Assessment of left ventricular systolic and diastolic function by Doppler tissue imaging in patients with preinfarction angina.

BACKGROUND: The aim of this study was assessment of left ventricular (LV) systolic and diastolic function by pulsed wave Doppler tissue imaging (DTI) in patients with or without preinfarction angina in acute myocardial infarction. METHODS: We prospectively evaluated 31 consecutive patients (4 women, 27 men; age 58 +/- 10 years) with a first acute myocardial infarction. LV systolic and diastolic function was assessed by classic methods and DTI on the third day during acute myocardial infarction. Patients were divided into 2 groups according to the presence (group 1; n = 10) or absence (group 2; n = 21) of preinfarction angina. Mitral inflow velocities and early diastolic mitral annular velocity (Em), late diastolic mitral annular velocity (Am), peak systolic mitral annular velocity, Em/Am, the ratio of early diastolic mitral inflow velocity (E) to Em, and myocardial performance index were calculated by DTI. RESULTS: Group 1 had significantly higher Em and Em/Am than group 2 (11.3 +/- 3.34 cm/s vs 7.4 +/- 2.07 cm/s, P <.0001; 1.01 +/- 0.38 cm/s vs 0.6 +/- 0.2 cm/s, P =.001, respectively). The E/Em ratio and myocardial performance index were significantly lower in group 1 than in group 2 (5.1 +/- 2.92 vs 8.10 +/- 3.15, P=.018; 0.49 +/- 0.15 vs 0.65 +/- 0.24, P =.042, respectively). Wall-motion score index was lower in those with preinfarction angina than in those without (1.6 +/- 0.36 vs 1.9 +/- 0.39; P =.04, respectively). Peak systolic mitral annular velocity and Am were not statistically different between groups (9.4 +/- 1.84 vs 8.3 +/- 2.03, P =.172; 11.7 +/- 3.07 vs 12.1 +/- 3.34, P =.72, respectively). There were no significant differences between the 2 groups regarding transmitral E velocity, atrial contraction mitral inflow velocity (A), E/A ratio, isovolumetric relaxation time, and deceleration time of the mitral E wave (P =.91, P =.08, P =.58, P =.81, and P =.71, respectively). CONCLUSION: LV diastolic function was better in patients with preinfarction angina than in patients without. This condition could not be detected by conventional mitral inflow Doppler velocities, but could be detected by DTI. This preliminary evidence shows that DTI is better than conventional mitral Doppler indices in the assessment of a favorable LV diastolic function in patients with preinfarction angina.     

定量组织速度成像与二维应变成像评价冠心病左心室局部收缩功能

目的 应用定量组织速度成像(QTVI)及二维应变(2DS)检测冠心病患者心肌运动速度和应变率(SR)的变化,探讨其评价冠心病患者心肌局部收缩功能的价值.方法 对心绞痛组20例,心肌梗死组25例,正常对照组30名,应用QTVI及2DS分别获得左心室乳头肌水平短轴切面的动态图像,通过测量前壁和下壁心内膜下心肌收缩期运动速度(Vendo)和心外膜下心肌收缩期运动速度(Vepi),计算相应心肌的应变率(TVI-SR),并用2DS测量局部心肌的应变率(2DS-SR).结果 三组左心室下壁的运动幅度、室壁增厚率、速度和SR差异均无统计学意义.与正常对照组比较,心绞痛组和心肌梗死组前壁的Vendo、TVI-SR、2DS-SR明显下降;与心绞痛组比较,心肌梗死组前壁上述指标也均明显下降,且较室壁运动幅度和室壁增厚率下降明显.结论 QTVI和2DS可以敏感地评价心肌缺血时心脏局部收缩功能.     

Can changes in systolic longitudinal deformation quantify regional myocardial function after an acute infarction? An ultrasonic strain rate and strain study.

