小剂量腺苷负荷超声心动图试验与双核素心肌显像检测急性心肌梗死后患者存活心肌比较

目的:比较小剂量腺苷负荷超声心动图试验(LDASE)与99mTc-甲氧基异丁腈(MIBI)/18F-脱氧葡萄糖(FDG)双核素同时采集法(DISA)单光子发射断层显像(SPECT)对急性心肌梗死(AMI)患者早期存活心肌检出的准确性.方法:对36例AMI患者于发病后3～10 d内行LDASE与DISA-SPECT.所有患者在LDASE前后接受经皮冠状动脉介入治疗术.AMI后3个月随访二维超声心动图,以局部室壁运动改善作为心肌存活的金标准,比较2种方法检测存活心肌的敏感性和特异性.结果:LDASE检出存活心肌敏感性为90.3%,特异性为80.8%,阳性预测值与阴性预测值分别为84.8%和87.5%,准确性为86.0%;DISA-SPECT检出存活心肌敏感性81.2%,特异性78.3%,阳性预测值81.1%,阴性预测值83.1%,准确性80.2%.2种方法对运动异常节段存活心肌检出一致性为72.6%,差异无统计学意义.结论:对AMI后患者,LDASE与DISA-SPECT均为检出存活心肌较敏感和特异的技术.     

药物负荷超声心动图与同位素双核素SPECT心肌显像对比检测冠心病左心室收缩功能严重减低患者存活心肌

目的比较99mTc-甲氧基异丁腈(MIBI)/18F-脱氧葡萄糖(FDG)双核素同时采集法(DISA)SPECT心肌显像和药物负荷二维超声心动图(2DE)试验识别冠心病左心室收缩功能严重减低患者(左室射血分数,LVEF≤45%)存活心肌的准确性.方法陈旧性心肌梗死伴左心室收缩功能严重减低患者26例,平均LVEF38.6%±4.9%,在一周内分别进行小剂量多巴酚丁胺(Dob)10μg·kg-1·min-1、异舒吉合用Dob5μg·kg-1·min-1的2DE试验,以及DISA SPECT心肌显像.所有患者在冠状动脉血运重建(CRV)术后6.8±2.9月完成了2DE复查.采用16节段半定量法分别分析图像,以CRV术后收缩功能改善节段为存活标准,比较两种方法检测存活心肌的敏感性、特异性和准确性.结果26例患者的272个运动异常节段中,术后156个(57.4%)有收缩运动改善.DISASPECT检测出72.4%(134/254)存活心肌节段,显著高于术后心肌收缩功能改善率(P＜0.001).药物负荷2DE试验的存活心肌检出率,小剂量Dob10μg·kg-1·min-12DE为65.5%(163/249),异舒吉-Dob5μg·kg-1·min-12DE为65.7%(176/268),均与术后心肌收缩功能改善率一致(P均＞0.05).DISA SPECT检测存活心肌的敏感性、特异性和准确性分别为93%,55%和76.8%;Dob10μg·kg-1·min-12DE的分别为88.6%,64.2%和77.9%,均与DISA SPECT相当(P均＞0.05).异舒吉-Dob5μg2DE的检测效果已达Dob10μg·kg-1·min-12DE水平,敏感性和准确性(91.4%和81.4%)均与DISA SPECT相当(P均＞0.05),特异性(68.1%)还较之略高(P＜0.05).结论检测冠心病左心室收缩功能严重减低患者存活心肌,DISA SPECT的敏感性高,特异性偏低,准确性较好;小剂量Dob10pμg·kg-1·min-1 2DE的检测准确性、敏感性和特异性均与之相当.异舒吉-Dob5μg·kg-1·min-12DE的检测敏感性和准确性均达Dob10μg·kg-1·min-12DE水平,并与DISA SPECT相当,特异性还较同位素的略高.     

