Ultrasonic tissue characterization with integrated backscatter during inotropic stimulation

Ultrasonic tissue characterization with integrated backscatter is an objective method to quantitatively define the physical state of the myocardium. To determine if backscatter imaging during inotropic stimulation could be used objectively to determine the myocardial viability and ischemia in patients with ischemic heart disease, the backscatter changes were examined in 23 patients with myocardial infarction during dobutamine stress two-dimensional (2-D) echocardiography. Coronary angiography was performed within 1 to 2 days after the stress test. The results of this study demonstrated that changes in backscatter variability correlated significantly with the wall motion changes in stress echocardiography during dobutamine infusion (p < 0.0001). In addition, it was shown that the backscatter changes were significantly different in various types of myocardial tissue. In 23 healthy control segments, the ultrasonic backscatter variability was preserved and unchanged during inotropic stimulation (p = NS). In 15 viable infarct zones, restoration or an increase in backscatter variability during low-dose dobutamine infusion was noted, this being lost when ischemia developing during high-dose dobutamine infusion (p < 0.01). In 9 nonviable infarct zones, the phase-weighted variation was usually ≤ 0 and did not change significantly during inotropic stimulation, regardless of the patency of the infarct-related arteries. In 15 remote ischemic myocardial zones, the backscatter variability was preserved at the baseline level, did not change during low-dose dobutamine infusion, but decreased significantly during high-dose dobutamine stress (p < 0.01). In conclusion, dobutamine stress tissue characterization could offer an objective approach for the detection of myocardial viability and ischemia, and might be a useful adjunct to the conventional stress echocardiography.     

Differentiation of left ventricular diastolic function by mid-diastolic mitral annular motion patterns

Mid-diastolic mitral annular motion may be driven by strain energy, an energy for myocardial recoil, stored during the previous systole. Hence, various patterns of mid-diastolic mitral annular motion may imply different left ventricular (LV) diastolic function. The purpose of this study is to compare LV diastolic properties among different types of mid-diastolic mitral annular motion. Two-hundred and three consecutive subjects underwent an echocardiographic examination at our outpatient clinic. Study subjects were classified into three groups according to mid-diastolic mitral annular motion patterns. Upward and downward La waves were defined, respectively, as a clear apically and atrially directed mid-diastolic annular motion on at least three consecutive beats with the average peak velocity ≥2 cm/s. Subjects with upward La wave, with downward but without upward La wave and without La wave were categorized as groups 1, 2 and 3, respectively. Early diastolic mitral annular velocity (Ea) was higher and the ratio of transmitral E wave velocity to Ea was lower in group 1 than in groups 2 and 3 (all p < 0.001). The diagnostic accuracy of upward La wave in prediction of normal diastolic function fell between 75% and 88%. In conclusion, patients with upward La wave had better LV diastolic function and lower LV filling pressure than patients without it. Upward La wave is useful in prediction of normal diastolic function. Therefore, analysis of mid-diastolic mitral annular motion may be complementary to other measures of LV diastolic function. (E-mail: wcvoon@giga.net.tw)     

Echocardiographic analysis of systolic and diastolic left ventricular wall motion during transient myocardial ischemia

Left ventricular (LV) wall motion (anterior and posterior) and simultaneous LV pressure were recorded during 30-second left anterior descending (LAD) or circumflex (CX) coronary artery occlusions in open-chest dogs to provide an echocardiographic model of the evolution of wall motion changes during myocardial ischemia. Prominent diastolic echocardiographic motion changes of progressive decrease in LV wall rapid-filling velocities (RFS), slow-filling velocities (SFS), and increased end-diastolic diameter were accompanied by a marked increase in initial and end-diastolic pressures (150% and 70%, respectively; all p < 0.05). Early (within ten seconds) and progressive decrease in rate (SES), amplitude (E), and duration (TTR) of systolic motion were noted with an increased systolic diameter (p < 0.05). Ischemic regions developed a characteristic pattern with early relaxation followed by a diastolic inward motion (DIM). These observations confirm and extend other investigators' findings on the motion of the ischemic myocardium and may be applicable to responses to transient myocardial ischemia noted in humans.     