OBJECTIVES: The aim of this study was to evaluate the additional value of ultrasonic strain rate and strain to myocardial velocity in the identification and quantification of regional asynergy after an acute myocardial infarction (MI). METHODS: Forty patients (59 +/- 13 years) were investigated 3 +/- 2 days after a first infarction and compared with 14 age-matched controls with normally contracting segments (group A, n = 146). Longitudinal myocardial velocities, strain rate (SR) and strain (epsilon) were postprocessed from basal, mid, and apical segments interrogated using apical views. In a subset of patients with coronary angiograms (n = 24), myocardial segments were divided into 3 groups: normally contracting segments supplied by a normal coronary artery (group B1), normally contracting segments supplied by a diseased coronary artery (group B2), and segments with abnormal motion (group B3). Velocities were decreased in patients with myocardial infarction (MI) (P <.05 vs controls) but failed to accurately differentiate normally from abnormally contracting segments. At the opposite end, systolic SR and epsilon decreased significantly with segmental asynergy severity and could identify infarct-involved segments (group B3) with a sensitivity/specificity of 85% (systolic SR and epsilon cutoff values of -0.8 s(-1) and -13%, respectively). CONCLUSION: Strain rate and strain can better assess segmental dysfunction severity than myocardial velocities alone after an acute MI.     

Subendocardial motion in hypertrophic cardiomyopathy: assessment from long- and short-axis views by pulsed tissue Doppler imaging.

BACKGROUND: Tissue Doppler imaging (TDI) is a recently developed technique that allows the instantaneous measurement of intrinsic regional myocardial motion velocity. Pulsed TDI is capable of separately assessing left ventricular (LV) regional motion velocity caused by circumferential and longitudinal fiber contraction. This particular feature of function is still controversial in patients with hypertrophic cardiomyopathy (HC). METHODS: To better characterize intrinsic circumferential and longitudinal LV systolic myocardial function in HC, we used pulsed TDI to measure short- and long-axis LV motion velocities, respectively. The subendocardial motion velocity patterns at the middle of the LV posterior wall (PW) and ventricular septum (IVS) in LV parasternal and apical long-axis views were recorded by pulsed TDI in 19 patients with nonobstructive HC and in 21 normal controls (NC). RESULTS: Peak short- and long-axis systolic subendocardial velocities in both the LV PW and IVS were significantly smaller in the HC group than in the NC group, and the time to peak velocity was significantly delayed. Furthermore, peak PW systolic velocity was significantly greater along the long axis than along the short axis in the NC group (8.8 +/- 1.5 cm/s vs 8.2 +/- 1.4 cm/s, P <.05), whereas the opposite was observed in the HC group (6.1 +/- 1.2 cm/s vs 7.5 +/- 1.0 cm/s, P <.0001). No significant differences were found in either group between the long- and short-axis IVS velocities (HC: 5.9 +/- 1.4 cm/s vs 5.5 +/- 1.3 cm/s; NC: 7.8 +/- 1.3 cm/s vs 7.9 +/- 1.6 cm/s). CONCLUSIONS: By using the capability of pulsed TDI for the evaluation of intrinsic myocardial velocity instantaneously in a specific region and direction, we found impairment of LV myocardial systolic function in patients with HC not only in the hypertrophied IVS but also in the nonhypertrophied LV PW. We also found a greater decrease in LV PW velocities along the long axis than the short axis, suggesting greater impairment of long-axis contraction in patients with HC. Because our HC patients did not appear to have excessive intracavitary pressure, these results suggest that the relatively normal-appearing PW is directly affected by the HC pathologic process.     

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.     

Tissue cardiovascular magnetic resonance demonstrates regional diastolic dysfunction in remote tissue early after inferior myocardial infarction.

PURPOSE: To investigate regional diastolic and systolic function using tissue cardiovascular magnetic resonance (CMR), early after transmural myocardial infarction of the inferior wall due to single proximal right coronary artery disease. MATERIALS AND METHODS: Velocity encoded CMR was used to measure early diastolic transmitral flow velocity (E), and regional, longitudinal, myocardial systolic (Sa) and early diastolic (Ea) velocities (tissue CMR) in 15 patients with a recent transmural inferior myocardial infarction and in 15 age and LV-mass index matched control subjects. An unpaired two-tailed t test was used to assess significance of continuous variables. RESULTS: Global systolic (ejection fraction 46 +/- 7% versus 57 +/- 4%, p = 0.000052) and global diastolic LV function (average Ea of infarcted or inferior, remote or anterior, adjacent or septal and lateral myocardium 6.8 +/- 1.7 cm/s versus 10.4 +/- 1.5 cm/s, p = 0.0000012) were impaired in patients as compared to controls. Regional systolic and diastolic LV velocities were impaired in infarcted and adjacent tissue in patients. However, in remote or anterior tissue, systolic velocities were preserved (Sa 6.6 +/- 2.0 cm/s versus 6.8 +/- 1.4 cm/s, p = 0.70), but diastolic velocities were impaired in patients as compared to controls (Ea 7.2 +/- 2.3 cm/s versus 10.2 +/- 2.5 cm/s, p = 0.0026). CONCLUSIONS: Regional diastolic velocities early after inferior myocardial infarction are impaired in the infarcted, adjacent and remote tissue, but regional systolic velocities are preserved in remote tissue.     