低剂量多巴酚丁胺超声心动图和心电图ST段抬高预测血管重建术后存活心肌

目的采用低剂量多巴酚丁胺超声心动图(LDDE)和负荷心电图ST段抬高评价梗塞心肌节段于血管重建术前后的存活心肌.方法心肌梗死患者35例,于术前行低剂量多巴酚丁胺超声心动图和负荷心电图检查,术后一个月重复基础超声心动图检查.采用16节段和4分法评估左室功能,在术前和术后随访时有1个或1个以上节段室壁运动评分≥1为功能改善.结果 35例心肌梗死患者, 术后有18例室壁运动改善.有14例患者在行低剂量多巴酚丁胺试验时出现ST段抬高,其中术后有11例室壁运动改善, ST段抬高预测术后室壁运动改善的敏感性和特异性分别为61%和82%.同样,在术前LDDE心肌收缩力储备阳性的16例患者中,术后有14例功能改善,则LDDE对术后室壁运动改善的敏感性和特异性分别为77%和88%.结合术前负荷试验ST段抬高和LDDE心肌收缩力储备阳性,对术后室壁运动改善的敏感性和特异性分别为61%和94%.结论负荷试验ST段抬高和LDDE均是检测存活心肌安全、易行及有价值的方法.     

在负荷多巴酚丁胺超声心动图中T波假正常化预测血管重建术后存活心肌

目的在负荷多巴酚丁胺超声心动图试验中，评估T波假正常化及收缩储备对存活心肌的检测价值。方法41例近期心肌梗死患者，于血管重建术前行低剂量多巴酚丁胺超声心动图(Low—Dose Dobutamine Echocardiography，LDDE)和负荷心电图检查，术后两个月重复静息超声心动图检查。采用16节段和4分法评估左室功能，在术前和术后随访时有1个或1个以上梗死节段室壁运动评分≥1为功能改善；T波的假正常化的定义为在≥2个梗死相关的心电图导联上T波由倒置变为直立。结果术后对所有心肌梗死患者进行了随访，其中有22例(54％)室壁运动改善，术前负荷超声心动图与负荷心电图总的符和率为71％，T波假正常化预测术后室壁运动改善的敏感性和特异性分别为77％和79％；LDDE预测术后室壁运动改善的敏感性和特异性分别为82％和84％；两种方法共同预测术后室壁运动改善的敏感性和特异性分别为64％和95％。结论负荷试验中T波假正常化和LDDE均是检测存活心肌安全、易行及有价值的方法。     

经静脉心肌声学造影评价心肌梗死后存活心肌的价值

目的　探讨经静脉心肌声学造影 (MCE)对心肌梗死后存活心肌的诊断价值。方法　 2 4例心肌梗死患者用二维超声评价室壁运动情况 ,同时经静脉进行MCE ,以 3个月后静态超声心动图左室心肌节段性运动改善为依据评价MCE对心肌梗死后存活心肌的诊断价值。结果　在 2 4例病人的 384个心肌节段中 ,运动异常节段 184个。在运动异常的 184个节段中 ,MCE1分 39段 ,0 5分 5 0段 ,0分 95段。 3个月复查 79个节段有运动改善 ,其中 39段来自MCE1分的心肌 ,4 0段来自MCE0 5分的心肌。MCE对预测心肌梗死后室壁运动改善的敏感性、特异性、阳性预测值、阴性预测值及准确率分别为 :10 0 %、89 7%、84 8%、10 0 %和 94 6 %。结论　MCE能比较准确地预测心肌梗死后心肌的存活性     

药物负荷试验核素心肌断层显像识别存活心肌

目的探讨药物多巴酚丁胺、硝酸异山梨酯负荷试验核素锝[^99mTc]甲氧异丁异腈（technetium [^99mTc] methoxy isobutyl isonitrile,^99mTc-MIBI）心肌断层显像识别存活心肌的价值。方法对48例陈旧性心肌梗死伴左心室收缩功能受损患者进行静息心肌^99mTc-MIBI心肌断层显像和多巴酚丁胺、硝酸异山梨酯负荷试验^99mTc-MIBI心肌断层显像,用半定量的方法将^99mTc-MIBI摄取进行评分,区分存活心肌和非存活心肌。结果^99mTc-MIBI显像判定,经皮冠状动脉介入术前存活心肌节段有279个．非存活心肌节段235个;经多巴酚丁胺加硝酸异山梨酯负荷后,心肌显像改善：轻度稀疏节段9个、中度稀疏节段24个、严重稀疏或缺损节段10个,共计43个节段显像改善,评分减少1分以上,存活心肌节段313个,非存活心肌节段201个。两组差异有统计学意义（P〈0．05）。经皮冠状动脉介入术后6个月,随访多巴酚丁胺加硝酸异山梨酯负荷后,心肌显像改善的32个节段发现,静息^99mTc-MIBI显像改善,另有8个受损节段正常化。多巴酚丁胺加硝酸异山梨酯负荷后心肌显像无变化的389个节段在经皮冠状动脉介入术后346个节段无变化。多巴酚丁胺加硝酸异山梨酯负荷心肌显像检测存活心肌的阳性预测值93％,阴性预测值89％。结论多巴酚丁胺加硝酸异山梨酯负荷后心肌显像对存活心肌的识别能够提高存活心肌的检出率。其阳性预测值和阴性预测值较好。     