Effect of an acute increase in afterload on left ventricular regional wall motion velocity in healthy subjects.

We recorded left ventricular (LV) wall motion velocities before and after angiotensin II infusion by pulsed tissue Doppler imaging in 20 healthy subjects, and evaluated the responses of systolic and diastolic LV function along the long and short axes during an acute increase in afterload. Angiotensin II was administered intravenously to obtain a 30% increase in mean blood pressure. After angiotensin II infusion, LV end-systolic dimension and end-systolic circumferential wall stress increased significantly, and the percentage of LV fractional shortening decreased significantly. Peak first systolic LV wall motion velocity (Sw1 ) along the long axis decreased markedly compared with that along the short axis, and peak second systolic LV wall motion velocity (Sw2 ) along the short axis decreased significantly compared with that along the long axis. Early diastolic LV wall motion velocities along both the long and short axes decreased significantly, whereas atrial systolic LV wall motion velocity did not change. In conclusion, an acute increase in afterload caused a significant decrease in longitudinal fiber shortening during the isovolumic contraction phase (Sw1 along the long axis), circumferential fiber shortening during the ejection phase (Sw2 along the short axis), and LV relaxation during early diastole (early diastolic LV wall motion velocities along both axes) in healthy subjects. Pulsed tissue Doppler imaging may be useful for detecting the effect of various loading conditions on LV wall motion velocities along the long and short axes.     

Normal regional right ventricular function and its change with age: a Doppler myocardial imaging study.

BACKGROUND: Doppler Myocardial Imaging (DMI) is a new technique currently being studied for the assessment of regional systolic and diastolic left ventricular (LV) function. No normal values or data on age-related changes in regional myocardial right ventricular (RV) velocities are available. METHODS AND RESULTS: Color DMI was used in 32 healthy volunteers (aged 16-76 years) to derive regional velocities from basal, medial, and apical segments of the RV free wall in the apical 4-chamber view, and from distal segments as well as from the tricuspid annulus in the parasternal long-axis view. Both mitral annular and regional LV velocities (4-chamber, long-axis parasternal view) were also recorded and compared with corresponding RV regional velocities. The M-mode displacement of the cardiac base was measured. Corresponding RV and LV DMI data sets were compared. For longitudinal function, RV free wall systolic velocities were consistently higher than velocities recorded in corresponding LV segments (analysis of variance, P <.05). Older subjects (40-76 years; 13 men, 2 women) had lower RV long-axis regional velocities than younger subjects (16-39 years; 15 men, 2 women), but had higher short-axis RV systolic velocities. For diastolic velocities, a negative correlation between age and the ratio of regional early diastolic to late diastolic velocity was shown for all RV free wall segments (eg, basal segment: r = -0.63, P <.0001). CONCLUSIONS: The right ventricle has higher long-axis regional velocities, a greater excursion of its lateral atrioventricular valve ring, and reduced circumferential shortening velocities compared with the left ventricle. Right ventricular longitudinal shortening is dominant over short-axis function in healthy young subjects. Normal age-related changes of diastolic velocities for each segment of the normal RV free wall have been defined.     

Mechanism of decreased sensitivity of dobutamine associated left ventricular wall motion analyses for appreciating inducible ischemia in older adults

Background

Dobutamine associated left ventricular (LV) wall motion analyses exhibit reduced sensitivity for detecting inducible ischemia in individuals with increased LV wall thickness. This study was performed to better understand the mechanism of this reduced sensitivity in the elderly who often manifest increased LV wall thickness and risk factors for coronary artery disease.