Association of severe coronary stenosis with subclinical left ventricular dysfunction in the absence of infarction.

BACKGROUND: Regional left ventricular (LV) dysfunction may occur in patients with coronary artery disease (CAD) in the absence of infarction, but the causes of this phenomenon are unclear. We sought to identify whether changes in regional LV function were related to stenosis severity, using sensitive new ultrasound markers of function. METHODS: We studied 67 individuals with no history of infarction and with normal LV systolic function: 49 patients with CAD and 18 control subjects without CAD. All patients underwent color Doppler tissue imaging, integrated backscatter (IB), anatomic M-mode echocardiography, and strain rate imaging to detect changes in structure and function. Peak early and late diastolic myocardial velocity, cyclic variation of IB, wall thickness, and percent wall thickening were measured in each basal and mid segment. Strain rate and peak systolic strain were calculated in each wall. CAD was defined as >or=50% diameter stenosis. Normokinetic segments (n = 354) subtended by CAD were divided according to stenosis severity into 3 groups: group 1 (subtended by 50%-69% stenosis); group 2 (subtended by 70%-98% stenosis); and group 3 (subtended by >or=99% stenosis). Each parameter in each group was compared with that in 216 segments from control subjects. RESULTS: Segments subtended by significant CAD showed lower peak early and late diastolic myocardial velocity compared with control segments. Group 3 showed significantly lower myocardial velocities than group 2 for both peak early (4.8 +/- 1.8 vs 6.0 +/- 2.0 cm/s, P <.05) and late (4.5 +/- 2.1 vs 5.6 +/- 2.1 cm/s, P <.05) diastolic myocardial velocity. Group 3 also showed a significantly lower cyclic variation IB than did control segments (6.7 +/- 2.3 vs 7.9 +/- 2.6 dB, P <.05), but there was no difference in calibrated IB, wall thickness, strain parameters, or percent wall thickening. These differences were not attributable to the distribution of segments for patients with severe CAD, nor were they explained on the basis of collaterals. CONCLUSION: Although the absolute values show overlap between groups, the results of this study indicate that subtle changes of regional LV function may occur in the absence of infarction, in association with severe coronary stenoses.     

Diagnosis of viable myocardium using velocity data of Doppler myocardial imaging: comparison with positron emission tomography.

To test whether velocity data of Doppler myocardial imaging (DMI) at rest is useful for diagnosis of myocardial viability, 25 consecutive patients (age 64 +/- 10 years) with regional wall-motion abnormalities at the left anterior descending coronary artery territory and left ventricular dysfunction (ejection fraction: 31 +/- 7%) underwent both DMI at rest and positron emission tomography. The peak systolic velocity (Vpeak) and postsystolic thickening (PST) velocity were measured in myocardial segments of left anterior descending coronary artery territory from apical views. A total of 71 segments were classified by positron emission tomography as normal or viable in 38 (group A) and nonviable in 33 (group B). Although Vpeak did not show any difference between groups (1.81 +/- 1.77 vs 1.29 +/- 0.94 cm/s, P =.107), PST velocity was significantly higher in group A (2.48 +/- 1.68 vs 0.89 +/- 0.72 cm/s, P <.001). The sensitivity and specificity of PST velocity > 2.0 cm/s for diagnosis of viability were 61% (23/38) and 97% (32/33), respectively. In segments with PST velocity was < or =2.0 cm/s, Vpeak > 1.8 cm/s could discriminate group A from B with a sensitivity of 67% (10/15) and a specificity of 91% (29/32). The algorithm using both PST velocity and Vpeak of DMI showed sensitivity and specificity of 87% and 88%, respectively, for diagnosis of myocardial viability. Velocity data of DMI at rest provides robust information regarding viability in selected patients, and an advantage of this technique is that no stress testing is needed.     

