The quantification of dipyridamole induced changes in regional deformation in normal, stunned or infarcted myocardium as measured by strain and strain rate: an experimental study

Strain rate imaging (SRI) during dobutamine stress-echocardiography (DSE) has been shown to differentiate between ischemic substrates based on the segmental response. Dipyridamole stress echo (DIPSE) is currently used as an alternative to DSE in detecting coronary artery disease. The aim of this study was: (a) to determine the normal response in peak-systolic myocardial strain (S) and strain-rate (SR) during DIPSE and (b) to compare the S and SR responses of DSE and DIPSE in the same chronically ischemic/infarcted segments in the setting of single vessel disease. Methods The deformation response to DIPSE was studied in 7 normal pigs and in an additional 18 pigs, with a spectrum of ischemic substrates. S and SR data were extracted from a posterior wall “at risk” segment at baseline and during both DSE and DIPSE. The animals were divided into different ischemic substrate (stunning, non-transmural and transmural infarction), based on the DSE response as previously suggested. Results In normal myocardium, dipyridamole induced no changes in regional systolic deformation neither during nor after the infusion. Furthermore there was no detectable response in S and SR in segments with either a non-transmural or a transmural infarction. However, in myocardial segments with a DSE “stunning response”, both end systolic S and peak-systolic SR tended to “normalize” at peak dipyridamole dose. Conclusions These results suggest that dipyridamole does not induce changes in regional deformation in normal or (partially) infarcted myocardium. Only in stunned myocardium (in the setting of single-vessel disease), dipyridamole tends to normalize deformation.     

应变显像舒张指数评价急性心肌梗死患者经皮冠状动脉介入治疗术后左心室舒张功能延迟恢复

目的 应用二维超声斑点追踪显像(STI)技术检测急性心肌梗死(AMI)患者经皮冠状动脉介入治疗术(PCI)后不同时期的左心室心肌应变指标的变化,探讨应变显像舒张指数(SI-DI)对定量评价再灌注后局部心肌舒张功能延迟恢复的临床应用价值。方法 选择40例AMI患者,分别在PCI术前、术后1天、7天及1个月接受超声心动图检查,应用二维应变显像技术测定缺血心肌及非缺血心肌的横向应变峰值(Speak)、应变峰值延迟时间(TPS)及SI-DI,并进行比较。结果 冠状动脉的急性闭塞会引起相应灌注区域心肌收缩及舒张功能的显著降低,与非缺血心肌相比较,缺血心肌的Speak显著降低,TPS明显延长,SI-DI显著降低(P均<0.05)。PCI治疗7天及1个月后,与术前比较,缺血心肌的Speak明显升高,TPS明显缩短,SI-DI明显升高(P均<0.05)。代表收缩功能的Speak和TPS两项参数在术后7天恢复至正常,而代表舒张功能的SI-DI在术后1个月恢复至正常。非缺血心肌的各项参数在各时期的改变无明显差异(P均>0.05)。结论 SI-DI可用于评价AMI患者PCI术后左心室局部心肌舒张功能的延迟恢复情况。     

Quantification of regional left and right ventricular radial and longitudinal function in healthy children using ultrasound-based strain rate and strain imaging.

BACKGROUND: Noninvasive assessment of left (LV) and right (RV) ventricular function in children could benefit from a technique that would characterize local myocardial deformation. Color Doppler myocardial imaging (CDMI) allows the calculation of either local longitudinal or radial Strain Rate (SR) and Strain (epsilon). To determine the clinical feasibility and reproducibility of longitudinal and radial SR and epsilon, the following study was carried out. METHODS: CDMI data were obtained from 33 healthy children (4-16 years). To quantify regional longitudinal and radial function SR and epsilon data were obtained from apical and parasternal views respectively. From the extracted SR curves, peak values for systole, early diastole, and late diastole were calculated. From the extracted epsilon curves the systolic, early and late diastolic epsilon values were calculated. RESULTS: LV longitudinal deformation were homogeneous for LV basal, mid and apical segments (peak systolic SR: -1.9 +/- 0.7 s(-1), systolic epsilon -25% +/- 7%). Longitudinal SR and epsilon values were significantly higher and heterogeneous in the RV (compared with LV walls) and were maximal in the mid part of the RV free wall (peak systolic SR: -2.8 +/- 0.7 s(-1), systolic epsilon -45% +/- 13%). The RV inferior wall showed homogeneous but lower longitudinal SR and epsilon values. The LV systolic and diastolic SR and epsilon values were higher for deformation in the radial direction compared with the longitudinal direction (radial peak systolic SR: 3.7 +/- 0.9 s(-1), radial systolic epsilon 57% +/- 11%; P <.0001). The interobserver variability for radial systolic epsilon and SR was 10.3% and 13.1%, respectively. CONCLUSION: Ultrasound-based Strain SR/epsilon imaging is a practical, reproducible clinical technique, which allows the calculation of regional longitudinal and radial deformation from both LV and RV segments. The combination of regional SR/epsilon indices and the timing of specific systolic or diastolic regional events may offer a new noninvasive approach to quantifying regional myocardial function in congenital and acquired heart disease in children.     

