Doppler tissue velocity, strain, and strain rate imaging with transesophageal echocardiography in the operating room: a feasibility study.

OBJECTIVE: Transesophageal echocardiography (TEE) is increasingly used to monitor regional myocardial function during cardiac operation. Doppler myocardial imaging (DMI) indices can potentially provide new information on regional radial and longitudinal myocardial motion and local deformation. This study examined the feasibility of TEE acquisition of regional radial and longitudinal velocity, displacement (D), strain, and strain rate data during cardiac operation and evaluated the effects of sternotomy and pericardial opening on these indices. METHODS: After a baseline transthoracic echocardiographic study, TEE was performed in 22 patients (age 64 +/- 7 years) before sternotomy, after sternotomy with intact pericardium, and after pericardial opening. Regional DMI velocity analysis was performed for the transgastric anterior and inferior walls midpapillary segment (radial function) and the 4-chamber septum and 2-chamber inferior walls basal, mid, and apical segments (longitudinal function). For each segment, systolic and diastolic velocity were derived and D, strain, and strain rate calculated. RESULTS: Transthoracic echocardiographic study and TEE provided similar data from an equivalent number of interpretable segments. In the basal and mid septum, maximum longitudinal systolic D decreased with pericardial opening (basal septum pericardium closed: 6.6 +/- 1.5 mm, open: 4.6 +/- 1.8 mm, P =.007; midseptum pericardium closed: 4.7 +/- 2.5 mm, open: 2.7 +/- 1.5 mm, P =.028). No changes were evident in systolic or diastolic DMI indices in all other segments. CONCLUSION: DMI with TEE is feasible during cardiac operation. During pericardial opening, longitudinal D decreases in the septum, but not in the inferior wall. DMI requires further evaluation in the assessment of ventricular function and the detection of ischemia in the operating room.     

Acute regional myocardial ischemia identified by 2-dimensional multiregion tissue Doppler imaging technique.

BACKGROUND AND OBJECTIVE: Tissue Doppler echocardiography (TDE) is a promising method for the assessment of regional myocardial function, but pulsed TDE does not provide quantitative data from multiple regions simultaneously. This feature is important for the objective assessment of regional differences in myocardial function. In the present study, we investigated a new off-line TDE method that provides quantitative pulsed velocity data from an unlimited number of regions selected within a 2-dimensional (2D) image. The goal of the study was to determine the ability of this new approach to quantify regional myocardial function during acute myocardial ischemia induced by balloon angioplasty. METHODS: Twenty-two patients undergoing angioplasty of the left anterior descending coronary artery (LAD) were studied. Left ventricular longitudinal wall motion was assessed by 2D TDE from the apical 4-chamber view before, during, and after angioplasty. Images were sampled at a rate of 69 +/- 15 frames/s, and the off-line analysis allowed simultaneous measurement of velocities in multiple myocardial segments. RESULTS: There were 3 major alterations in the systolic velocity pattern during LAD occlusion. Peak early systolic velocities along the apical septum were significantly reduced during LAD occlusion (2.8 +/- 1.2 cm/s to 0.6 +/- 1.7 cm/s, P <.001). Myocardial velocities in mid systole suggested paradoxical wall motion (1.0 +/- 1.2 cm/s to -0.8 +/- 0.9 cm/s, P <.001). When comparing the ischemic regions of the left ventricle with the nonischemic regions, each patient demonstrated lower myocardial systolic velocities in the ischemic region. Furthermore, during early diastole, the wall motion of the ischemic segments showed a postsystolic contraction pattern with velocities changing from -0.9 +/- 1.0 cm/s to 1.9 +/- 1.3 cm/s (P <.001). CONCLUSION: This new 2D TDE approach is able to quantify detailed myocardial velocity profiles from multiple regions simultaneously. Single-beat comparisons of ischemic and nonischemic regions might enhance the sensitivity for diagnosing ischemic heart disease. Reversed systolic wall motion during midsystole and marked positive velocity during early diastole might be new and important markers of myocardial wall ischemia.     

Acute changes in systolic and diastolic events during clinical coronary angioplasty: a comparison of regional velocity, strain rate, and strain measurement.