二维斑点追踪成像对冠心病左室心肌局部收缩功能异常的研究

目的 运用二维斑点追踪成像（STI）测量正常人及心绞痛、心肌梗死患者左心室各节段的二维应变值,探讨二维斑点追踪技术对节段性心肌缺血的临床价值.方法 心绞痛患者73例,心肌梗死患者67例,健康对照组50例,分别采集其左心室长轴和短轴方向的二维动态图像,测量心肌收缩期峰值的纵向应变、径向应变和圆周应变.结果 对照组应变曲线排列规律,纵向应变由基底部到心尖部递增;同一水平室间隔周向应变较高;径向应变在同一水平不同节段分布较一致.心绞痛组、心肌梗死组缺血室壁节段纵向应变、径向应变和圆周应变减低,应变曲线紊乱;心绞痛组纵向应变、径向应变较对照组减低（P〈0.05）,心肌梗死组纵向应变、径向应变和圆周应变较对照组和心绞痛组均减低（P〈0.05）.结论 STI能够准确测量左室心肌节段的二维应变值,定量评价心肌缺血程度,纵向应变和径向应变是冠心病早期心肌缺血的敏感指标.     

Decreased left ventricular longitudinal contraction in normotensive and normoalbuminuric patients with Type II diabetes mellitus: a Doppler tissue tracking and strain rate echocardiography study

Type II diabetes mellitus is associated with congestive heart failure with preserved ejection fraction. This group of patients has been assumed to have isolated diastolic dysfunction; however, the longitudinal systolic contraction of the left ventricle has not been studied previously. The objective of the present study was to investigate the longitudinal contraction of the left ventricle in normotensive Type II diabetes mellitus patients with normal ejection fraction. We examined 32 normotensive patients with Type II diabetes mellitus with ejection fraction >0.55 and fractional shortening >0.25. Exclusion criteria were angina pectoris, cardiac valve disease, albuminuria, retinopathy or neuropathy. Normal subjects (n =32) served as controls. A 16 segment model of motion amplitude assessed left ventricular longitudinal contraction and the average of the segments was calculated as the tissue tracking score index. Peak systolic velocity and strain rate was also obtained in each segment. Patients with Type II diabetes mellitus had a significantly lower tissue tracking score index compared with normal subjects (5.8+/-1.6 mm compared with 7.7+/-1.1 mm; P <0.001). Mean peak systolic velocity was also significantly lower (4.3+/-1.5 cm/s compared with 5.4+/-1.0 cm/s; P <0.001), as well as peak systolic strain rate (-1.2+/-0.3 s(-1) compared with -1.6+/-0.4 s(-1); P <0.001). Patients with Type II diabetes mellitus and preserved diastolic function had a significantly lower tissue tracking score index compared with normal subjects (6.6+/-1.5 mm; P <0.001), but patients with diastolic dysfunction had an even more profound decrease in tissue tracking score index compared with patients without diastolic dysfunction (4.9+/-0.9 mm; P <0.01). In conclusion, the longitudinal systolic contraction was significantly decreased in normotensive patients with Type II diabetes mellitus with normal ejection fraction, which was most profound in patients with concomitant diastolic dysfunction.     

Recovery of stunned myocardium in acute myocardial infarction quantified by strain rate imaging: a clinical study.

BACKGROUND: Strain rate (SR) imaging (SRI) is a tissue Doppler-based method of regional myocardial deformation imaging. The aim of this study was to see whether SRI could quantify changes in myocardial mechanical function after an acute myocardial infarction, and to follow the time course of these changes. METHODS: In all, 26 consecutive patients with first-time acute myocardial infarctions were examined on days 1, 7, and 90. Segments were analyzed with SRI and wall-motion score. RESULTS: Peak systolic SR in infarcted segments increased significantly in magnitude from day 1 to 7 (-0.45 to -0.68 s -1 , P < .001), but not after day 7. The deformation rate in border zone segments also increased significantly from day 1 to 7 (-0.8 to -0.95 s -1 , P < .05), with no further significant changes at 3 months. In normal segments, peak systolic SR decreased in magnitude during the first week. Systolic strain showed similar results as peak systolic SR. CONCLUSION: SRI can demonstrate small changes in deformation rate from midinfarct through the infarct and border zone to normal myocardium. It can also show changes over time, probably as a result of recovery of stunned myocardium.     