应变率成像技术对冠状动脉粥样硬化性心脏病患者左室局部舒张功能异常的评估

背景:局部心肌舒张功能异常是心肌缺血、梗死的早期和特征性表现.应变率成像是一种新型超声成像技术,具有良好的时间和空间分辨率,可用于定量分析局部心肌功能.目的:应用应变率成像技术定量分析并比较心绞痛与心肌梗死患者左室缺血及梗死心肌舒张期应变率变化,探讨其评价冠状动脉粥样硬化性心脏病(简称冠心病)患者左室局部舒张功能异常的价值.设计:病例对照研究.单位:中山大学附属第二医院心血管内科.对象:选取2005-10/2006-04中山大学附属第二医院门诊和住院患者作为研究对象,其中冠心病心绞痛组11例、心肌梗死组21例,对照组20例.方法:常规超声检查后,取心尖四腔、二腔及左室长轴观,应用二维彩色组织多普勒速度模式记录左室侧壁、后间隔、下壁、前壁、后壁及前间隔的运动图像,并存入磁光盘.利用QLAB4.2分析软件进行脱机分析,获取SR曲线.主要观察指标:分析心绞痛组缺血心肌、心肌梗死组梗死心肌和对照组左室心肌节段.分别测量舒张早期峰值应变率(SRe)和舒张晚期峰值应变率(SRa).结果:缺血、梗死心肌的SRe和SRa均显著低于正常心肌(P＜0.05);梗死心肌与缺血心肌相比,SRe及SRa均无显著性差异(P＞0.05).结论:应变率成像测得SRe和SRa可反映冠心病患者左室局部心肌舒张功能异常,但对于缺血与梗死心肌的鉴别诊断价值有限.     

Incidence and characteristics of segmental postsystolic longitudinal shortening in normal, acutely ischemic, and scarred myocardium.

OBJECTIVE: Myocardial longitudinal shortening after aortic valve closure (postsystolic shortening [PSS]) is considered a marker of pathology with diagnostic potential. However, PSS can also occur in healthy subjects. We, therefore, investigated the occurrence and characteristics of PSS in control subjects and patients, and how to distinguish normality from disease. METHODS: In 20 young control subjects, 10 older control subjects, 30 patients with acute myocardial infarction (acute ischemia), and 10 patients with postischemic myocardial scar, longitudinal myocardial deformation was measured with Doppler tissue strain rate (SR) imaging. Segmental SR and strain were visually and quantitatively analyzed and compared. RESULTS: In young control subjects, PSS was found in 98 of 313 segments (31%) and showed gaussian distribution (median 1.3%). During ejection time, median peak SR was -1.4 s(-1) and median strain -16.6%. In older control subjects, parameters differed only slightly. In acutely ischemic and scarred myocardium, both systolic strain and SR were significantly reduced or inverted. In disease, PSS occurred significantly more often (78% and 79%, respectively), was significantly higher in magnitude, and its peak occurred later than in young and older control subjects. CONCLUSION: PSS is a normal finding in healthy subjects occurring in approximately one-third of myocardial segments and, thus, is not always a marker of disease. Our data indicate that pathologic PSS can be detected by coexisting reduction in systolic strain and, second, by exceeding a postsystolic strain magnitude cutoff.     

