急性心肌梗死超急性期的超声诊断

目的 研究急性心肌梗死(AMI)超急性期时的心肌组织超声背向散射积分(IBS)的变化及对临床诊断AMI超急性期的价值.方法 将72例AMI患者分成2组:超急性期组(梗死时间在2 h以内)30例,急性期组42例(梗死时间>2 h,有典型的心电图改变);另取正常对照组30例.用HP-5500型超声诊断仪,分别测量心肌梗死区域和非梗死区域心肌组织的心动周期时间平均背向散射积分(IBS),并将其与心包IBS的比值作为心肌IBS的校正值(IB%),舒张末期与收缩末期的IBS差值即IBS的周期变化幅度(CVIB),并将其与心包IBS的比值作为心肌CVIB的校正值(CVIB%).同时作心电图的比较对照.结果 当AMI超急性期组患者心电图还无典型变化时,心肌梗死部位的IBS值已明显大于正常人[(18.8±3.4)dB比(8.3±1.2)dB,P<0.01],而CVIB明显小于正常人[(6.3 ±0.7)dB比(7.6±1.1)dB,P<0.01].急性期组患者,其IBS明显高于正常人及患者本身非心肌梗死部位[(22.2±4.1)dB比(8.3±1.2)dB,(21.1±3.2)dB比(8.7 ±0.9)dB,P<0.01],而CVIB则明显低于正常人及患者本身非心肌梗死部位[(5.6±0.8)dB比(7.6±1.1)dB,P<0.05;(5.8±0.7)dB比(9.3±0.9)dB,P<0.01].且与心电图的变化完全一致.结论 心肌组织背向散射积分对临床上诊断AMI超急性期有很高的价值,并可判断病变心肌的范围和功能状况.     

Non-contrast second harmonic imaging improves interobserver agreement and accuracy of dobutamine stress echocardiography in patients with impaired image quality

OBJECTIVE: To examine the influence of second harmonic imaging during dobutamine echocardiography on regional endocardial visibility, interobserver agreement in the interpretation of wall motion abnormalities, and diagnostic accuracy in patients with reduced image quality. DESIGN: Blinded comparison. SETTING: Tertiary care centre. PATIENTS: 103 consecutive patients with suspected coronary artery disease and impaired transthoracic image quality (>/= 2 segments with poor endocardial delineation). METHODS: Fundamental and second harmonic imaging were performed at each stage of a dobutamine stress echocardiography. Coronary angiography was undertaken within three weeks of dobutamine echocardiography in 75 patients. MAIN OUTCOME MEASURES: Evaluation of regional endocardial visibility (scoring from 0 = poor to 2 = good) and of segmental wall motion abnormalities for both modalities separately. A second blinded examiner analysed 70 studies to determine interobserver agreement. RESULTS: Mean (SD) visibility score for all segments was 1.2 (0.4) using fundamental imaging and 1.7 (0.2) using second harmonic imaging at rest (p < 0.001), and 1.1 (0.4) v 1.6 (0.3), respectively, at peak dobutamine dose (p < 0.001). The average number of segments with poor endocardial visibility was lower for second harmonic than for fundamental imaging (0.6 (1.1) v 3.8 (2.6) at rest, p < 0.001; 0.9 (1.3) v 4.3 (2.9) at peak dose, p < 0.001). Improvement was most pronounced in all lateral and anterior segments. The kappa value for identical study interpretation increased from 0. 40 to 0.69 (p < 0.05). Sensitivity for the diagnosis of coronary artery disease was 64% using fundamental imaging versus 92% using harmonic imaging (p < 0.001), while specificity remained unchanged at 75% for both imaging modalities. CONCLUSIONS: Second harmonic imaging enhances endocardial visibility during dobutamine echocardiography. Consequently, interobserver agreement on stress echocardiography interpretation and diagnostic accuracy are significantly improved compared to fundamental imaging. Thus, in difficult to image patients, dobutamine echocardiography should be performed using second harmonic imaging.     