Ultrasound-derived natural strain rate and strain are new Doppler myocardial imaging (DMI) parameters, which can measure local deformation independently of overall heart motion and thus could better characterize local contractility than DMI velocities alone. This study was undertaken to evaluate the relative benefits of regional velocity, strain rate, and strain measurements in detecting the range of acute changes in regional myocardial function in the "at-risk" zone during coronary angioplasty. Sixty-one patients (aged 63 +/- 12, 18 women) with stable angina pectoris were studied before, at the end of, and during recovery from a 60-second percutaneous transluminal coronary angioplasty (PTCA) balloon occlusion. High frame rate (147 fps) color DMI regional velocity data were derived from basal posterior (parasternal view) and mid, apical septal (apical view) "at-risk" segments as well as from the corresponding segments in healthy subjects and analyzed offline for velocity (VEL), strain rate (SR), and strain (epsilon) measurements. Coronary occlusion resulted in the reduction in VEL(SYS), SR(SYS), and epsilon(SYS) values for both radial (RCA/CX occlusion) and longitudinal data (LAD occlusion) in all segments analyzed. Velocity parameters alone failed to distinguish between baseline and occlusive measurements in the "at-risk" segments with visually abnormal baseline function. SR(SYS) and epsilon(SYS) had a higher diagnostic accuracy (sensitivity 75%, 80% and specificity 80%, 82%, respectively) than VEL(SYS) velocity alone (sensitivity 68%, specificity 65%,) for identifying acute ischemia in either baseline normal and abnormal segments. DMI-derived indexes can identify and quantify the spectrum of acute systolic and diastolic ischemic changes induced during clinical PTCA. The quantitation of regional deformation rather than motion would appear to be more appropriate in detecting and quantifying acute ischemic changes in myocardial function, especially in segments with pre-existing abnormal function.     

Color Doppler identification of a pericardial effusion in the fetus.

The aim of the study was to determine whether color Doppler identifies abnormal fluid within the pericardial space of the fetal were referred for heart. Second- and third-trimester fetuses diagnostic ultrasound. The four-chamber view of the fetal heart was imaged with real-time ultrasonography and examined for the presence or absence of separation of the pericardium from the epicardium, which extended from the atrioventricular junction toward the apex of the ventricle. To examine the pericardial space, the color Doppler maximal velocity was set at low Nyquist limits (0.08-0.24 m/s). In each fetus the transducer was angled so that the axis of the interventricular septum was parallel or tangential to the ultrasound beam to optimize the color Doppler recording. The control group consisted of 50 fetuses (16-38 weeks of gestation) who did not demonstrate evidence of pericardial effusion when examined with real-time ultrasound. Second- and third-trimester fetuses were selected from our database who demonstrated a pericardial effusion identified with real-time ultrasound.Color Doppler signals were not identified within the pericardial space in the 50 control fetuses. Fetuses with a pericardial effusion identified with real-time ultrasound demonstrated color Doppler within the pericardial space which was opposite to the direction of blood entering and exiting the ventricles. Color Doppler enhanced the detection of a pericardial effusion in the second-trimester fetus when the axis of the heart was and third-parallel or tangential to the ultrasound beam, which is suboptimal for real-time imaging.Color Doppler provides a new method to identify a pericardial effusion in the fetus during the second and third trimesters of pregnancy and complements the real-time examination.     

实验性冠状动脉痉挛的组织多普勒成像研究

目的　以麦角新碱诱发实验兔的冠状动脉 (冠脉 )痉挛引起急性心肌缺血的组织多普勒研究。方法　应用组织多普勒成像脉冲技术检测 35只冠脉痉挛引起急性心肌缺血兔的左室心尖部和前壁基底段、中段和心尖段的心肌运动 ,测量收缩期、舒张早期和舒张晚期运动峰值速度及时间速度积分 ,并与痉挛前对照分析。结果　冠脉痉挛后心尖部及前壁中段、心尖段的收缩波、舒张早期波峰值速度及时间速度积分明显低于痉挛前(P<0 .0 1)。舒张晚期波及前壁基底段各测值两组相差不显著 (P>0 .0 5 )。结论　组织多普勒成像脉冲技术能够准确测定心肌局部收缩和舒张运动速度 ,对冠脉痉挛引起的心肌缺血检测提供一种定量的方法。     