应变率成像定量评价冠心病局部心肌舒缩功能

目的 观察冠心病缺血心肌应变率（SR）变化特点，探讨应变率成像（SRI）技术定量评价冠心病局部心肌功能的应用价值。方法 应用SRI对48例冠心病患者和42例正常人左室前间隔与后壁各室壁节段纵向收缩期、快速充盈期及房缩期的SR参数进行测定，并以冠脉造影结果为标准进行对比分析。结果 在收缩期和快速充盈期，冠心病缺血节段的彩色M-型SRI常表现为SRI色带变浅、消失，甚至显示为反相色彩，表明缺血心肌收缩期和快速充盈期SR减低、消失，或者呈现矛盾运动。缺血心肌收缩期和快速充盈期的径向、纵向SR测值均较对照组相应节段明显减低。冠心病组缺血节段和对照组相应节段的SRA基本无明显差异。结论 冠心病缺血心肌收缩期和快速充盈期的SR明显减低、消失，甚至倒置。SRI技术是临床无创、定量评价冠心病局部心肌功能的新方法。     

应变率成像评价冠心病冠状动脉左前降支供血区心肌形变力及非同步性

目的应用应变率成像(SRI)技术对冠心病患者左室局部心肌形变能力及非同步性进行检测,探讨其在冠心病诊断中的应用价值。方法采用SRI技术对30例冠心病患者和30例正常人的冠状动脉左前降支供血心肌进行检测,测量收缩期应变率(SRs)及QRS波起始至SRs峰值的时限(Ts)、等容舒张期应变率(SRIVR)及QRS波起始至SRIVR峰值的时限(TIVR)。结果病例组左前降支供血的各相关心肌节段SRs明显降低,Ts明显延迟;病例组表现为负向等容舒张期应变率的节段数明显增多,其峰值明显高尖,TIVR时限延迟。结论SRI是一种无创性定量评价局部心肌形变能力及非同步性的新方法,对早期判断冠心病患者左室心肌收缩和舒张功能异常有重要价值。     

应变率成像对冠状动脉搭桥前后左心室形变及同步性的评价

目的 采用应变率成像(SRI)定量评价冠状动脉搭桥(CABG)前、后左室局部心肌收缩形变及同步性的变化,判断手术疗效,预测再狭窄.方法 60例冠心病患者(病例组)分别于CABG术前1 d、术后10 d、1个月,3个月及6个月测量左前降支参与供血的室壁节段的收缩期应变率(SRsys)和应变(Ssys),计算收缩后应变指数(PSI).40例健康志愿者作为对照组.比较术前与对照组及CABG术前、术后各时间点间SRsys、Ssys和PSI的变化情况.结果 病例组SRsys和Ssys值较对照组显著减低.52例患者CABG术后1个月开始搭桥节段SRsys和Ssys逐渐增大,多数节段术后3个月和6个月时差异有统计学意义.病例组术前PSI较对照组明显增高,术后6个月,所有节段PSI值均明显回缩.超声检出8例患者发生术后再狭窄,其阳性预测值为75%.SRI参数法诊断室壁运动异常的敏感性高于传统的二维超声目测法,Ssys的敏感性高于SRsys.结论 SRI可定量评价左室壁局部收缩形变及同步性,动态观察CABG手术前、后局部心肌功能的变化,判定术后疗效,发现术后再狭窄.     

应变率显像定量评价冠状动脉旁路移植术后左心室局部功能

目的 探讨应变率显像(SRI)技术在评价冠心病患者冠状动脉旁路移植术前后左心室局部功能变化中的应用价值.方法 对16例冠心病患者分别于冠状动脉旁路移植术前3 d、术后12 d及3个月行超声心动图检查,应用SRI技术对左室各壁基底段和中间段的局部心肌功能进行定量分析,共分析192个节段.根据术前二维超声心动图室壁运动情况将心肌节段分为运动正常组(152个节段)和运动异常组(40个节段).结果 术前运动正常组收缩期心肌峰值应变率(SRs)和舒张早期心肌峰值应变率(SRe)与运动异常组相比差异无统计学意义(P>0.05).运动异常组术后3个月的房缩期心肌峰值应变率(SRa)较术前3 d增高(P<0.05).运动正常组术后3个月与术前3 d相比,SRs、SRa及SRe均增高(分别P<0.05和0.01),术后3个月与术后12 d相比,SRs增高(P<0.05).结论 应用SRI技术能定量评价冠状动脉旁路移植术前后左室局部心肌功能的改变.     