Analysis of athletes’ heart by tissue Doppler and strain/strain rate imaging

After regular and prolonged training, some physical and structural changes occur in the heart. Strain (S) imaging and Strain Rate (SR) imaging are new and effective techniques derived from tissue Doppler imaging (TDI) which examine systolic and diastolic functions. The aim of the present study was to evaluate left ventricular TDI and S/SR imaging properties in athletes and sedentary controls. The study population consisted of 26 highly trained athletes (group I) and age, sex and body mass index (BMI) adjusted 23 control subjects (group II) who had no pathological conditions. Using standard transthoracic and Doppler echocardiographical measurements and reconstructed spectral pulsed wave tissue Doppler velocities, the S/SR imaging of six different myocardial regions were evaluated. There was a significant increase in left ventricular systolic (LVSD) and diastolic (LVDD) diameter, inter-ventricular septum (IVS), left ventricular mass (LVm), left atrial diameter (LA), and transmitral Doppler peak E velocity (flow velocity in early diastole) between group I and group II in the case of echocardiographic findings. In athletes, TDI analysis showed a significantly increased mitral annulus lateral TDI peak early diastolic (E) velocity (18.8 ± 4.1 cm/s vs. 15 ± 3.5 cm/s, P < 0.01), septal TDI peak E velocity (15.8 ± 2.8 cm/s vs. 12.8 ± 2.4 P < 0.001). There were no significant differences in myocardial velocity imaging parameters between group I and group II. Peak systolic strain/strain rates of septal and lateral walls in group I were significantly higher than group II. This study demonstrates that left ventricular S/SR imaging was higher in athletes than in healthy subjects. In addition to traditional echocardiographic parameters, SI/SRI could be utilised as a useful echocardiographic method for cardiac functions of athletes.     

Strain rate imaging for the assessment of preload-dependent changes in regional left ventricular diastolic longitudinal function.

BACKGROUND: Strain rate imaging is a new and intriguing way of displaying myocardial deformation properties by means of echocardiography. With high frame rate strain rate imaging we observed a spatial inhomogeneity in diastolic longitudinal strain rates in healthy persons. A base-to-apex time delay in diastolic lengthening could be seen both in early diastole and at atrial contraction. METHODS AND RESULTS: We investigated this consistent finding and its dependence on loading conditions in 20 healthy volunteers. Propagation velocities of lengthening of 91 +/- 31 cm/s (E-wave) and 203 +/- 11 cm/s (A-wave) at rest (equal to time delays of 104 +/- 29 ms and 56 +/- 24 ms, respectively) increased significantly to 101 +/- 27 cm/s (E) and 283 +/- 17 cm/s (A) with lifting the volunteers' legs. Applying nitroglycerin sublingually and sitting upright significantly decreased propagation velocities (E-wave 76 +/- 20 cm/s, A-wave 172 +/- 93 cm/s and E-wave 66 +/- 17 cm/s, A-wave 150 +/- 64 cm/s, respectively). Free lateral walls showed a lower propagation velocity than septal walls. CONCLUSION: We conclude that the propagation velocities of left ventricular lengthening waves are dependent on preload changes and increase with increasing preload.     

Quantitative regional analysis of left atrial function by Doppler tissue imaging-derived parameters discriminates patients with posterior and anterior myocardial infarction.

BACKGROUND: Doppler tissue imaging can now be used for the assessment of left atrial (LA) function. LA function was evaluated by this technique in a group of patients hospitalized for acute myocardial infarction and in a control population. METHODS: Patients were all prospectively imaged with a scanner. To study the LA, a region of interest was located in the proximal part of the lateral and septal LA walls. Doppler tissue imaging, tissue tracking, strain, and delays were recorded. RESULTS: In all, 12 patients with posterior (age 54 +/- 9 years) and 13 with anterior (age 64 +/- 16 years) acute myocardial infarction, along with 16 control patients (age 54 +/- 9 years), were analyzed. Early diastolic septal velocity was found to be the best parameter for discriminating among the 3 groups. Peak strain was also relevant and did not correlate with left ventricular function. CONCLUSIONS: LA is accessible to Doppler tissue imaging analysis. Strain can quantify LA function relatively independently of left ventricular function, and may provide new insights on LA function.     

