (AMA) with left ventricular systolic function in patients with ischemic cardiomyopathy (ICM) by echocardiography.Methods Thirty-one patients were enrolled in the ICM group,and 59 healthy subjects were selected as the control group.On the parasternal left ventricular long axis plane,AMA were measured at the R wave apex (R-AMA),J-point(J-AMA),ST-segment midpoint(ST-AMA),T-final wave (T-AMA)and P-final wave (P-AMA).The angle difference(⊿ θ) =AMAmax-AMAmin,the angle changing rate =⊿ θ/AMAmax.The global left ventricular longitudinal strain (GLS) and global circumferential strain (GCS) were obtained by 2D-speckle tracking echocardiography.Left ventricular ejection fraction(LVEF),left ventricular end-diastolic volume(LVEDV) and left ventricular end-systolic volume(LVESV) were measured using Simpson biplane method.Results The J-AMA was the largest in the control group,while the ST-AMA was the largest in the ICM group.The levels of LVEDV,LVESV and AMA in ICM group were significantly higher than those in control group,while LVEF,GLS,GCS,⊿ θ/AMAmax and ⊿ θ were decreased (P ＜0.05).In the control group,there was a correlation between T-AMA and LVEF (r =-0.349,P =0.007),and ⊿ θ was negatively correlated with GLS (r =-0.372,P =0.004).In the ICM group,⊿1 θ/AMAmax and ⊿ θ were correlated with LVEF (r =0.424,P =0.018;r =0.490,P =0.005).Conclusions AMA in ICM patients is significantly increased.The angle difference and the rate of its change are closely related to the LVEF,which is a manifestation of three-dimensional structure change of the myocardial.

Objective To evaluate the changes of peak segmental and transmural radial displacement (RD) of left ventricle(LV) during acute myocardial ischemia with different LV pacing patterns. Methods Left anterior descending coronary artery (LAD) was ligated to induce acute myocardial ischemia in open-chest Beagle canine models ( n=10). Two-dimensional gray-scale images with overlaid tissue Doppler velocity imaging in three standard LV short-axis views were acquired with different pacing patterns in a randomized sequence in three complete cardiac cycles. Parameters including peak RD, peak RD time(RD-Tc) ,the standard deviation of TC(RD-TSD) of 12 segments and their myocardial layers(subend,mid,subepi) were measured and analyzed using TDI-Q workstation. Results ① There were no significant differences of peak RD between three myocardial layers of LV wall in each different pacing pattern group;There were no significant difference of peak RD from segments and transmural layers among the different LV pacing patterns. ②With acute myocardial ischemia the RD correlation of LV lateral pacing( LVL-P) and LV border pacing(LVB-P) patterns were higher than that of LV apical pacing(LVA-P) pattern between global segment and its subend, mid, subepi. ③ RD-Tc of 12 LV segments and their subend, mid, subepi appeared after T wave and there were no significant differences of RD-Tc among different LV pacing patterns. ④RD-TSD of the corresponding segments during LVL-P,LVA-P and LVB-P patterns were significant lower than those during acute yocardial ischemia(P<0. 05). Conclusions The existed RD correlation of LVA-P between subend.mid, subepi and the segment were lowest among the different ischemic LV pacing patterns; the synchronization of transmural RD could be recovered partly with LVL-P, LVA-P and LVB-P patterns. The echocardiographic study of LV transmural RD might be useful to reveal the segmental and the transmural myocardial mechanical state with different LV pacing patterns during acute ischemia in detail.