Methods

During dobutamine cardiovascular magnetic resonance (DCMR) stress testing, we assessed rate pressure product (RPP), aortic pulse wave velocity (PWV), LV myocardial oxygen demand (pressure volume area, PVA, mass, volumes, concentricity, and the presence of wall motion abnormalities (WMA) and first pass gadolinium enhanced perfusion defects (PDs) indicative of ischemia in 278 consecutively recruited individuals aged 69 ± 8 years with pre-existing or known risk factors for coronary artery disease. Each variable was assessed independently by personnel blinded to participant identifiers and analyses of other DCMR or hemodynamic variables.

Results

Participants were 80% white, 90% hypertensive, 43% diabetic and 55% men. With dobutamine, 60% of the participants who exhibited PDs had no inducible WMA. Among these participants, myocardial oxygen demand was lower than that observed in those who had both wall motion and perfusion abnormalities suggestive of ischemia (p = 0.03). Relative to those with PDs and inducible WMAs, myocardial oxygen demand remained different in these individuals with PDs without an inducible WMA after accounting for LV afterload and contractility (p = 0.02 and 0.03 respectively), but not after accounting for either LV stress related end diastolic volume index (LV preload) or resting concentricity (p = 0.31-0.71).

Conclusions

During dobutamine stress testing, elderly patients experience increased LV concentricity and declines in LV preload and myocardial oxygen demand, all of which are associated with an absence of inducible LV WMAs indicative of myocardial ischemia. These findings provide insight as to why dobutamine associated wall motion analyses exhibit reduced sensitivity for identifying inducible ischemia in elderly.

Trial registration

This study was registered with Clinicaltrials.gov ({"type":"clinical-trial","attrs":{"text":"NCT00542503","term_id":"NCT00542503"}}NCT00542503).     

Detection of left ventricular dysfunction by Doppler tissue imaging in patients with complete recovery of visual wall motion abnormalities 6 months after a first ST-elevation myocardial infarction

AIMS: The aim of this study was to assess left ventricular (LV) systolic and diastolic function, using Doppler tissue imaging (DTI), in patients with complete recovery of visual wall motion abnormalities six months after a first ST-elevation myocardial infarction (STEMI). METHODS: Out of 90 patients presenting with a STEMI, 68 patients without a history of heart disease were examined by echocardiography before discharge and after 6 months. The patients were compared to 41 age matched healthy subjects (HS). LV function was assessed by visual wall motion and mitral annular velocities using pulsed wave DTI. RESULTS: Sixty-eight patients had visual wall motion abnormalities at baseline. Of these, 19 patients showed complete recovery of wall motion at 6-months follow-up. Patients with complete recovery of wall motion abnormalities had significantly reduced peak systolic and peak early diastolic mitral annular velocities compared to HS at 6 months (8.3 cm s(-1) versus 9.9 cm s(-1), P<0.001 for systolic velocity and 9.3 cm s(-1) versus 13.1 cm s(-1), P<0.001 for diastolic velocity, respectively). CONCLUSION: In patients presenting with a first STEMI, mitral annular systolic and early diastolic velocities assessed by DTI at 6-months follow-up are significantly reduced compared to HS, despite normal standard echocardiographic parameters of LV function. This probably reflects a residual subendocardial damage not detected by conventional echocardiographic methods.     

Cine MR imaging after myocardial infarction – Assessment and follow-up of regional and global left ventricular function

Myocardial infarction often leads to regional wall motion defects and in case of large defects to remodeling of the left ventricle. With this study, changes in regional and global myocardial function of 12 patients 3 weeks after myocardial infarction and after revascularization therapy were determined using MRI. Cine MRI was performed at study entry at rest and during low-dose dobutamine stimulation. All patients were re-examined at rest 3 and 6 months after the revascularization, including analysis of wall thickening and of left ventricular end-diastolic volume index (LVEDVI), end-systolic volume index (LVESVI), ejection fraction (LVEF), and mass index. After revascularization, 6 patients with stress-induced improvement of regional wall thickening recovered, 4 patients without improvement did not, but 2 patients without stress-induced improvement of wall thickening also recovered. Concerning global cardiac function, patients with mainly improved regional wall motion also showed a lower LVESVI and a higher LVEF than patients without improvement of regional contractility 6 months after revascularization in comparison to study entry. In conclusion, improvement of global myocardial function after revascularization is higher in patients with improved contractility in the infarcted region. The extent of the response of regions with wall motion defects to dobutamine stress correlates with the actual improvement after revascularization, and, therefore, dobutamine stress MRI may be helpful in selecting patients that will have a higher benefit from a revascularization therapy.     