Ultrasonic integrated backscatter discloses intramyocardial hemorrhage in patients with acute myocardial infarction

BACKGROUND: It has been reported that intramyocardial hemorrhage (IH) can be detected by magnetic resonance imaging (MRI) and IH correlates with the poor prognosis of acute myocardial infarction (AMI). We examined whether integrated backscatter (IBS) can disclose IH in patients with AMI. We recorded IBS images in 34 patients with AMI who underwent coronary angioplasty within 12 hours of symptom onset. METHODS: We measured calibrated IBS (C-IB) and cyclic variation (CV) in the center of the risk area on the third day after reperfusion. C-IB was calculated as: average IBS value of risk area--average IBS value of intraventricular blood. MRI was performed within 3 days after reperfusion. Regional wall motion score index (RWMSI) was calculated as follows: sum of scores (0 - 4) in risk area/number of segments of risk area. We evaluated left ventricular function using RWMSI shortly and one month after reperfusion. RESULTS: RWMSI in the IH group (12 cases) was significantly higher than in the non-IH group (2.3+/-0.5 vs. 1.8+/-0.6: P<0.01) one month later, while RWMSI in both groups was almost the same shortly after reperfusion. The IH group showed a significantly higher value of C-IB than the non-IH group (18.6+/-2.0 vs. 16.0+/-1.4: P<0.01), while there were no significant differences in CV values between two groups. Using 17 as a cutoff value of C-IB, C-IB can detect IH with 92% sensitivity and 91% specificity. Using both CV and C-IB, however, IH can be detected more specifically. CONCLUSION: Ultrasonic IBS, especially C-IB, discloses intramyocardial hemorrhage in patients with reperfused AMI.     

Quantitative evaluation of myocardial perfusion in patients with revascularized myocardial infarction: comparison between intravenous myocardial contrast echocardiography and 99mTc-sestamibi single photon emission computed tomography.

AIMS: This two-center study compared quantitative segmental perfusion mapping by intravenous myocardial contrast echocardiography (ivMCE) and scintigraphy (SPECT) in patients in the subacute phase of myocardial infarction (AMI). METHODS AND RESULTS: Sixteen patients underwent ivMCE using 1:1 intermittent harmonic imaging 24 h after first AMI treated with PTCA and stenting. Apical contrast echocardiograms were obtained after the injections of Sonazoid. Baseline-corrected peak myocardial videointensity (bcPMVI) was determined automatically in 16 segments. Resting 99mTc-sestamibi SPECT was performed within one day after ivMCE. SPECT images were reoriented matching the ivMCE views, and divided into the same segments as in ivMCE, from which mean count rate values were obtained. After exclusion due to artifacts or attenuation, 208/256 (82%) segments remained for analysis. Normalized SPECT count rate and bcPMVI correlated linearly: bcPMVI = 1.237 x SPECT - 35; r = 0.74, p < 0.0001. The relation remained identical in subgroup analysis based on participating center, echocardiographic view, perfusion territory, infarct zone, or function. Using SPECT as reference, mean bcPMVI was 77+/-19% in normal segments, 53+/-29% in mild-moderate defects and 25+/-18% in severe defects (p<0.001 for all comparisons). CONCLUSION: The videointensity increase observed in quantitative ivMCE clearly correlated with SPECT tracer uptake. This further substantiates the use of ivMCE as a valid technique for myocardial perfusion imaging.     

Detection and clinical usefulness of a biphasic response during exercise echocardiography early after myocardial infarction