组织多普勒超声评价急性心肌梗死患者的收缩后收缩

目的 评价急性心肌梗死患者和健康人在等容舒张期出现的收缩后收缩（PSS）现象及临床意义。方法 利用组织多普勒超声检测36例急性心肌梗死患者和36例正常人的局部心肌，获得不同节段射血期、等容舒张期的峰值速度（VS、VIR）、应变率（SRS、SRIR）、应力（εS，εIRn）等。结果 正常组的生理性PSS多位于室间隔、前壁的基底、心尖段。梗死组的病理性PSS等容舒张期峰值速度增大，持续的时间延长。梗死组有92个节段VIR〉VS，结合应变率和应力分析，39个节段在等容舒张期主动收缩；12个节段为矛盾运动，其中8个节段是主动与被动活动的混合。结论 病理性和生理性PSS有明显差别。利用组织多普勒超声各项指标，有助于理解病理性PSS的机制，并指导临床的诊断、治疗。     

Assessment of myocardial velocities in healthy children using tissue Doppler imaging

The objective was to determine the normal range of tissue velocities in paediatric hearts as measured by tissue Doppler imaging. A prospective study was carried out involving 160 healthy children (mean age 10.8 y, range 4.0-17.9 y). Using tissue Doppler imaging (TDI) from parasternal long axis and apical views, peak velocities and peak myocardial velocity differences across the right ventricular anterior wall, interventricular septum and left ventricular posterior wall were assessed during systole, early and late diastole. The existence of transmyocardial velocity differences between the left and right side of the interventricular septum, as well as between the endocardium and epicardium of the left ventricular posterior wall was observed throughout the heart cycle. With range-gated TDI from apical four-chamber view, peak velocities were measured within the basal, mid and apical parts of the interventricular septum, and the left and right free ventricular walls. The highest peak systolic, early and late diastolic velocities were measured within the basal parts of all myocardial walls. The ranges of the calculated velocity ratios (early-to-late diastolic velocity and early diastolic-to-systolic velocity) for the various wall parts appeared to be overlapping. The correlations of peak myocardial tissue velocities and their ratios with age and weight were weak and practically irrelevant. These normal values of peak myocardial velocities, transmyocardial velocity differences and the ratios of peak wall velocities can be used as reference values in future investigations of ventricular dysfunction in this age group.     

定量组织多普勒技术对犬急性缺血心肌等容期运动特征的实验研究

目的探讨左室节段心肌在等容收缩期(IVC)与等容舒张期(IVR)长轴方向的运动特征及急性缺血时的变化规律.方法应用新的高帧频定量组织多普勒技术,对15只开胸犬分别在冠脉左前降支(LAD)结扎前后采集心尖长轴切面动态图,后处理分析前间隔与左室后壁各节段心肌在基础状态下及LAD结扎后15 min与60 min的速度曲线、应变率曲线及位移曲线在等容期的特征与变化规律,测量等容期的心肌运动速度(VIVC、VIVR)与应变率峰值(SRIVC、SRIVR)并进行比较.结果正常心肌在IVC表现短暂高速的收缩缩短运动(心尖长轴测值VIVC为正而SRIVC为负),IVR表现低速舒张伸长运动(VIVR为负值而SRIVR为正);急性缺血心肌IVC运动速度显著降低甚至转为负值,IVR表现反常的高速收缩缩短运动.缺血节段心肌VIVC、VIVR、SRIVC及SRIVR与基础状态比较均存在显著差异.结论心肌在短暂的等容时相内存在有规律的运动,且急性缺血时运动形式显著改变.用应高帧频的组织多普勒技术可以捕捉该时相的心肌运动信息并分析其特征,有助于增进对正常与缺血心肌功能状态的了解.     

Development of a fully quantitative approach to the interpretation of stress echocardiography using radial and longitudinal myocardial velocities.