The role of short- and long-axis function in determining late diastolic left ventricular filling in patients with hypertension: Assessment by pulsed Doppler tissue imaging

Left ventricular (LV) wall motion velocity during atrial systole is mediated by both transmitral flow and LV myocardial compliance at end-diastole. LV wall distensibility along the long- and short-axis during atrial systole and late diastolic LV filling may vary according to the remodeling of LV morphology. We measured LV wall motion velocities along the long and short axes using pulsed Doppler tissue imaging in 127 patients with hypertension to evaluate the relationship between the hemodynamic changes and LV morphology and to determine the role of both long- and short-axis function in late diastolic LV filling. Participants were classified into 3 groups according to LV dimension and end-diastolic wall thickness determined by M-mode echocardiography: group A (n = 62) without LV dilation or hypertrophy, group B (n = 55) with LV hypertrophy, and group C (n = 10) with LV dilation and systolic dysfunction. The time constant of the LV pressure decay during isovolumic diastole and the LV end-diastolic pressure were longest and greatest, respectively, in group C, compared with groups B and A. There were no significant differences in active left atrial emptying volume during atrial contraction determined by computerized echocardiographic 3-dimensional reconstruction among patient and control groups. The peak atrial systolic motion velocity of the LV posterior wall along the long axis was significantly lower in groups B and C, particularly in the latter group, than in group A. The peak atrial systolic motion velocity of the LV posterior wall along the short axis was greatest in group B and was lowest in group C compared with the other groups, respectively. The peak atrial systolic motion velocity of the LV posterior wall was greater along the long axis than the short axis in group A, but was less than the short axis in group B. In conclusion, the long- and short-axis function of the LV wall during atrial systole varies in patients with hypertension according to the severity of hemodynamic and morphologic abnormalities. The degree of LV wall expansion along the short axis is an important factor resulting from the atrial kick, and a determinant of its effectiveness. (J Am Soc Echocardiogr 2002;15:1211-7.)     

应用速度向量成像技术研究正常左心室壁加速度

目的 尝试应用速度向量成像(velocity vector imaging,ⅤⅥ)技术研究正常左心室壁加速度特点.方法 50例健康志愿者,应用ⅤⅥ技术检测左室16个节段运动速度,应用研制的软件获得加速度一时间曲线.分析左室壁加速度分布特点.结果 同一室壁收缩早期正向峰值加速度(ACCs)和舒张早期负向峰值加速度(ACCd)表现为基底部＞中部＞心尖部(均P＜0.05),同一水平各室壁之间ACCs和ACCd差异均无统计学意义(均P＞0.05),同一节段ACCd显著大于ACCs(均P＜0.05).结论 VVI技术可研究室壁加速度特点,为进一步检测病变心肌加速度的变化提供正常依据.     

Myocardial viability independently influences left ventricular diastolic function in the early phase after acute myocardial infarction

BACKGROUND: After acute myocardial infarction, a broad range of left ventricular (LV) end-diastolic pressure (LVEDP) is expected because of chamber remodeling. However, intrinsic characteristics of the infarcted tissue (necrosis or viability) may also play a role. We aimed to evaluate whether myocardial viability (Mviab) has an influence on LVEDP. METHODS: One hundred twenty-three consecutive patients with acute myocardial infarction underwent low-dose dobutamine echocardiography (5-10 microg/kg/min) to assess Mviab. Mviab was quantitatively evaluated by the variation of Delta wall motion score index. Patients underwent left heart catheterization with recording of LVEDP and a complete echocardiographic examination with measurement of LV volumes, ejection fraction, and mass. RESULTS: The overall population (81% male; mean age 58 +/- 10 years) was divided into 2 groups according to the presence (group 1; 66 patients) or absence (group 2; 57 patients) of Mviab. LVEDP was higher in patients without Mviab (16 +/- 8 vs 20 +/- 7 mm Hg; P =.02). The multivariate analysis showed that Delta wall motion score index correlated with LVEDP (P =.01) independent of wall motion score index and LV end-systolic volume. CONCLUSIONS: After acute myocardial infarction, LVEDP shows wide variability and is independently associated with Mviab.     