OBJECTIVE: The aim of this study was to determine the accuracy of exercise echocardiography (EE) for detecting infarct-related artery (IRA) stenosis and predicting functional recovery early after acute myocardial infarction (AMI). BACKGROUND: Dobutamine stress echocardiography is widely used for identifying jeopardized myocardium. The clinical usefulness of a biphasic response detected during EE has never been investigated. METHODS: A total of 114 consecutive patients with a first AMI and > or = 2 dyssynergic segments in the infarct-related territory underwent semi-supine continuous EE 6 +/- 2 days after AMI. Quantitative coronary angiography was performed in all patients after EE. A follow-up echocardiogram was obtained one month later. RESULTS: Ninety-seven patients had significant (> or = 50%) IRA stenosis, and 26 had multivessel disease. Residual ischemia was identified in 77 patients (biphasic response in 62 and worsening response in 15). The sensitivity and specificity of ischemia during EE for predicting IRA stenosis were 75% and 76%, respectively. The sensitivity of a biphasic response was higher than the sensitivity of a worsening response (61% vs. 14%, p < 0.0001). Wall motion abnormalities induced in other vascular territories were specific (97%) and moderately sensitive (62%) for the detection of multivessel disease. Functional recovery was observed in 75 patients. Two independent variables predicted contractile recovery: contractile reserve during EE (p < 0.0001) and elective angioplasty of the IRA (p = 0.002). A biphasic response, but not sustained improvement, predicted reversible dysfunction (73% vs. 9%, p < 0.0001). CONCLUSIONS: A biphasic response can be detected during exercise. Exercise echocardiography is an accurate tool for detecting IRA stenosis and predicting functional improvement early after AMI.     

NC100100, a new echo contrast agent for the assessment of myocardial perfusion--safety and comparison with technetium-99m sestamibi single-photon emission computed tomography in a randomized multicenter study

BACKGROUND AND HYPOTHESIS: Myocardial contrast echocardiography using second-generation agents has been proposed to study myocardial perfusion. A placebo-controlled, multicenter trial was conducted to evaluate the safety, optimal dose, and imaging mode for NC100100, a novel intravenous second-generation echo contrast agent, and to compare this technique with technetium-99m sestamibi (MIBI) single-photon emission computed tomography (SPECT). METHODS: In a placebo-controlled, multicenter trial, 203 patients with myocardial infarction > 5 days and < 1 year previously underwent rest SPECT and MCE. Fundamental and harmonic imaging modes combined with continuous and electrocardiogram-- (ECG) triggered intermittent imaging were used. Six dose groups (0.030, 0.100, and 0.300 microliter particles/kg body weight for fundamental imaging; and 0.006, 0.030, and 0.150 microliter particles/kg body weight for harmonic imaging) were tested. A saline group was also included. Safety was followed for 72 h after contrast injection. Myocardial perfusion by MCE was compared with myocardial rest perfusion imaging using MIBI as a tracer. RESULTS: NC100100 was well tolerated. No serious adverse events or deaths occurred. No clinically relevant changes in vital signs, laboratory parameters, and ECG recordings were noted. There was no significant difference between adverse events in the NC100100 (25.7%) and in the placebo group (17.9%, p = 0.3). Intermittent harmonic imaging using the intermediate dose was superior to all other modalities, allowing the assessment of perfusion in 76% of all segments. Eighty segments (96%) with normal perfusion by SPECT imaging also showed myocardial perfusion with MCE. However, a substantial percentage of segments (61-80%) with perfusion defects by SPECT imaging also showed opacification by MCE. This resulted in an overall agreement of 66-81% and a high specificity (80-96%), but in low sensitivity (20-39%) of MCE for the detection of perfusion defects. CONCLUSION: NC100100 is safe in patients with myocardial infarction. Intermittent harmonic imaging with a dose of 0.03 microliter particles/kg body weight can be proposed as the best imaging protocol. Myocardial contrast echocardiography with NC 100100 provides perfusion information in approximately 76% of segments and results in myocardial opacification in the vast majority of segments with normal perfusion as assessed by SPECT. Although the discrepancies between MCE and SPECT with regard to the definition of perfusion defects requires further investigation, MCE with NC 100100 is a promising technique for the noninvasive assessment of myocardial perfusion.     