BACKGROUND: Tissue Doppler may be used to quantify regional left ventricular function but is limited by segmental variation of longitudinal velocity from base to apex and free to septal walls. We sought to overcome this by developing a composite of longitudinal and radial velocities. METHODS AND RESULTS: We examined 82 unselected patients undergoing a standard dobutamine echocardiogram. Longitudinal velocity was obtained in the basal and mid segments of each wall using tissue Doppler in the apical views. Radial velocities were derived in the same segments using an automated border detection system and centerline method with regional chords grouped according to segment location and temporally averaged. In 25 patients at low probability of coronary disease, the pattern of regional variation in longitudinal velocity (higher in the septum) was the opposite of radial velocity (higher in the free wall) and the combination was homogeneous. In 57 patients undergoing angiography, velocity in abnormal segments was less than normal segments using longitudinal (6.0 +/- 3.6 vs 9.0 +/- 2.2 cm/s, P =.01) and radial velocity (6.0 +/- 4.0 vs 8.0 +/- 3.9 cm/s, P =.02). However, the composite velocity permitted better separation of abnormal and normal segments (13.3 +/- 5.6 vs 17.5 +/- 4.2 cm/s, P =.001). There was no significant difference between the accuracy of this quantitative approach and expert visual wall motion analysis (81% vs 84%, P =.56). CONCLUSION: Regional variation of uni-dimensional myocardial velocities necessitates site-specific normal ranges, probably because of different fiber directions. Combined analysis of longitudinal and radial velocities allows the derivation of a composite velocity, which is homogeneous in all segments and may allow better separation of normal and abnormal myocardium.     

速度向量成像评价正常成人右心室应变和应变率

目的 应用速度向量成像定量分析正常成人右室心肌应变和应变率.方法 选取健康成人32例,在心尖四腔观测量右室游离壁和室间隔右室面基底段、中间段、心尖段6个节段的应变和应变率收缩期峰值,Simpson法测量右室容量及射血分数.结果 Simpson法及速度向量成像法测量的正常右室射血分数高度相关(r=0.91,P＜0.01),右室游离壁基底段和中间段的应变、应变率均高于心尖段(P＜0.05).二者的应变和应变率差异均无统计学意义(P＞0.05),室间隔右室面的应变和应变率也有相同的规律,右室游离壁基底段和中间段的应变和应变率高于相应室间隔节段(P＜0.05),右室游离壁心尖段和室间隔心尖段的应变和应变率无明显差异,右室的应变和应变率和年龄无明显的相关性.结论 速度向量成像技术可以准确定量评估右室室壁应变和应变率.     

Myocardial longitudinal motion by tissue velocity imaging in the evaluation of patients with myocardial infarction.

Left ventricular (LV) longitudinal shortening plays an important role in cardiac contraction and is invariably affected by the presence of coronary artery disease. Third-generation tissue velocity imaging (TVI) color-maps cardiac movement by obtaining mean velocities of LV segments from the same set of beats. The goals of this study were to characterize patterns of longitudinal myocardial motion velocity in healthy subjects and to use these patterns to evaluate abnormal segments of patients with myocardial infarction (MI). Included were 20 healthy subjects and 16 patients with MI who underwent a 2-dimensional Doppler echocardiography study. Myocardial velocity profiles were taken at the anulus, basal, mid, and apical segments of the septal and lateral walls in the apical view. Segmental velocity patterns from healthy subjects were compared with abnormal segments in patients with MI. Both lateral and septal walls of healthy subjects showed significant basal-apical myocardial velocity reductions in systolic shortening (Sm) and early and late diastolic lengthening (Em and Am) and a basal-apical increase in the Em/Am ratio. The lateral wall had greater Sm and Em velocities than the septal wall. The Sm and Em velocities and the Em/Am ratio were significantly reduced in the abnormal segments in patients with MI. Latent lateral wall ischemia may have been detected in 5 of 9 patients with septal infarction, showing reduced Sm velocity in apparently normal lateral walls. In conclusion, TVI objectively quantifies directional and incremental changes in myocardial movement that are useful in evaluating global and regional myocardial function, and it may play a role in the detection of early myocardial ischemia.     