组织多普勒成像评价择期冠状动脉介入治疗对急性心肌梗死患者左心室功能和同步性的影响

目的 应用组织多普勒成像（TDI）评价择期冠状动脉介入治疗（PCI）对急性ST段抬高型心肌梗死（ASTEMI）患者左心室收缩、舒张功能及同步性的短期影响.方法 收集因首次ASTEMI住院并接受择期PCI治疗的患者51例.根据冠状动脉造影及室壁运动状态将心肌分为梗死组（MI组,n=89）、缺血组（ISCHE组,n=93）及对照组（Con组,n=117）.于术前3d内及术后1个月行常规超声和TDI检查.测得左心室整体收缩及舒张功能指标、左心室局部心肌功能指标及收缩同步性指标进行比较.结果 术后1个月,左心室舒张末内径（LVEDD）、收缩末内径（LVESD）及收缩末容积（LVESV）缩小[（56.00±2.95）mm vs.（54.42±3.50）mm;（33.83±4.24）mm vs.（31.42±3.82）mm;（45.58±9.40）ml vs.（43.25±9.64）ml;P＜0.05];射血分数（LVEF）增加[（56.42 ±5.93）％ vs..（58.92±5.32）％,P＜0.01];二尖瓣环收缩期峰速度（S＇a）增加[（8.60±2.25） cm/s vs.（11.86±2.66） cm/s,P＜0.05];二尖瓣舒张早期血流速度/二尖瓣环舒张期峰速度（E/Ea）减小（6.91±1.06 vs.5.52±1.18,P＜0.01）;左心室12节段收缩期纵向速度达峰时间标准差T-SD有减小趋势,但未见统计学差异[（42.37±20.41） ms vs.（37.60±17.07） ms,P＞0.05].ISCHE组心肌应变（S）增加[（12.73±4.96）％ vs.（15.02±4.70）％,P＜0.05],但MI组无变化[（11.33±4.99）％ vs.（12.56±5.10）％,P＞0.05].结论 择期PCI可短期内改善ASTEMI患者左心室整体收缩、舒张功能和缺血心肌的功能.组织应变成像（SI）可敏感、准确地评价左心室整体及局部心肌功能.     

Cardiac rehabilitation after coronary artery bypass grafting: effects on exercise performance and risk factors

After coronary artery bypass grafting (CABG), 49 nonselected patients followed a cardiac rehabilitation program that included medical follow-up and physical training, both in outpatient groups and on an individual basis at home. The effect of the program on exercise test variables, coronary risk factors, and medication one year after surgery was compared to a nonexercised control group (n = 98). The study group showed less increase in the rate-pressure product, indicating a favorable effect on myocardial oxygen consumption (0.7 +/- 5.4 vs 2.8 +/- 5.6, p less than .05); a lower frequency of angina at exercise testing (6% vs 18%, p less than .01); a reduction in resting systolic and diastolic blood pressure (9/4mmHg, p less than .01); fewer smokers (6% vs 17%, p less than .05); and fewer patients taking long-acting nitrates (0% vs 10.2%, p less than .05). It is suggested, therefore, that an organized cardiac rehabilitation program may be advantageous after CABG.     

Reducing the cyclic variations of ultrasonic integrated backscatters and myocardial electrical synchronism by reversibly blocking intercellular communications with heptanol