超声组织追踪和应变率显像技术评价冠心病左室收缩功能

目的探讨超声组织追踪成像(TTI)和应变率成像(SRI)评价冠心病患者左室收缩功能的临床价值,比较TTI和SRI两种方法评价左室收缩功能敏感性的差异.方法A组22例健康人群,B组20例左前降支和18例右冠状动脉狭窄的冠心病患者,应用组织速度成像(TVI)技术于心尖四腔切面、心尖两腔切面、心尖左室长轴切面上显示后间隔、下壁、前壁及前间隔的图像,并应用TTI及SRI定量测量并分析左室11个节段收缩期峰值位移值及收缩期最大应变率.结果B组各节段的各项指标较A组明显减低.冠心病组总节段数为208个,TTI、SRI检出异常节段数分别为141、126个,检出比例分别为67.79%、60.58%.结论TTI和SRI技术能准确地定量评价冠心病患者的左室收缩功能,对左室收缩功能评价TTI与SRI结果之间无明显统计学差异.     

应变及应变率成像评估心肌桥患者局部心肌缺血的价值

目的探讨定量组织速度成像和应变及应变率评估冠状动脉心肌桥引起局部心肌缺血的临床价值。方法冠状动脉前降支心肌桥患者47例(心肌桥组)与冠状动脉正常者40例(对照组),测量前降支支配区域9个节段的收缩期峰值速度、峰值应变及应变率、舒张早、晚期峰值速度、舒张早、晚期峰值应变及相应的应变率。结果与对照组比较,心肌桥组前间隔各节段、前壁基底段及中间段、后间隔中间段收缩期峰值速度及峰值应变率明显减低(P<0.05);前间隔基底段和中间段舒张早期、晚期峰值速度及舒张早期峰值应变率明显减低(P<0.05);前壁基底段、前间隔各节段收缩期峰值应变,前壁、前间隔舒张晚期峰值应变明显减低、侧壁心尖段明显升高(P<0.05)。结论定量组织速度成像和应变及应变率可定量检测冠状动脉心肌桥引起的心肌缺血。     

冠心病患者冠状动脉支架置入术前后局部心肌应变率的定量分析

目的 探讨心肌应变率显像（SRI）技术在评价冠心病患者冠状动脉支架置入术前后局部室壁运动状态中的应用价值。方法应用SRI技术对38例冠心病患者冠状动脉支架置入术前后心尖四腔、两腔观各节段局部心肌功能进行定量分析。结果术前缺血心肌应变率曲线中收缩期、舒张早期和舒张晚期SR峰值均小于正常节段并可出现收缩后收缩（PSS）波。术后经治疗的缺血心肌各峰值逐渐增加，PSS波消失，各指标较未经治疗的缺血心肌明显增加。结论SRI技术可准确识别缺血心肌节段，冠状动脉支架置入术可有效改善缺血心肌血供，提高心肌发生变形的能力。     

组织速度成像技术对冠心病左室壁收缩运动异常的评价

目的探讨组织速度成像(TVI)评价冠状动脉粥样硬化性心脏病(冠心病)患者左室壁收缩运动异常的临床意义,比较TVI中定量组织速度成像(QTVI)、应变率成像(SRI)、组织追踪成像(TTI)和组织同步成像(TSI)之间对于评价左室壁收缩运动异常的敏感性差异。方法对正常组健康人群及冠心病组的病例应用TVI采集心尖四腔切面、心尖两腔切面、心尖左室长轴切面的后间隔、下壁、前壁及前间隔图像,获得QTVI、TSI的速度-时间曲线图,TTI的位移-时间曲线图及SRI的应变率曲线图,测量左室11个节段收缩期的峰值速度(Vp)、峰值位移(D)及最大应变率(SR)并进行定量分析。结果以正常组各节段各项指标为标准,冠心病组各节段的各项指标较对照组明显减低。冠心病组共208个节段,QTVI、SRI、TTI、TSI对异常节段的检出比例分别为56.73%、60.58%、67.79%、50.48%。结论TVI技术能有效地定量评价冠心病的左室壁收缩运动异常,其中尤以TTI对评价左室壁收缩运动异常最为敏感。     

Evaluation of the longitudinal contraction of the left ventricle in normal subjects by Doppler tissue tracking and strain rate.