Tissue doppler imaging of left and right ventricles in normal children

Tissue Doppler imaging is a new ultrasound technology that derives measurements of contraction and relaxation velocities directly from the myocardium. However, data on myocardial velocities by using tissue Doppler imaging have not been established in normal children. In 48 normal children, myocardial velocities were measured using tissue Doppler imaging at three different sites (base, middle, and apex) in the left and right ventricles and the interventricular septum. In the left ventricular wall, the peak myocardial velocities during early diastole (peak E), during atrial contraction (peak A), and during systole (peak S) waves decreased gradually between the base and apical sites, whereas the ratio of E to A waves (peak E/A wave ratio) did not change among the 3 segments. Similar findings were obtained from the myocardial velocities in the right ventricle and the interventricular septum. A systolic and diastolic velocity gradient was also observed between the different ventricular walls. Significant correlations of the tissue Doppler parameters with age or heart rate were observed. In the left ventricle, the peak E wave demonstrated a stronger relation with age (r=0.77) than with heart rate (r=-0.65). The peak A wave did not change with age but correlated with heart rate. The peak E/A wave ratio showed a weaker relation with age (r=0.54) than with heart rate (r=0.62). The peak S wave was related to age (r=0.65) and to a lesser extent to heart rate (r= -0.51). Similar relationships of tissue Doppler parameters with age or heart rate were observed for the right ventricle and interventricular septum. The heterogeneous pattern and age- and heart-rate-related changes in normal myocardium demonstrated in this study must be taken into account when attempting to identify altered regional myocardial function with tissue Doppler echocardiography.     

Influence of different dynamic sporting disciplines on right ventricular Structure and function in elite male athletes

Our objective was to assess the influence of different levels of exposure to dynamic training on right ventricular (RV) structure, function and mechanics in elite male athletes. We recruited 492 male elite athletes aged between 18 and 30 years old. Athletes were grouped according to their sporting discipline using the Mitchell Classification as Low Dynamic (LD), Moderate Dynamic (MD) or High Dynamic (HD). All participants underwent 2D, Doppler, tissue Doppler and strain (ε) echocardiography with a focused and comprehensive assessment of the right heart. Athletes involved in MD sports had the largest absolute RV chamber size and when scaled to body size RVOT PLAX, RVOT2, RVD1 and RVD3 were larger in HD compared to MD and LD athletes. There were no between group differences in conventional RV functional indices as well as global RV ε (LD: ??23.4?±?3.1 vs. MD: ??22.7?±?2.7 vs. HD: ??23.5?±?2.6, %) and strain rate (P?>?0.01). The base to apex ε gradient in the RV septum was lower in the MD athletes compared to HD and LD due to a lower apical septal ε which significantly correlated with absolute RV chamber size. After scaling for body size there was evidence of larger RV cavities in both MD and HD athletes compared to LD athletes. Global RV function, ε and strain rate were not different between groups. MD athletes had lower apical septal ε that contributed to a smaller base-to-apex ε gradient that is partially associated with larger absolute RV chamber dimensions.     

右心室心尖不同部位起搏时左心室收缩时序的超声研究

目的探讨右心室心尖不同部位起搏时左心节段性室壁的收缩特征及时序。方法利用实时三维超声心动图技术确定右心室心尖起搏电极顶端在右心室心尖部的准确空间附着位点。运用应变显像技术，测定左心室壁各节段收缩期应力的达峰时间，即自心电图Q波起点至收缩期峰值应变时限（interval between Q wave of surface ECG and peak strain，QPSI），反映左心室各室壁的收缩时序；并计算QPSI的离散度，即最大QPSI减去最小QPSI的时限差，代表左心室内收缩延迟时间。观察正常对照组、右心室心尖不同部位起搏组左心室壁的节段性运动，评价各组左心室壁的收缩（或应变）时序及收缩协调性。结果右心室心尖起搏组的左心室壁收缩时序较正常对照组发生改变。右心室心尖侧壁起搏与右心室心尖间隔起搏组的左心室壁收缩时序不同，左室间隔心尖段、后壁基底段差异存在统计学意义（P〈0．05）。右心室心尖起搏时左室壁整体的收缩发生延迟，并且右心室心尖侧壁起搏组左室壁的收缩延迟时间明显大于右心室心尖间隔起搏组（P〈0．05）。结论右心室心尖不同部位起搏可以导致左心室不同的收缩模式改变，提示右心室心尖不同部位起搏所引起的电激动顺序及对心脏血流动力学的影响也存在差异。     