小剂量多巴酚丁胺超声心动图联合心肌声学造影对心肌梗死后存活心肌的诊断价值

目的前瞻性评价小剂量多巴酚丁胺超声心动图(LDDE)联合心肌声学造影(MCE)对心肌梗死后存活心肌的诊断价值。方法对24例心肌梗死者进行静态MCE、LDDE及3个月后静态超声心动图随访分析。MCE和室壁运动均用16段划分法进行目测半定量计分。心肌造影计分(MCS)回声均匀性增强为1分,回声低淡不均匀为0.5分,缺损为0分。室壁运动计分(WMS)用常规计分法。结果随访时,运动改善的心肌节段中MCS1分占49.4%、0.5分占50.6%,对LDDE均有反应;运动无改善的节段MCS0.5分占9.5%,0分占90.5%,对LDDE有反应者占13.3%,无反应占86.7%。预测存活心肌的敏感性、特异性及准确率分别为LDDE86%、86.7%、86.4%;MCE100%、89.7%、94.6%;LDDE联合MCE86.1%、100%、94.0%。结论心肌微血管结构与功能的完善是心肌存活的基本条件。MCE灌注正常和低灌注,且对多巴酚丁胺有反应的心肌有收缩力储备;而对多巴酚丁胺无反应的低灌注或无灌注心肌则多不能恢复收缩功能。LDDE联合MCE能提高检测存活心肌的特异性及准确率。     

不同小剂量多巴酚丁胺超声心动图与18F-脱氧葡萄糖心肌代谢显像对比检测冠心病左心室收缩功能严重受损患者存活心肌

目的 :与18F 脱氧葡萄糖单光子发射计算机断层摄影术 (SPECT)心肌代谢显像对比 ,评价不同小剂量多巴酚丁胺超声心动图 ,检测冠心病左心室收缩功能严重受损患者存活心肌的准确性和安全性。方法 :冠心病心肌梗死伴左心室收缩功能严重受损 (平均左心室射血分数 0 3 8± 0 0 5 )的患者 3 3例 ,1周内分别进行不同小剂量多巴酚丁胺 [3、5、10 μg/(kg·min) ]超声心动图和99m锝 甲氧基异丁基、18F 脱氧葡萄糖SPECT心肌灌注及代谢显像。图像分析均采用 16节段半定量法。以18F 脱氧葡萄糖SPECT检测结果为标准 ,评价不同小剂量多巴酚丁胺超声心动图检测存活心肌的敏感性、特异性、准确性和安全性。结果 :3 3例患者的 3 65个运动异常节段中存活心肌检出率 :18F 脱氧葡萄糖SPECT心肌代谢显像检出的存活心肌节段为 67 4% ,多巴酚丁胺 3、5和 10 μg/(kg·min)分别为 3 8 9%、61 4%和 70 4%。多巴酚丁胺 3 μg/(kg·min)检出的存活心肌节段显著低于18F 脱氧葡萄糖SPECT心肌代谢显像检出的存活心肌节段 (P <0 0 0 1)。多巴酚丁胺 3、5、10μg/(kg·min)超声心动图检出存活心肌的敏感性分别为 5 1 6%、82 9%和 91 8% ,准确性分别为 63 6%、81 6%和87 8% ,均显著递增 (P <0 0 5～ 0 0 0 1) ;副作用发生率分别     