Usefulness of myocardial contrast echocardiography in predicting collateral blood flow in the presence of a persistently occluded acute myocardial infarction-related coronary artery

Adequate collateral blood flow at rest can sustain myocardial viability despite persistent occlusion of the infarct-related artery (IRA) in acute myocardial infarction (AMI). This has therapeutic and prognostic implications. Studies addressing the value of intravenous myocardial contrast echocardiography (MCE) to detect collateral blood flow after AMI in humans are limited. Accordingly, 70 consecutive patients with AMI underwent low-power intravenous MCE using a Sonovue infusion 7 to 10 days after thrombolysis. Myocardial perfusion detected by MCE was analyzed (qualitatively and quantitatively) in the akinetic segments in 20 patients (29%) with an occluded IRA who subsequently underwent revascularization. Contractile reserve, which is a marker of myocardial viability, was assessed with low-dose dobutamine 12 weeks after mechanical revascularization. Of the 102 akinetic segments (32%), 37 (36%) showed contractile reserve. Contractile reserve was present in 24 of the 29 segments (83%) with homogenous contrast opacification and absent in 60 of the 73 segments (82%) with reduced/absent opacification. Quantitative peak contrast intensity, microbubble velocity, and myocardial blood flow were significantly higher (p <0.0001) in the segments with contractile reserve than in those without contractile reserve. Multiple logistic regression analysis using electrocardiographic, biochemical, and myocardial contrast echocardiographic markers of collateral blood flow showed that MCE (odds ratio 26.0, 95% confidence interval 6.3 to 108.0, p <0.001) was the only independent predictor of collateral blood flow as demonstrated by the presence of contractile reserve. MCE may thus be used as a reliable bedside technique for the accurate evaluation of collateral blood flow in the presence of an occluded IRA after AMI.     

急诊PCI术中再灌注心律失常的研究

目的探讨急性心肌梗死患者急诊行经皮冠状动脉介入术(PCI)中再灌注心律失常(RA)的临床特点。方法回顾性分析125例急性心肌梗死且急诊行PCI术治疗患者的临床资料。观察分析再灌注心律失常与梗死相关动脉(IRA)开通所需时间、IRA是否完全闭塞及梗死面积大小的之间的关系。结果 125例患者中85例发生RA(68%)。梗死6h内开通冠状动脉者再灌注心律失常发生率明显高于6～12h开通者(p<0.05)。完全闭塞组RA发生率总体发生率均显著高于次全闭塞组RA发生率(p<0.05)。广泛前壁心肌梗死与局限性心肌梗死RA的发生率无统计学差异(p>0.05)。结论 AMI患者直接PCI后RA发病率及严重程度与IRA病变程度、发病至开通IRA时间明确相关,与梗死面积无关。     

Second harmonic imaging improves sensitivity of dobutamine stress echocardiography for the diagnosis of coronary artery disease.

OBJECTIVE: Our purpose was to assess the value of second harmonic imaging compared with fundamental imaging for the diagnosis of coronary artery disease during dobutamine stress echocardiography. PATIENTS AND METHODS: Sixty-four patients underwent dobutamine stress echocardiography with both fundamental imaging and second harmonic imaging. Coronary angiography was performed within 3 months. Ischemia was defined as new or worsening wall motion abnormalities in > or = 1 segment during dobutamine stress echocardiography. Coronary artery disease was defined as a > or = 70% luminal diameter stenosis in > or = 1 coronary artery by coronary angiography. RESULTS: There was a higher prevalence of segments with invisible border with fundamental compared with second harmonic imaging both at rest (11% vs 8%, P < .05) and at peak stress (17% vs 10%, P < .001). Significant coronary artery disease was present in 49 (77%) patients. The sensitivity of dobutamine stress echocardiography for detection of coronary artery disease by fundamental and second harmonic imaging was, respectively, 78% and 94% (P < .05), whereas specificity was similar (73% vs 73%). Second harmonic imaging had a particularly higher sensitivity for the diagnosis of 1-vessel disease (93% vs 50%, P < .05). CONCLUSION: The use of second harmonic imaging improves the sensitivity of dobutamine stress echocardiography for the diagnosis of coronary artery disease compared with fundamental imaging, particularly for 1-vessel coronary artery disease, whereas specificity remains unchanged.     