BACKGROUND: Tissue tracking (TT) and strain rate (SR) are new echocardiographic modalities on the basis of Doppler tissue imaging, which allow assessment of the systolic longitudinal contraction of the myocardium. OBJECTIVE: The aim of this study was to describe the global and regional longitudinal function of the left ventricle by TT and SR analysis. METHODS: The study population consisted of 55 normal subjects. To assess longitudinal myocardial contraction, TT was performed in the standard apical views and expressed as a score index of the 16 myocardial segments. In addition, SR was performed in each segment. RESULTS: The mean longitudinal contraction was 7.8 +/- 1.8 mm. Longitudinal contraction was significantly decreasing with increasing age and systolic blood pressure (r = -0.46, P <.01 for both measures), but independent of heart rate, left ventricular diameters, ejection fraction, and fractional shortening. SR was found significantly larger in the basal segments than in the middle and apical segments (-1.8 +/- 0.6 s(-1) vs 1.4 +/- 0.3 s(-1) P <.001). CONCLUSION: TT and SR analysis are easily obtained and may complement conventional measures of left ventricular systolic function.     

Quantification of regional left and right ventricular longitudinal function in 75 normal fetuses using ultrasound-based strain rate and strain imaging

Previous reports have demonstrated that myocardial velocities are not sufficiently sensitive in fetal heart studies. Strain (S) and strain rate (SR) imaging is a new noninvasive ultrasonic technique able to quantify regional myocardial deformation properties. SR imaging has a superior sensitivity than myocardial velocity for noninvasive assessment of ventricular function, but this technique has not been used in the fetal heart. Our aim was to evaluate the feasibility of S/SR imaging in the fetal heart and to study characteristics of myocardial deformation properties and their changes with the gestational age in healthy fetuses. We studied 75 normal fetuses (weeks gestation 25 +/- 4, no evidence of structural cardiovascular disease by 2-D echo and Doppler study) using S/SR imaging. Left (LV) and right ventricle (RV) peak myocardial systolic, early diastolic and SR values during atrial contraction were obtained but, for S, we measured only peak systolic values. The sample volume was placed in the mid-segment of LV septal, lateral and RV free wall. S and SR curves were obtained in all the studied population. Peak longitudinal systolic deformation was homogeneous in all the walls studied. Moreover, fetal myocardial S and SR during diastole were characterized by a higher deformation during atrial contraction than during early filling. Peak systolic and peak diastolic ratios of regional myocardial deformation properties significantly correlated with the gestational age. Inter- and intraobserver variabilities for S and SR parameters were < 15%, < 18% and < 13%, < 15%, respectively. SR imaging is feasible in selected healthy fetuses, with a limited reproducibility; we presented normal values for the fetal heart; S/SR during fetal life are homogeneous in both LV and RV; and longitudinal myocardial deformation properties increase with the gestational age.     

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.     

Assessment of regional longitudinal myocardial strain rate derived from doppler myocardial imaging indexes in normal and infarcted myocardium.

Myocardial deformation properties may be characterized by regional strain rates (SRs) calculated from Doppler myocardial velocity data. In 10 control subjects and 12 patients with established transmural infarcts, longitudinal median segmental SR, strain, and myocardial velocity were analyzed and compared with the corresponding wall motion score. All segments in control subjects and normal segments in infarct patients showed no significant difference in either systolic or diastolic SR (systolic: -1.27+/-0.39 s(-1) versus -1.23+/-0.24 s(-1), not significant [NS]; and isovolumic relaxation [IVR]: 1.23+/-0.38 s(-1) versus 1.95+/-0.62 s(-1), NS; respectively) and strain (-0.21+/-0.06 versus -0.19+/-0.06, NS). In infarcted segments, peak systolic SR, systolic strain, and early diastolic SR showed the most pronounced reduction (hypokinetic and akinetic) or even inversion (dyskinetic segments: 0.10+/-0.26 s(-1), 0.00+/-0.03, and -1.78+/-0.67 s(-1), respectively; P<.001). In this study, new myocardial deformation indexes were shown to quantitatively describe the function of normal and chronically infarcted regions.     