Adverse effect of increased left ventricular wall thickness on five year outcomes of patients with negative dobutamine stress

Background

To determine if patients without dobutamine induced left ventricular wall motion abnormalities (WMA) but an increased LV end-diastolic wall thickness (EDWT) exhibit a favorable cardiac prognosis.

Results

Between 1999 and 2001, 175 patients underwent a dobutamine stress cardiovascular magnetic resonance (DCMR) procedure utilizing gradient-echo cines. Participants had a LV ejection fraction >55% without evidence of an inducible WMA during peak dobutamine/atropine stress. After an average of 5.5 years, all participants were contacted and medical records were reviewed to determine the post-DCMR occurrence of cardiac death, myocardial infarction (MI), and unstable angina (USA) or congestive heart failure (CHF) warranting hospitalization.In a multivariate analysis, that took into account Framingham and other risk factors associated with cardiac events, a cine gradient-echo derived LV EDWT ≥12 mm was associated independently with an increase in cardiac death and MI (HR 6.0, p = 0.0016), and the combined end point of MI, cardiac death, and USA or CHF warranting hospitalization (HR 3.0, p = 0.0005).

Conclusion

Similar to echocardiography, CMR measures of increased LV wall thickness should be considered a risk factor for cardiac events in individuals receiving negative reports of inducible ischemia after dobutamine stress. Additional prognostic studies of the importance of LV wall thickness and mass measured with steady-state free precession techniques are warranted.     

Aortic Doppler velocity measurement and cardiac function in the fetal lamb

Aortic haemodynamic parameters, and Doppler waveforms in particular, were investigated in acute experiments with fetal lambs. Cardiovascular changes were produced by central infusion of the drugs esmolol and dopamine. Pulsed Doppler waveforms were obtained from the descending thoracic aorta, simultaneous with recordings of pulsatile aortic volume flow rate, diameter and blood pressure. The relation between Doppler-derived velocities and the corresponding full vessel lumen velocities was shown to be fairly linear and consistent across different animals. The aortic volume flow per beat decreased with esmolol (p < 0.003, repeated measures ANOVA); the Doppler and vessel lumen mean velocities also decreased, whether measured only at peak systole or over the full cardiac cycle (at most p < 0.003). With dopamine the aortic flow per beat increased (p < 0.001), as did the Doppler and vessel lumen mean velocities (at most p < 0.02). An inverse relation between the aortic flow per beat and the peripheral resistance was observed. To identify inotropic changes in the presence of vascular effects, a theoretical model based on cardiac power output changes was implemented. The data were divided into three groups, according to whether the model did or did not identify a definite inotropic effect (positive or negative). The Doppler velocity changes for these three groups were different (p < 0.0001). The mean Doppler velocity increased by 7 cm s⁻¹ in the positive inotropic effect group, and decreased by 4 cm s⁻¹ in the negative group. The aortic flow parameters of the human fetus are very similar to those of the fetal lamb. Decreased aortic velocities have been reported in human fetal compromise, and the results of this study support the hypothesis that this can be evidence of impaired fetal cardiac function.     