Accuracy of dipyridamole myocardial contrast echocardiography for the detection of residual stenosis of the infarct-related artery and multivessel disease early after acute myocardial infarction

OBJECTIVES: We aimed to evaluate the ability of vasodilator myocardial contrast echocardiography (MCE) to detect significant infarct-related artery (IRA) stenosis and multivessel disease (MVD) after thrombolysis. BACKGROUND: The detection of residual IRA stenosis subtending significant viable myocardium and the identification of MVD may help to triage patients who may benefit from mechanical revascularization after acute myocardial infarction (AMI) and thrombolysis. METHODS: Patients with AMI underwent low-power MCE at rest and after dipyridamole stress during SonoVue infusion seven to 10 days after thrombolysis. RESULTS: Of the 73 patients, 61 demonstrated significant myocardial viability, of whom 57 (93%) showed significant IRA stenosis. Sensitivities to detect >50% IRA stenosis and MVD were 88% and 72%, respectively. The accuracy of detecting significant coronary stenosis in the anterior (left anterior descending coronary artery) versus inferoposterior (right coronary artery/left circumflex artery) circulation was similar for both IRA (85% vs. 91%) and remote territories (91% vs. 81%). Quantitative peak contrast intensity (p = 0.02), microbubble velocity (p = 0.0001), and myocardial blood flow (p < 0.0001) were significantly lower in patients with significant coronary stenosis during dipyridamole compared with rest. Only beta reserve discriminated various grades of coronary stenosis. CONCLUSIONS: Use of MCE accurately predicted significant IRA stenosis and MVD after thrombolysis. This information is valuable for identifying patients who may benefit from mechanical revascularization.     

Magnetic resonance imaging during acute myocardial infarction

Experimental canine studies have demonstrated the potential of magnetic resonance imaging (MRI) for detecting and characterizing acute myocardial infarction (AMI) in humans. Accordingly, electrocardiographic-gated spin-echo MR images of the left ventricular short axis were obtained in 34 patients a mean of 11 +/- 6 days (range 3 to 30) after AMI. This imaging technique allowed division of the left ventricle into segments corresponding to the left ventricular segments on angiography. Patients were separated into 2 groups; the first 16 patients (group I) were examined using a variety of imaging techniques. Information derived from this experience resulted in a standard imaging protocol and development of criteria for the presence of AMI. The imaging protocol and interpretation criteria were used in the assessment of a subsequent group of 18 patients (group II). Of the 14 patients in group II with satisfactory image quality, all showed an increase in myocardial signal intensity consistent with an AMI. In addition, the anterior or inferior location of the abnormal MR segments corresponded to the electrocardiographic infarct location. MR segments showing increased signal intensity corresponded with severely hypokinetic or akinetic segments on the left ventriculogram in 8 patients having both procedures. In a group of volunteers who underwent imaging and whose images were interpreted in the same manner as those of the patients with AMI, 1 of 9 subjects had regional variation in myocardial signal intensity compatible with an AMI. In summary, AMI is readily detected, located and characterized by electrocardiographic-gated MRI. These findings suggest that MRI techniques may have a role in the evaluation of AMI in humans.     

持续监测ST段对评估急性心肌梗死早期梗死相关动脉动态变化的意义

目的 持续监测ST段变化评估急性心肌梗死（AMI）早期梗死相关动脉（IRA）动态变化的意义。方法 对发病≤6h的55例（男40例,女15例,年龄39－80岁）AMI患进行动态心电图监测,持续观察24hST段变化并与冠状动脉造影结果作对照。结果 （1）IRA未开通ST段持续抬高并伴有逐渐下降趋势.(2)溶栓疗法和直接经皮冠状动脉腔内形成术成功后ST段迅速下降并保持相对稳定。（3）所有患24h内均见有间断的ST段抬高和下降的波动性变化,尤其多见于溶栓成功早期。结论 AMI发病早期IBA处于动态的开放－关闭状态,持续监测ST段可较全面反应IRA变化。     

Prediction of functional recovery of viable myocardium after delayed revascularization in postinfarction patients: accuracy of dobutamine stress echocardiography and influence of long-term vessel patency.