速度向量成像技术评价正常人心室节段功能

目的 应用速度向量成像技术研究正常人心肌运动速度、应变、应变率的正常值范围、变化规律，探讨其临床应用价值。方法采用Siemens Sequoia 512超声诊断仪及速度向量成像技术对35例健康志愿者心室各节段心肌收缩期径向和纵向速度、应变、应变率进行定量分析。结果 左右心室各室壁基底段、中间段和心尖段收缩期纵向峰值速度依次递减，基底段的速度最大，心尖段的速度最小；收缩期纵向应变、应变率在基底段、中间段、心尖段差异无统计学意义。左室各室壁二尖瓣水平、乳头肌水平、近心尖部水平收缩期径向峰值速度、应变、应变率差异无统计学意义；收缩期纵向平均峰值速度、应变、应变率较径向大，差异有统计学意义。右室游离壁的收缩期峰值速度和应变率高于后间隔右室面、后间隔左室面、左室侧壁，而应变差异无统计学意义。结论 速度向量成像技术能够定量评价节段性室壁功能，为临床评价左心室功能提供了又一有效方法。     

Simple detection of occluded coronary artery using retrograde flow in septal branch and left anterior descending coronary artery by transthoracic Doppler echocardiography at rest.

BACKGROUND: We hypothesized that coronary flow assessment by transthoracic Doppler echocardiography (TTDE) for both intramyocardial collateral channel and epicardial channels would be useful for identifying occluded left anterior descending coronary artery (LAD). METHODS: We assessed flow direction in the LAD and the septal branch (SEP) by TTDE in 302 consecutive patients who were suggested to have ischemic heart disease. We defined antegrade LAD flow as a direction from the base to the apex of the left ventricle in the anterior groove area, and antegrade SEP flow as a direction from anterior to inferior in the anterior interventricular septum. By contrast, we defined retrograde LAD and SEP flow as an inverse direction. We performed angiography on all patients. RESULTS: Retrograde flow was detected in 22 (LAD, 16 patients; SEP, 6 patients) of 23 patients with occluded LAD, and antegrade flow was detected in all patients without occluded LAD. The sensitivity and specificity for identification of occluded LAD by TTDE were 96% and 100%, respectively. CONCLUSIONS: Assessment of flow direction in both LAD and SEP by TTDE is a useful method in identification of occluded LAD.     

Use of strain imaging in detecting segmental dysfunction in patients with hypertrophic cardiomyopathy.

BACKGROUND: The distribution and magnitude of left ventricular hypertrophy are not uniform in patients with hypertrophic cardiomyopathy (HCM). Previous echocardiographic studies have focused on global left ventricular function. Recently, myocardial Doppler strain (epsilon) imaging, a newly developed technique, has allowed the quantification of regional myocardial motion. The aim of this study was to characterize regional left ventricular systolic function by myocardial Doppler epsilon imaging in patients with HCM. METHODS: Included in this study were 31 patients with asymmetric septal hypertrophy and HCM, and 41 age-matched healthy patients. Regional longitudinal axial systolic epsilon was assessed at the basal, mid, and apical segments of the septal and lateral walls and compared between both groups. RESULTS: Patients with HCM had reduced epsilon at the ventricular septum (-10.3 +/- 5.7%) compared with control patients (-19.4 +/- 3.3%, P <.001). In the HCM group, epsilon in the midseptum (-1.3 +/- 8.2%) was significantly less than at the basal (-12.2 +/- 8.7%, P <.01) and apical septum (-17.3 +/- 10.4%, P <.01), and was also less than at the midlateral wall (-9.4 +/- 5.3%, P <.05). There was a significant correlation between midseptal epsilon and intraventricular septum to posterior wall thickness ratio (r = 0.81, P <.001). CONCLUSION: Midseptal longitudinal epsilon was markedly decreased, even reversed in patients with HCM (paradoxic longitudinal systolic expansion), which was directly related to the degree of septal hypertrophy. Myocardial Doppler epsilon imaging could offer a unique approach to quantify regional systolic dysfunction in these patients.     

