Evaluation of left ventricular myocardial regional function in normal and myocardial infarction of mongrel dogs with displacement curve
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Objective To study the features of normal and infracted left ventricular regional wall motion of mongrel dogs with displacement curve, to investigate its suitable and quantitative standards of evaluating myocardial function in physiological and pathophysiological conditions. Methods Twenty-seven of the left anterior descending coronary arteries of mongrel dogs were ligated with opened chest surgery under systemic anesthesia. Activity Doppler tissue images of three cardiac cycles were obtained on apical views (2-chamber, 4-chamber, 5-chamber) before and after myocardial infarction. EchoPAC PC off-line digital ultrasound workstation was used to analyze the displacement curve at different myocardial segments of the left ventricle. All of displacement curve peaks on long axis and the time to peak were recorded. The time of starting isovolumic relaxation, and the duration of isovolumic contraction and relaxation were calculated. Results Displacement curve showed regularity in normal subjects. In myocardial infarction, peaks of all segments of anterior septum, anterior wall, apex and posterior septum were significantly lower than that in healthy subjects (P≤0.001). The duration of isovolumic relaxation was prolonged than that in healthy subjects (P0.05). Conclusion Regional wall motion abnormalities in myocardial infarction were able to be evaluated with displacement curve. The descended peak of displacement and/ or the prolonged duration of isovolumic diastole may be the early sensitive indicators of regional wall motion abnormalities in myocardial infarction.Keywords:
Isovolumic relaxation time
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Objective To evaluate the characteristics of left ventricular(LV) asynchronous contraction in patients with non-ST elevation myocardial infarction,to establish the parameters of left ventricular asynchrony. Methods The LV apical 4-chamber view of 15 normal people(control group) and 15 non-ST elevation myocardial infarction patients(myocardial infarction group) were observed with 3v probe in GE Vi Vid 9,the apical 2- chamber and the apical long-axis view were displayed using 3-plane TSI,the time to peak systolic velocity of LV12 segments(6 basal segments and 6 mid-segments) and each parameter of synchrony were measured and analyzed statistically. Results Compared with the control group, the time to peak systolic velocity was delayed in myocardial infarction group, there was significant difference. Septal-lateral delay showed that septal delay was mainly found in normal people with the longest delay time of 38 ms,while the lateral delay was mainly found in myocardial infarction patients with the longest delay time of 117 ms. There was significant difference of △TS-12(101.9 ±52.9 vs. 67.3 ±30.2,P﹤0.05)and standard deviation(34.1±18.5 vs. 22.3±11,P﹤0.05), △TS-4(62.5±36.1 vs. 35.8±24.4,P﹤0.05),△TS-6(67.2±37.1 vs. 43.1±26.1,P﹤0.05)between the two groups.Conlusion 3-plane tissue imaging is easy to operate and it can indicate the delay of left ventricular contraction quantitatively. The parameter of △TS-12 and standard deviation, △TS-6,△TS-4 can be used to evaluate the asynchrony of LV in non-ST elevation myocardial infarction patients.
Basal (medicine)
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The time-motion representation of the echogram was used to evaluate the left ventricular posterior wall motion in myocardial infarction. The left ventricular posterior wall echo was obtained in 10 normal subjects and 26 patients with chest pain admitted to a coronary care unit, including 11 with acute myocardial infarction (group 1), nine with old myocardial infarction (group 2), and six with chest pain of miscellaneous origin (group 3). The total amplitude of posterior wall excursion, left ventricular isometric contraction time, left ventricular systolic ejection time, and mean posterior wall velocity (ratio of posterior wall excursion to ejection time) were measured. By using the measurements of posterior wall excursion, mean posterior wall velocity, and isometric contraction time, group 1 patients were differentiated from those of groups 2 and 3 and from the normal subjects (all P < 0.01). The data from patients in groups 2 and 3 were not statistically different from those of normal subjects. The measurements obtained by the time-motion curve of the left ventricular posterior wall echo appear to be of value in the bedside evaluation of acute myocardial infarction.
Excursion
Coronary care unit
Posterior wall
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Objective To study the application of strain rate imaging(SRI) quantitative evaluation on myocardial infarction left ventricular regional wall motion abnormalities.Methods 20 normal cases and 20 myocardial infarction patients were obtained the dynamic images of left ventricular apical long-axis cross-section,apical four-chamber and apical two chamber view of three consecutive cardiac cycle.The SRI was applied to measure the contraction peak strain rate(PSSR),peak early diastolic strain rate(PESR),peak late diastolic strain rate(PASR) and peak systolic strain(PSS).Results Compared with those of the normal segments,the PSSR,PESR and PSS of ischemic segments were significantly reduced,and the PASR had no significant changes.Conclusions SRI parameters can be sensitive to the detection of abnormal wall motion segments of myocardial infarction patients.SRI can be used as quantitative indicator to evaluate myocardial ischemia segments.