OBJECTIVES: We sought to evaluate dobutamine stress echocardiography (DSE) for predicting recovery of viable myocardium after revascularization with cineangiography as a gold standard for left ventricular (LV) function. We studied the influence of late vessel reocclusion on regional LV function. BACKGROUND: Dobutamine stress echocardiography is a well established evaluation method for myocardial viability assessment. In previous studies the reference method for assessing LV recovery was echocardiography, long-term vessel patency has not been systematically addressed. METHODS: Sixty-eight patients with a first acute myocardial infarction (AMI) and residual stenosis of the infarct related artery (IRA) underwent DSE (mean +/- standard deviation) 21 +/- 12 days after AMI to evaluate myocardial viability. Revascularization of the IRA was performed in 54 patients by angioplasty (n = 43) or bypass grafting (n = 11). Coronary angiography and LV cineangiography were repeated at four months to assess LV function and IRA patency. RESULTS: Sensitivity and specificity of DSE for predicting myocardial recovery after revascularization were 83% and 82%. In the case of late IRA patency, specificity increased to 95%, whereas sensitivity remained unchanged. In the 16 patients with myocardial viability and late IRA patency, echocardiographic wall motion score index decreased after revascularization from 1.83 +/- 0.15 to 1.36 +/- 0.17 (p = 0.0001), and left ventricular ejection fraction (LVEF) increased from 0.52 +/- 0.06 to 0.57 +/- 0.06 (p = 0.0004), whereas in five patients, reocclusion of the IRA prevented improvement of segmental or global LV function despite initially viable myocardium. CONCLUSIONS: Dobutamine stress echocardiography is reliable to predict recovery of viable myocardium after revascularization in postinfarction patients. Late reocclusion of the IRA may prevent LV recovery and influence the accuracy of DSE.     

易化的经皮冠脉介入治疗——急性心肌梗死治疗新策略

急性心肌梗死再灌注治疗的方法主要包括溶栓和紧急经皮冠脉介入治疗,其中溶栓治疗简单易行,但再灌注不充分,并且再闭塞率高;而直接经皮冠脉介入治疗,可以恢复心外膜血管的血流,血管的开通率高,但是只有在有条件的医院才能进行,而对于急性心肌梗死来讲,血管开通的时间是最重要的,因此,人们试图通过将溶栓治疗和经皮冠脉介入治疗联合应用来发挥各自的优势,尽量减少缺陷来尽快恢复心脏血流供给,也就是采用易化经皮冠脉介入治疗的方法来治疗急性ST段抬高心肌梗死,从而获得梗死相关动脉更早的开通和更高的开通率。     

Contrast and harmonic imaging improves accuracy and efficiency of novice readers for dobutamine stress echocardiography

BACKGROUND: Newer contrast agents as well as tissue harmonic imaging enhance left ventricular (LV) endocardial border delineation, and therefore, improve LV wall-motion analysis. Interpretation of dobutamine stress echocardiography is observer-dependent and requires experience. This study was performed to evaluate whether these new imaging modalities would improve endocardial visualization and enhance accuracy and efficiency of the inexperienced reader interpreting dobutamine stress echocardiography. METHODS AND RESULTS: Twenty-nine consecutive patients with known or suspected coronary artery disease underwent dobutamine stress echocardiography. Both fundamental (2.5 MHZ) and harmonic (1.7 and 3.5 MHZ) mode images were obtained in four standard views at rest and at peak stress during a standard dobutamine infusion stress protocol. Following the noncontrast images, Optison was administered intravenously in bolus (0.5-3.0 ml), and fundamental and harmonic images were obtained. The dobutamine echocardiography studies were reviewed by one experienced and one inexperienced echocardiographer. LV segments were graded for image quality and function. Time for interpretation also was recorded. Contrast with harmonic imaging improved the diagnostic concordance of the novice reader to the expert reader by 7.1%, 7.5%, and 12.6% (P < 0.001) as compared with harmonic imaging, fundamental imaging, and fundamental imaging with contrast, respectively. For the novice reader, reading time was reduced by 47%, 55%, and 58% (P < 0.005) as compared with the time needed for fundamental, fundamental contrast, and harmonic modes, respectively. With harmonic imaging, the image quality score was 4.6% higher (P < 0.001) than for fundamental imaging. Image quality scores were not significantly different for noncontrast and contrast images. CONCLUSION: Harmonic imaging with contrast significantly improves the accuracy and efficiency of the novice dobutamine stress echocardiography reader. The use of harmonic imaging reduces the frequency of nondiagnostic wall segments.     