小剂量腺苷超声心动图试验检测急性心肌梗死后患者存活心肌

目的 评价小剂量腺苷超声心动图试验(LDAE)对急性心肌梗死早期存活心肌检出的准确性.方法 对36例急性心肌梗死患者于发病后3～10 d行剂量递增的LDAE(腺苷80、100和110μg·kg-1·min),所有患者在LDAE前后接受经皮冠状动脉介入术.采用17节段半定量分析法分析二维超声图像.心肌梗死后2～3个月随访二维超声,以局部室壁运动改善作为心肌存活标准,评价LDAE检测存活心肌的敏感性、特异性和小剂量腺苷对血液动力学的影响.结果 腺苷110μg·kg·min时与用药前比较,心率轻度增快[(78.1±10.9)次/min比(70.7±10.8)次/min,P<0.01],左室收缩末期容积减小[(20.1±9.3)ml比(30.4±1.9)ml,P<0.01]和射血分数升高(74.7%±9.8%比62.6%±10.4%,P<0.01).腺苷不良反应总发生率38.9%(14/36),但症状轻微.LDAE检出存活心肌的敏感性、特异性、诊断准确性、阳性预测值和阴性预测值分别为90.3%、80.8%、86.0%、84.8%和87.5%.腺苷剂量100μg·kg·min时敏感性(88.5%)和特异性(86.0%)好而不良反应无明显增加.结论 LDAE是检测急性心肌梗死后患者存活心肌的较好而安全的新方法 ,有较高的敏感性和特异性,腺苷剂量100μg·kg·min可作为LDAE进一步研究的推荐剂量.     

201Tl静息-再分布显像后行再注射心肌断层显像检测存活心肌的价值

为评价２０１Ｔｌ静息－再分布显像后行再注射显像检测存活心肌的价值,对２４例心肌梗死患者行２０１Ｔｌ静息－再分布－再注射显像。８例经皮穿刺腔内冠状动脉成形术（ＰＴＣＡ）的患者术前及术后２周～４周随访了超声心动图。结果显示２０１Ｔｌ静息显像有９７个心肌节段放射性摄取异常,其中４ｈ再分布显像有可逆性灌注缺损３１个节段,再注射显像均为可逆性缺损;再分布显像为不可逆性灌注缺损的６６个节段,其中９个节段（１３．６４％）再注射显像表现为再充填。２０１Ｔｌ静息－再分布显像和２０１Ｔｌ静息－再分布－再注射显像预测ＰＴＣＡ术后心肌灌注改善的阳性预测值分别为７７．７８％和８０．９５％,阴性预测值分别为７７．７８％和９３．３３％。２０１Ｔｌ静息－再分布显像和２０１Ｔｌ静息－再分布－再注射显像预测存活心肌的准确性分别为７７．７８％和８６．１１％。因此２０１Ｔｌ静息－再分布显像后行再注射显像可提高对部分存活心肌的检出。这种显像方案尤其适合于伴严重左室功能障碍和运动试验有禁忌证的患者的存活心肌的评价。     

低剂量多巴酚丁胺超声负荷试验与左心室造影术对不稳定型心绞痛合并心功能不全患者存活心肌检测的对比研究

目的　探讨低剂量多巴酚丁胺左心室造影术 (L DDV)对不稳定型心绞痛合并左心功能不全患者存活心肌检测的可靠性。方法　选择 5 2例有不稳定型心绞痛病史 ,心功能在 - 级间 ,超声心动图有节段性室壁运动异常 ,左心室射血分数 (L VEF)在 35 %～ 4 0 %的患者 ,分别用低剂量多巴酚丁胺超声负荷试验 (L DDE)及低剂量多巴酚丁胺左心室造影 (L DDV)技术评价存活心肌后进行血运重建术 (PCI或 CABG)。于术后半年复查超声心动图及左心室造影 ,比较两种方法检测存活心肌的准确性、敏感性及特异性。结果　 L DDE技术检测存活心肌的敏感性为6 7.1% ,特异性为 76 % ,准确性为 6 8%。 L DDV技术检测存活心肌的敏感性为 6 8% ,特异性为 76 % ,准确性为71%。两组间差异无显著性 (P>0 .0 5 )。结论　 L DDV技术识别不稳定型心绞痛合并心功能不全者存活心肌与L DDE技术相比 ,同样具有较高可靠性     