Strain rate imaging
Strain (injury)
Cardiac cycle
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Anterior wall
Apex (geometry)
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Objective To evaluate the segmental left ventricular wall motion abnormalities after acute myocardial infarction in dogs and changes in systolic and diastolic function of infracted myocardium with quantitative tissue velocity imaging(QTVI) technology,tissue tracking imaging(TTI) technology and MRI.Method Using QTVI and TTI technology,the apical left ventricular long-axis,apical two-chamber and apical four chamber view were csanned before and 2h after coronary artery ligation in 8 dogs with acute myocardial infarction.The sample volume was placed at the bottom of the left ventricular base(Bas),mitral annulus level(Mv),the middle level of papillary muscles(Mid) and subendocardial apical(AP),synchronous sampled to obtain the left ventricular anterior wall,posterior wall,inferior wall,and the former and post-interventricular septal cardium movement along the long axis velocity curve and the displacement curve in the above-mentioned levels,to observe the systolic movement speed and displacement of each segment,and to record peak systolic velocity (Vs),peak systolic displacement(D) and peak early diastolic velocity(Ve) changes.MRI detection was made on myocardial infarction dogs,changes of infarcted myocardial wall thickness and range of motion were observed.Detection of the two types of imaging study results were compared.Results After coronary artery ligation in dogs with acute myocardial infarction,Vs and D of affected myocardium were lower than that of preligation(P0.05 or P0.01),early diastolic peak velocity reduced,and Ve lost the normal law of reduce gradually from the bottom to apex.MRI results showed a wide range of left ventricular anterior wall,the former partitions and partial inferior wall with weakened movement and thinning thickness,and regions of weakened movement and thinning thickness were concordance with the regions supplied by the left anterior descending coronary artery.Conclusion QTVI and TTI can evaluate the segmental movement and diastolic,systolic function of left ventricular myocardial infarction area sensitively,intuitively,and quantitatively,shows great significance in early diagnosis of acute myocardial infarction,also has better consistency with MRI in segmental infarction.
Interventricular septum
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Objective To evaluate the application value of two-dimensional ultrasound speckle tracking imaging(STI) in assessing mechanical changes in patients with myocardial ischemia.Methods Seventy myocardial ischemia patients and 35 healthy volunteers underwent STI examination.Peak value of longitudinal,radial and circumferential strain(LS,RS and CS) of left ventricle,and the time to peak were obtained with 18-segment model and were compared.The peak basal and apical rotation of left ventricular minor axis and the time to peak were gathered,the peak value of left ventricular whole reverse angle and time to peak were calculated.Peak angular velocity of diastole early time at apex and bottom(A-vel and B-vel) were compared between the two groups.Results Compared with control group,peak value of LS,RS and CS decreased in each ischemia stage and time to peak obviously retarded,there were statistical significant differences except posterior wall(P0.05).The peak basal and apical rotation of left ventricular minor axis and the peak value of left ventricular whole reverse angle were all smaller than those of control group,and the time to peak retarded(all P0.05).The A-vel of myocardial ischemia patients was obviously lower than that of control group(P0.05),but the B-vel were not statistical different between two groups(P0.05).Conclusion STI can quantitatively detect mechanical changes of left ventricle in patients with myocardial ischemia and assess the partial function of cardiac muscles.
Basal (medicine)
Apex (geometry)
Speckle tracking echocardiography
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Serial measurements of left ventricular posterior wall movement were made in eight patients with acute myocardial infarction by an ultrasound technique. Maximum posterior wall velocity and excursion were decreased during the first 36-hour period after infarction. In two patients a reduction in posterior wall velocity was associated with an increased pulmonary artery pressure and as the pressure returned towards normal the posterior wall motion also improved. It is suggested that this method provides a convenient, non-invasive bedside assessment of left ventricular function after acute myocardial infarction.
Ventricular Function
Anterior wall
Posterior wall
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Objective To evaluate the characteristics of the regional systolic wall motion features during isovolumic contraction time and left ventricular systolic time in dogs with acute myocardial infarction. Methods We studied 24 healthy dogs before and after acute myocardial infarction (coronary artery ligation) with quantitative tissue velocity imaging. The apical four chamber, five chamber and two chamber views were used and the sample volumes were within the endocardium. Myocardial velocity profiles were taken at the basal, mid and apical segments. Peak myocardial velocity (Vs) and time of LV segments during isovolumic contraction time and systolic time were measured. Mean acceleration was calculated during isovolumic contraction time (Aivs) and systolic time(As). Results The Vs and As were significantly reduced in the abnormal segments in the dogs during ischemia(P0.05, P0.01), while the acceleration was increased in the infarct segment and decreased in the normal segment. Conclusions QTVI objectively can sensitively quantify directional changes in the myocardial movement that are useful in evaluating regional myocardial function, and it may play a role in the detection of early myocardial ischemia.
Isovolumetric contraction
Endocardium
Systole
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Objective: This research compares longitudinal and radial direction movement characteristics bymeans ofVelocityVector Imaging(VVI),namely,the same segments of normal myocardium,infarted myocardium and non-infarcted myocardium under the resting state.Then evaluates clinical practice value of Velocity vector imaging(VVI) on coronary heart disease myocardial infarction patients segmental systolic function.Methods: Thirty healthy volunteers and thirty myocardial infarction patients were selected,andwedividedthemintothenormalgroupandthemyocardialinfarctiongroup.Weselectclearlyapicalfour-chamber,apicaltwo-chamber,apical left ventricular long axis views,axis view at papillary level,muscle level and nearly apical level.Quantitative analysis velocity(Vs),strain(S),strain rate(SR) about radial motion of left ventricle anterior septum,anterior,lateral wall,inferior,posterior wall and posterior septal;And longitudinal motion of infarction segments,non-infarcted segments and normal segments from basal segment,middle segment and apical segment.Results: From basal segment to apex,the velocity gradient descent,but the strain rate and strain are the same.Radial velocity,strain rate and strain among the different walls of the left ventricle are the same.Myocardial segmental indicators of VVI declined significantly at infracted area then non-infracted segments in its surrounding areas.Conclusions: This research indicates that VVI can be used as non-invasive diagnosis of myocardial infarction,which can help to identify or exclude the diagnosis of coronary artery disease myocardial infarction.
Apex (geometry)
Basal (medicine)
Papillary muscle
Radial stress
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