定量组织速度成像和组织追踪对正常人左室壁运动的研究

目的应用定量组织多普勒速度成像(quantitative tissue velocity imaging,QTVI)和组织追踪法(tissue tracking,TT)分析正常人左室心肌长轴方向舒缩运动的特点,探讨QTVI和TT技术评价心肌运动的应用价值.方法获取标准心尖位左室长轴切面、两腔切面及四腔切面,分别应用QTVI和TT技术,对30例正常人左室各节段长轴方向舒缩运动的特点进行测定分析.结果正常人每个心动周期中,室壁运动速度曲线均包括收缩波(S)、快速充盈波(E)和左房收缩充盈波(A)三个主要运动波,以及等容舒张波(IR)和等容收缩波(IC).正常人心肌不同节段收缩期和舒张期运动速度呈一梯度.同一室壁从心底向心尖部,运动速度和位移逐渐降低.同一水平不同节段心肌运动速度和位移也有差别.结论正常人室壁运动存在特有的不均一性,QTVI和TT对评价局部心肌运动具有很好的应用价值,进而为诊断冠心病开辟一种新途径.     

Effect of aging on diastolic left ventricular myocardial velocities measured by pulsed tissue Doppler imaging in healthy subjects.

We evaluated the effect of aging on diastolic left ventricular (LV) wall motion velocity in 80 healthy persons with the use of pulsed tissue Doppler imaging. The wall motion velocity patterns were recorded at the middle regions of the LV posterior wall and ventricular septum in the parasternal (along the short axis) and apical (along the long axis) LV long-axis views. In the posterior wall, the peak early diastolic wall motion velocities (Ews) along both axes correlated inversely with age (long axis: r = -0.61, P <. 0001; short axis: r = -0.55, P <.0001), and the peak atrial systolic wall motion velocities(Aws) along both axes correlated directly with age (long axis: r = 0.59, P <.0001; short axis: r = 0.65, P <.0001). In the ventricular septum, the Ew along the long axis correlated inversely with age (r = -0.51, P <.0001), and the Aws along both axes correlated directly with age (long axis: r = 0.57, P <.0001; short axis: r = 0.53, P <.0001). The Ews along both axes at the posterior wall correlated directly with the peak early diastolic transmitral flow velocity. The Aws along both axes at the ventricular septum and posterior wall correlated directly with the peak atrial systolic transmitral flow velocity. The times from the second heart sound to the peak of the early diastolic waves of the ventricular septum and posterior wall along both axes significantly increased with age. The times from the aortic component of the second heart sound to the peak of the early diastolic motion velocities along both axes were significantly longer at the ventricular septum than at the posterior wall. Pulsed tissue Doppler imaging may be useful for evaluating the effect of aging on diastolic LV function in healthy persons.     

定量组织速度成像技术评价急性心肌梗死后左室重构的左室功能

目的应用定量组织速度成像技术对心肌梗死后左室重构的左心功能进行评价,以探讨其应用价值.方法用定量组织速度成像技术测定22例健康者及临床确诊的29例心肌梗死后左室重构的冠心病患者的左室壁各节段的收缩期峰值速度(VS),舒张早期速度(VE),舒张晚期速度(VA)和VE/VA比值.测定二尖瓣口血流频谱的快速充盈速度(E),左房收缩充盈速度(A)和E/A值.容积法测左室射血分数,左室舒张末期容积指数(LVEDVI),左室收缩末期容积指数(LVESVI)及球形指数,并与正常组比较.结果心脏左室长轴方向上心梗组前壁,侧壁,下壁各节段,后间隔心尖段Vs明显下降(P＜0.01),后间隔基底段和中间段Vs无明显差异(P＞0.05);心梗组几乎各节段VE、VA、VE/VA与正常组相比有显著差异(P＜0.05).各节段平均VS与左室射血分数,球形指数等呈线性相关(r值分别为0.79,0.68,P＜0.01),舒张期功能参数平均VE/VA与二尖瓣E/A比值之间存在高度相关性(r=0.62,P＜0.01).心梗组LVEDVI和LVESVI明显增大(P＜0.01).结论定量组织速度成像可客观定位定量的反映心肌梗死局部心肌组织的收缩及舒张功能,又能体现心肌梗死后左室重构的整体功能,为心肌梗死后左室重构的心功能的评价提供了客观依据.     