Contrast echocardiography accurately predicts myocardial perfusion before angiography during acute myocardial infarction

OBJECTIVES: To determine whether myocardial contrast echocardiography (MCE) can quickly and accurately assess myocardial perfusion and infarct-related artery (IRA) patency before emergency angiography during acute myocardial infarction (AMI). BACKGROUND: Despite encouraging experimental and clinical studies, the reliability and practicality of MCE in predicting IRA patency during AMI before angiography has not been proven. METHODS: Two-dimensional echocardiography and MCE were performed in 51 patients with AMI just before emergency angiography. With knowledge of the electrocardiogram findings and regional wall motion, myocardial perfusion was assessed to predict IRA patency. RESULTS: Myocardial perfusion studies were adequate for interpretation in 40 patients. An occluded IRA was predicted in 28 patients; the artery was occluded in 22 patients, and six patients had Thrombolysis In Myocardial Infarction (TIMI) grade 2 flow or less. A patent IRA was predicted in 12 patients; eight patients had TIMI grade 3 flow, one patient had TIMI grade 2 flow and the IRA was occluded in three patients. In one of the three patients, the appropriate view was not obtained. In another patient, collateral flow was adequate for near-normal regional wall motion, and in the last, the findings suggested reperfusion of the proximal artery with distal embolic occlusion. Taken together, MCE accurately predicted either TIMI grade 2 flow or less, or TIMI grade 3 flow in 36 of 40 patients. Sensitivity was 87.5%, specificity and positive predictive value were 100% and negative predictive power was 66.7% (P<0.001). CONCLUSIONS: MCE, together with the electrocardiogram and regional wall motion, can be used to quickly and reliably predict IRA patency early during AMI and may be useful to facilitate a management strategy.     

Improved identification of viable myocardium using second harmonic imaging during dobutamine stress echocardiography

OBJECTIVE—To determine whether, compared with fundamental imaging, second harmonic imaging can improve the accuracy of dobutamine stress echocardiography for identifying viable myocardium, using nuclear imaging as a reference.
PATIENTS—30 patients with chronic left ventricular dysfunction (mean (SD) age, 60 (8) years; 22 men).
METHODS—Dobutamine stress echocardiography was carried out in all patients using both fundamental and second harmonic imaging. All patients underwent dual isotope simultaneous acquisition single photon emission computed tomography (DISA-SPECT) with ^99mtechnetium-tetrofosmin/¹⁸F-fluorodeoxyglucose on a separate day. Myocardial viability was considered present by dobutamine stress echocardiography when segments with severe dysfunction showed a biphasic sustained improvement or an ischaemic response. Viability criteria on DISA-SPECT were normal or mildly reduced perfusion and metabolism, or perfusion/metabolism mismatch.
RESULTS—Using fundamental imaging, 330 segments showed severe dysfunction at baseline; 144 (44%) were considered viable. The agreement between dobutamine stress echocardiography by fundamental imaging and DISA-SPECT was 78%, κ = 0.56. Using second harmonic imaging, 288 segments showed severe dysfunction; 138 (48%) were viable. The agreement between dobutamine stress echocardiography and DISA-SPECT was significantly better when second harmonic imaging was used (89%, κ = 0.77, p = 0.001 v fundamental imaging).
CONCLUSIONS—Second harmonic imaging applied during dobutamine stress echocardiography increases the agreement with DISA-SPECT for detecting myocardial viability.