Tissue velocity imaging during dobutamine stimulation for assessment of myocardial viability: segmental analysis in patients after myocardial infarction

BACKGROUND: Dobutamine stress echocardiography (DSE) is an established method for the detection of viable myocardium, but evaluation of this method is subjective. Tissue velocity Imaging (TVI) allows quantitative analysis of regional myocardial wall motion by assessment of systolic myocardial velocities. The aim of this study was to evaluate the diagnostic value of DSE and TVI for detection of viable myocardium. METHODS: In 56 patients (58+/-12 years) with previous myocardial infarction (130+/-42 days, mean ejection fraction 42+/-15%) low-dose DSE was combined with analysis of peak systolic myocardial velocities (Vpeak) by TVI for assessment of myocardial viability. As reference served a follow-up echocardiography after successful revascularization (mean 91+/-3 days). RESULTS: Of a total of 896 segments 200 showed abnormal wall motion (31 mildly hypokinetic, 50 severely hypokinetic, 115 akinetic, 4 dyskinetic). In 125 of these 200 segments regional improvement of regional wall motion was observed (62.5% viable). An increase of Vpeak>1 cm/s during dobutamine stimulation allowed the identification of viable myocardium with a sensitivity of 82% and a specificity 82% (DSE: 77% and 80%). By receiver operating characteristic (ROC) curve analysis, a cut-off value of 1.0 cm/s was the best parameter to differ viable from nonviable myocardium (area under the curve 0.85; p<0.01; 95% CI 0.79 to 0.90). Improvement of global ejection fraction after revascularization (47+/-13%, p=0.11) corresponded with three TVI viable segments with a sensitivity of 92% and a specificity of 89% (p=0.012). CONCLUSIONS: TVI allows the identification of viable myocardium during dobutamine stimulation and enables a quantitative interpretation of DSE.     

小剂量多巴酚丁胺超声心动图与硝酸甘油介入~(99m)Tc-MIBI的心肌灌注显像估测存活心肌

目的　探讨小剂量多巴酚丁胺超声心动图 (LDDE)与含服硝酸甘油 (NTG)介入99mTc 甲氧基异丁基异睛 (MIBI)的心肌灌注显像在心肌存活估测中的价值。方法　对 17例心肌梗死患者分别行静息 NTG介入99mTc MIBI和小剂量多巴酚丁胺超声心动图的检查 ,经皮冠状动脉腔内成形术或冠状动脉旁路移植术后一个月重复基础超声心动检查 ,并进行对比分析。结果　 17例患者于基础超声心动检查 ,共有 94个心肌节段运动异常 ,在其中 5 0个低动力心肌节段中 ,两种方法一致性节段 2 9个 (5 8% ,P >0 .0 5 ) ;在 44个无动力心肌节段中两种方法一致性节段 16个 (36 % ,P<0 .0 5 )。两种方法对低动力心肌节段功能恢复的预测差异无显著性意义 (P>0 .0 5 ) ;而对无动力心肌节段 ,LDDE较NTG介入 99m　Tc MIBI心肌灌注显像有较高的特异性 (90 .9%vs 6 4.7% ,P <0 .0 5 )和较低的敏感性 (6 3.6 %vs88.9% ,P <0 .0 5 )。对整个运动障碍节段功能恢复的预测 ,LDDE较NTG介入99mTc MIBI心肌灌注显像有较高的特异性 (87.2 %vs 6 8.2 % ,P <0 .0 5 )。结论　两种方法对低动力心肌节段的预测有良好的一致性 ,LDDE对整个运动障碍节段功能恢复的预测有较高的特异性。     

Comparison of low-dose dobutamine echocardiography and thallium-201 reinjection for the determination of myocardial viability in the early post myocardial infarction period