组织多普勒成像对冠状动脉痉挛引超急性心肌梗塞室壁运动频谱的研究

目的：应用组织多普勒成像对冠状动态（冠脉）痉挛引起急性心肌梗塞检测的临床应用价值。方法：应用组织多普勒成像脉冲技术检测20例冠脉痉挛引起急性心肌梗塞患者左室心尖部和前壁基底段、中段和心尖段的心肌运动,测量收缩期、舒张早期和舒张晚期运动峰值主时间速度积分并与19例健康成人对照分析。结果：冠脉痉挛梗塞组心尖部及前壁中段、心尖段的收缩波、舒张早期波峰值速度及时间速度积分明显低于对照组（P＜0．01）。舒张晚期波及前壁基底段各测值两组相差不显著（P＞0．05）。结论：组织多普勒成像脉冲技术能够准确测定心肌局部收缩和舒张运动速度,对冠脉痉挛引起急性心肌梗塞检测提供一种定量的方法。     

Strain rate acceleration yields a better index for evaluating left ventricular contractile function as compared with tissue velocity acceleration during isovolumic contraction time: an in vivo study

OBJECTIVE: Our study aimed to investigate whether strain rate acceleration (SRA) during isovolumic contraction time (IVCT) could serve as a sensitive indicator of myocardial function. METHODS: A total of 8 sheep underwent occlusion of left anterior descending coronary artery or diagonal branches and 2 sheep underwent left circumflex coronary artery occlusion to create septal, apical, or basal segment myocardial ischemia 19 to 27 weeks before the study. Baseline, volume-loading, dobutamine, and metoprolol infusion were used to produce 4 hemodynamic stages for each sheep. Doppler tissue imaging was acquired using a 5-MHz probe (GE/VingMed Vivid Five, GE Medical Systems, Milwaukee, Wis) on open-chest animals using the liver as a standoff at the apex. Using software (EchoPac, GE Medical Systems), SRA during IVCT was calculated and compared with tissue velocity acceleration (TVA) during IVCT from areas located in the normal and ischemic zones. Also, invasively monitored left ventricle dP/dt was measured as reference contractile function. RESULTS: Both TVA and SRA during IVCT showed higher values for normal tissue than for ischemic area (P <.0001). SRA for normal wall segments changed significantly during the 4 stages (P =.01) with corresponding changes on high-fidelity left ventricular pressure catheters (r = 0.92). TVA over normal segments showed no significant change (P =.29) in the 4 hemodynamic stages. Both TVA and SRA of the ischemic segments showed no significant change with pharmacologic maneuvers or loading conditions. CONCLUSIONS: SRA and TVA during IVCT are both useful indicators for detecting abnormal heart wall motion. However, SRA tends to be more sensitive than TVA for differentiating the response to stress conditions.     

速度向量成像技术在诊断冠心病心肌缺血中的应用价值

目的 探讨速度向量成像（VVI）技术在诊断冠心病心肌缺血中的应用价值.方法 正常对照组与冠心病组各30例,应用VVI技术检测两组左室侧壁、前壁、室间隔及下壁基底、中间段、心尖节段的收缩期峰值速度（Vs）、舒张期峰值速度（Ve）、应变（ε）及应变率（εR）,结果进行对比分析.结果 正常对照组左室壁各节段心肌运动的Vs和Ve均由基底部向心尖部递减;左心室各节段心肌的ε和εR之间比较差异无统计学意义（P 〉 0.05）.冠心病缺血节段Ve、ε及εR均较正常对照组显著降低,差异有统计学意义（P 〈 0.01）,部分节段Vs显著降低,差异有统计学意义（P 〈 0.05）.结论 VVI技术能定量检测局部心肌的运动情况,有助于临床诊断心肌缺血.