Keywords: dobutamine stress echocardiography; second harmonic imaging; ¹⁸F-fluorodeoxyglucose imaging; myocardial viability     

Long-term beneficial effect of infarct-related artery patency in acute anterior myocardial infarction in patients with poor myocardial viability in the region-at-risk.

BACKGROUND: Several studies have demonstrated the benefit of the patency of infarct-related artery (IRA) in acute myocardial infarction (AMI). However those studies have not been concerned with myocardial viability in the region-at-risk. In the present study the effect of the patency of IRA was investigated in the setting of anterior AMI with poor viable myocardium in the risk region. METHODS AND RESULTS: From 1993 to 1996 patients with a first time anterior AMI and poor viable myocardium in the region-at-risk at 1 month after onset were identified and enrolled. Patients with a totally occluded IRA were included in the Non-Open group (n=44), and patients with a reperfused IRA were included in the Open group (n=49). At 5 years after onset, left ventricular function was better preserved in the Open group than in the Non-Open group (p<0.05). Kaplan-Meier survival curves for cardiac mortality and event-free survival curves revealed poor prognoses in the Non-Open group over a 5-year period (p<0.05, respectively). The advantages of a patent IRA were further seen in health-related quality-of-life outcomes (p<0.05). CONCLUSIONS: Even in patients with poor myocardial viability after an anterior AMI, the patency of the IRA is strongly associated with improved long-term survival, independent of residual myocardium viability.     

静脉心肌声学造影在心肌梗死再灌注治疗及血管成形术中的应用

目的 :探讨静脉心肌声学造影 (MCE)评估急性心肌梗死再灌注治疗效果、冠状动脉介入治疗疗效以及预测存活心肌的价值。方法 :采用HP 5 5 0 0型超声心动仪 ,综合应用二次谐波、间歇成像和能量多普勒成像并采用高能量的超声波发射 ,对3 5例患者静脉注射利声显行MCE ,并行冠状动脉造影进行对比研究。结果 :3 5例患者完成MCE。 17例急性心肌梗死 (AMI)患者中 ,再灌注治疗患者MCE图象评分与保守治疗患者之间差异有显著性 (P <0 0 5 ) ;19例心肌梗死患者行介入治疗 ,共 63个血管重建术相关的心肌节段 ,在心肌梗死急性期 ,介入治疗前MCE显示心肌有灌注 ( 1分或 0 5分 )的心肌节段存活性及术后灌注改善的可能性显著高于MCE无灌注 ( 0分 )的心肌节段 (P <0 0 5 ) ,在心肌梗死陈旧期 ,介入治疗前MCE显示心肌灌注良好 ( 1分 )的心肌节段的存活性及术后灌注改善的可能性显著高于MCE灌注不佳 ( 0分或 0 5分 )的心肌节段 (P <0 0 5 )。结论 :结合多种成像技术 ,利声显可行静脉MCE。MCE可以评估AMI再灌注治疗的疗效 ,评估介入治疗的疗效并判断心肌存活性。     

老年急性心肌梗死后梗死相关动脉再灌注对QT离散度的影响

目的了解老年急性心肌梗死(AMI)后梗死相关动脉(IRA)早期静脉溶栓再灌注或冠状动脉内支架置入术对QT离散度(QTd)的影响。方法对58例老年AMI患者(AMI组)予以静脉内溶栓,溶栓后选择性冠状动脉造影,对判定为心肌梗死溶栓试验性疗法(TIMI)2级以下者,部分行冠状动脉内支架置入术。溶栓前后测量分析QTd,并与48例冠状动脉造影正常的老年人(对照组)和50例健康体检非老年患者(非老年组)进行对照。结果AMI组溶栓前与对照组和非老年组间QTd有显著性差异(P<0.01);静脉溶栓后冠状动脉造影显示IRA血流达到TIMI 2~3级者,溶栓后2 h QTd显著降低,而IRA未开通者其QTd始终保持较高水平。16例溶栓前有室性心律失常者其QTd明显高于无心律失常者(P<0.05),结论IRA早期再灌注可使QTd显著降低,可减少恶性心律失常的发生。