定量组织多普勒速度图评价不同孕周正常胎儿心脏室壁运动

目的探讨超声定量组织多普勒速度成像技术(QTVI)评价正常胎儿心室壁运动的临床价值。方法运用彩色组织多普勒速度成像图对100例孕18~40周正常胎儿心脏进行检测,在心尖四腔图切面,对左右心室壁及室间隔的9个观察点的速度曲线进行分析,测量收缩期运动速度Vs,舒张早期运动速度Ve,舒张晚期运动速度Va,并进行分析和统计学处理。结果正常胎儿心室壁运动速度的变化趋势为基底部>中部>心尖部,左心室、间隔收缩期运动速度相近,右心室收缩期运动速度略高于左心室及间隔,在舒张晚期间隔与左心室的速度相近,但低于右心室。室壁运动速度随孕周增加亦增加。结论组织多普勒速度成像技术用于评价胎儿室壁运动是可行的,它安全、准确、可靠。     

Quantitative Doppler tissue imaging as a correlate of left ventricular contractility

Doppler tissue imaging is a new noninvasive imaging modality that allows quantitation of the low intensity, high amplitude Doppler shifts in the range of myocardial tissue motion. This study was performed to test the hypothesis that Doppler tissue imaging may provide unique information reflecting left ventricular systolic function, and to test the relationship between myocardial tissue velocity and noninvasive measures of ventricular contractility. Nine patients with mild or moderate mitral insufficiency and no regional wall motion abnormality were studied during dobutamine stress echocardiography. Left ventricular ejection fraction and peak systolic velocity of the sub- endocardial left ventricular posterior wall were quantified at baseline and at peak stress and compared with estimated peak dP/dt. During dobutamine infusion, ejection fraction increased from 41.7±22.2 (range 14 to 70) % to 56.6±27.9 (range 17 to 84) % (p=0.001), peak systolic velocity increased from 22.7±4.2 (range 18 to 28) mm/sec to 35.3±10.1 (range 20 to 47) mm/sec (p=0.004), and dP/dt increased from 1050±322 (range 613 to 1574) mm Hg/sec to 1766±768 (range 936 to 3000) mm Hg/sec (p=0.01). Although there were good correlations between left ventricular dP/dt and both ejection fraction (R=0.75) and peak systolic velocity (R=0.81), the correlation between change in dP/dt and change in myocardial velocity (R=0.75) was better than that between change in dP/dt and change in ejection fraction (R=0.36). These data support the hypothesis that myocardial velocity determined with Doppler tissue imaging reflects myocardial contractility, and that catecholamine- induced alteration in contractility is better reflected by changes in myocardial velocity than by changes in ejection fraction.     

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。     

Influence of aging on systolic left ventricular wall motion velocities along the long and short axes in clinically normal patients determined by pulsed tissue doppler imaging.

Our objective was to evaluate the influence of aging on left ventricular (LV) regional systolic function along the long and short axes in clinically normal patients. We recorded LV wall motion velocity patterns at the mid-wall portion of the middle of the LV posterior wall in the parasternal long-axis view (short-axis direction) and at the endocardial portion of the middle of the LV posterior wall in the apical long-axis view (long-axis direction) with pulsed tissue Doppler imaging in 80 normal patients (age range 15 to 78 years). In all patients the LV pressure curve and its first derivative (dP/dt) were recorded. The systolic wave of the LV posterior wall motion velocity pattern exhibited 2 peaks, the first (Sw(1)) and second (Sw(2)) systolic waves. No significant changes were seen with aging in the percent LV fractional shortening determined by M-mode echocardiography, LV ejection fraction determined by left ventriculography, the peak Sw(1) and Sw(2) along the short axis, the peak Sw(2) along the long axis, and the peak dP/dt. The peak Sw(1) along the long axis correlated inversely with age (P <.0001) but did not correlate significantly with the peak dP/dt. These results suggest that shortening of the longitudinal fibers in early systole is impaired with increased age in healthy individuals. This impairment results in insufficient spherical change in the LV cavity, although global LV pump function and myocardial contractility are maintained.