The purpose of this study is to provide direct evidence for the role of intercellular communications in electrical synchronization and mechanical function of myocardium. We used heptanol, a reversible inhibitor of gap junctions, at low (0.16 mM) and high (0.5 mM) concentration as perfusate for 18 Langendorff-perfused rabbit hearts to study its effects on myocardial electrical and mechanical functions. Optical mapping was performed to measure conduction velocity (CV) and action potential duration (APD). Ultrasonic integrated backscatter and Doppler tissue imaging (DTI) were used to evaluate the intrinsic and global myocardial contractile performance. The CV decreased during low-dose heptanol infusion and became much slower at high dose (high dose vs. baseline, 50.8 +/- 10.2 cm/s vs. 69.3 +/- 8.8 cm/s, p < 0.001). After washout of heptanol, CV completely recovered. The alterations of APD by heptanol infusion were similar to CV. The APD dispersion, standard deviation of APD(80), was increased after heptanol infusion (low dose vs. baseline, 5.9 +/- 1.1 ms vs. 4.3 +/- 1.1 ms, p = 0.004; high dose, 6.0 +/- 1.3 ms, vs. baseline, p = 0.035). However, washout did not restore the APD dispersion which became even larger after washout (13.6 +/- 1.9 ms vs. high dose and baseline, both p < 0.001). Regarding contractile function, heptanol treatment resulted in a progressive decrease of cardiac cycle-dependent variations of integrated backscatter (CVIBS; low dose vs. baseline, 6.1 +/- 1.7 dB vs. 7.2 +/- 1.8 dB, p = 0.007; high dose 1.7 +/- 0.3 dB vs. baseline, p < 0.001) and peak systolic strain rate (low dose vs. baseline, -1.5 +/- 0.6 1/s vs. -1.9 +/- 0.6 1/s, p = 0.014; high dose -0.4 +/- 0.2 1/s; vs. baseline, p < 0.001). That both CVIBS and strain rate incompletely recovered after heptanol washout may be attributed to the increased APD dispersion. In conclusion, uncoupling of gap junctions resulted in slowing CV, increased repolarization heterogeneity, reduced CVIBS and impaired myocardial contractility. There was a reversible dose-response relationship between the myocardial electromechanical functions and gap junction coupling.     

干预急性冠脉综合征患者肺炎衣原体感染对其预后的影响

目的探讨阿奇霉素对急性冠脉综合征(ACS)患者肺炎衣原体(chlamydia pneumonia,Cpn)感染、再发冠心病事件及血炎症介质的影响。方法伴Cpn感染的51例不稳定型心绞痛、107例急性心肌梗死患者随机分为对照组(80例)和治疗组(78例),治疗组口服阿奇霉素500mg/d,共3d,而后每周日口服500mg,共4周。结果随访12个月,冠心病事件在治疗组的发生率为14.10%,对照组为30.00%,治疗组相对危险降低53.00%(P=0.0179),其中非致死性急性心肌梗死治疗组为6.75%,对照组为15.85%,治疗组相对危险降低61.37%(P=0.0341);其他事件的发生率治疗组为14.10%,对照组为38.75%,治疗组相对危险降低63.61%(P=0.0050),其中治疗组因心绞痛入院者为7.69%,对照组为20.00%,治疗组相对危险降低61.55%(P=0.0256),PCI/CABG在治疗组为3.85%,对照组为13.75%,治疗组相对危险降低72.00%(P=0.0297)。治疗组血炎症介质水平在治疗后与治疗前及对照组相同时间点比较显著降低(P<0.05或P<0.01)。结论阿奇霉素治疗可降低非致死性急性心肌梗死的发生率、因心绞痛入院率,减少对PCI/CABG的需求,并能降低血炎症介质水平,表明抗感染治疗在冠心病二级预防中起到有益的作用。     

应变率成像及实时三维超声心动图定量评价早期2型糖尿病兔左室心肌运动及功能

目的探讨超声应变率成像（SRI）及实时三维超声心动图（RT3DE）评价早期2型糖尿病兔左室心肌运动及功能的价值。方法通过静脉注射致病剂量链脲左菌素（STZ），诱发兔高血糖，制备2型糖尿病兔模型；应用SRI技术，分别观测正常兔（NC组，8只）、糖尿病兔（DM组，13只）左室心肌不同节段的收缩期平均峰值速度（PSV）、平均峰值应变率（PSSR）和平均峰值应变（PSS）、舒张早期峰值应变率（SRe）；应用RT3DE检测左心射血分数（EF）。应用脉冲多普勒测量二尖瓣血流速度（Ea、Aa）并计算Ea／Aa值。结果DM组各节段收缩期V、SR、S、SRe与NC组相应节段相比明显减低（P〈0．05）；同时，DM组左心收缩、舒张功能较NC组减低（P〈0．05）；DM组SRe值与Ea／Aa值之间密切相关（r=0．93，P〈0．01）。结论2型糖尿病兔早期即出现心肌运动及功能异常；应变率及实时三维成像能直观、无创地定量评价兔局部心肌功能及整体心功能。