Optimisation of strain rate imaging for application to stress echocardiography

We sought to improve the feasibility of strain rate imaging (SRI) during dobutamine stress echocardiography (DSE) in 56 subjects at low risk of coronary disease. The impact of several SRI changes during acquisition were studied, including: (1) changing from fundamental to harmonic imaging; (2) parallel beamforming; (3) alteration of spatial resolution and (4) narrow sector acquisition. We assessed SR signal quality, a quantitative measure of signal noise and measurements of SRI. Of 1462 segments evaluated, 6% were uninterpretable at rest and 8% at peak stress. Signal quality was optimised by increasing temporal (p = 0.01) and spatial resolution (p < 0.0001 vs. baseline imaging) at rest and peak. Increasing spatial resolution also minimised signal noise (p < 0.0001). Inter-observer variability of time to peak SR and peak SR were less with high temporal and spatial resolution. SRI quality can be improved with harmonic imaging and higher temporal resolution but optimisation of spatial resolution is critical.     

应变率显像对糖尿病患者左室收缩功能的评价

目的探讨应变率显像(SRI)技术评价糖尿病患者左室收缩功能的临床价值。方法获取33例糖尿病患者和26例正常人心尖左心长轴、二腔和四腔切面应变率曲线,测量左室各节段心肌收缩期峰值应变率和二尖瓣环峰值应变率(SR)。用Simpson法测量左室射血分数(LVEF)。结果与正常组相比,糖尿病组左室各节段心肌的纵向SR均明显降低(P<0.05),瓣环的SR与LVEF呈正相关(r=0.619,P<0.05)。结论SRI为定量评价糖尿病患者左室整体和局部收缩功能提供了无创的新方法。     

Dobutamine induces ineffective work in regional ischaemic myocardium: an experimental strain rate imaging study

In the present study, we sought to investigate the effects of differing inotropic conditions on regional myocardial function in ischaemic segments. In an experimental pig model ( n =11), the regional deformation parameters peak systolic strain rate [SR(SYS) (peak velocity of thickening)], systolic strain [epsilon(SYS) (systolic wall thickening)] and post-systolic strain [epsilon(PST) (ongoing wall thickening after end of systole)] were measured during normal perfusion and regional ischaemia of the posterior wall. These parameters were compared with global contractility [E(ES) (end-systolic elastance)] measured by a conductance catheter. Ischaemia was induced by an active coronary hypoperfusion in the circumflex coronary artery. Measurements were done at baseline, during dobutamine and during esmolol infusion. In normal perfused hearts, SR(SYS) (4.8+/-0.2 s(-1) at baseline) increased during dobutamine infusion, decreased during esmolol infusion and correlated significantly with global E(ES). In addition, epsilon(SYS) averaged 93+/-3% at baseline and there was almost no epsilon(PST) (4+/-1%) in normal myocardium. In ischaemic myocardium, SR(SYS) and epsilon(SYS) were significantly reduced compared with normal myocardium at baseline (SR(SYS)=2.8+/-0.3 s(-1), and epsilon(SYS)=43+/-6%; P <0.001 compared with normal perfused hearts), whereas global E(ES) was unchanged. In contrast, epsilon(PST) was significantly increased in regional ischaemic segments compared with the non-ischaemic myocardium (15+/-2%; P <0.001). During the dobutamine infusion, SR(SYS) remained unchanged. In contrast, epsilon(SYS) decreased (25+/-5%; P <0.001) and epsilon(PST) increased (25+/-4%; P <0.05) significantly during dobutamine infusion in ischaemic myocardium. In ischaemic segments, an inotropic stimulation with dobutamine resulted in a shift of strain from systole (epsilon(SYS)) to post-systole (epsilon(PST)). Thus dobutamine induced ineffective myocardial work in ischaemic segments.