OBJECTIVE: Determination of viability in the infarction zone in the early post Ml period is an important parameter in clinical decision making. METHODS: In an attempt to compare the places of low-dose dobutamine echocardiography (LDDE) and thallium-201 reinjection SPECT (TI-SPECT) in the determination of viability in dyssynergic myocardial segments, 17 patients (mean age: 54.6 +/- 12.8 years, 16 male, 1 female) with a recent myocardial infarction and an uneventful early clinical course underwent both tests within 5-13 days of infarction. The 16-segment model was utilised to evaluate the left ventricular wall motion and each segment was graded as 1) normokinetic, 2) hypokinetic, 3) akinetic and 4) dyskinetic or aneurysmal on a 4-scale basis. A dyssynergic segment of myocardium was considered to be viable by LDDE if it showed an improvement in wall motion of at least one grade with low-dose dobutamine infusion (10 microg/kg/min). On the other hand, mild to moderate (< 50%) fixed perfusion defects and reversible (at least a 10% improvement in perfusion on either redistribution or reinjection images) severe (50% or more) perfusion defects were considered positive for viability by TI-SPECT. RESULTS: Of the 76 segments with resting dyssynergy (10 dyskinetic/aneurysmal, 33 akinetic, 33 hypokinetic), 51 (67%) were shown to be viable by LDDE and 61 (80%) by TI-SPECT. There was an agreement of 76% (p = 0.03, K = 0.63) between the two methods. CONCLUSION: This study disclosed a moderate degree of agreement between LDDE and TI-SPECT for the determination of viability in dyssynergic myocardial segments in the early post-myocardial infarction period.     

Low-level exercise echocardiography detects contractile reserve and predicts reversible dysfunction after acute myocardial infarction: comparison with low-dose dobutamine echocardiography.

OBJECTIVES: The aim of this study was to evaluate low-level exercise echocardiography (LLEE) in detecting contractile reserve and predicting functional improvement of akinetic myocardium early after acute myocardial infarction (AMI). BACKGROUND: Experimental and clinical studies have shown that low-dose dobutamine enhances contractile function of dyssynergic but viable myocardium in patients with recent AMI. We hypothesized that endogenous catecholamines produced during a LLEE test could serve as a myocardial stressor to elicit contractile reserve. METHODS: Fifty-two consecutive patients with first AMI and > or =2 akinetic segments in the infarct-related territory underwent 5 +/- 2 days after AMI low-dose dobutamine echocardiography (LDDE) (5, 10 and 15 microg/kg/min) and LLEE (25 W during 3 min on a supine bicycle, with continuous echocardiographic recording). Both tests were performed on the same day, in random order. Follow-up echocardiography was obtained one month later. Regional wall thickening was semi-quantitatively assessed using a 16-segment, 5-grade scale model. Contractile reserve was defined as improvement in wall thickening of > or =1 grade. RESULTS: Mean increase in heart rate during stress tests was 15 +/- 7 beats/min with LLEE and 13 +/- 6 beats/min with LDDE (p = NS). Contractile reserve was detected in 119 (55%) of 217 akinetic segments at LLEE and in 137 (63%) segments at LDDE. At follow-up study, functional improvement was identified in 139 (64%) segments. Sensitivity, specificity and positive and negative predictive values for predicting functional recovery were 81%, 92%, 95% and 73%, respectively, for LLEE, and 91%, 86%, 92% and 84%, respectively, for LDDE. Moreover, there was a good correlation between systolic wall thickening measured in the center of the dyssynergic area during stress tests and at follow-up study: r = 0.77, p < 0.001 with exercise testing and r = 0.73, p < 0.001 with dobutamine testing. CONCLUSIONS: Low-level exercise echocardiography provides a promising alternative to LDDE for identifying myocardial viability and predicting reversible dysfunction early after AMI.     

Detecting viable myocardium and predicting functional improvement: comparisons of positron emission tomography, rest-redistribution thallium-201 single-photon emission computed tomography (SPECT), exercise thallium-201 reinjection SPECT, I-123 BMIPP SPECT and dobutamine stress echocardiography.

BACKGROUND: Low-dose dobutamine stress echocardiography (LDDE) has become a useful and safe method for identifying hibernating or stunned myocardium and for predicting improvement in wall motion after coronary revascularization. METHODS AND RESULTS: In the present study, fluorine-18 fluorodeoxyglucose positron emission tomography (FDG-PET), rest-redistribution thallium-201 ((201)Tl) single-photon emission computed tomography (RR-Tl SPECT), (123)I-15-(p-iodophenyl)-3-(R,S)-methyl pentadecanoic acid (BMIPP) and LDDE were performed in 30 patients with acute myocardial infarction (AMI) at 10+/-3 days after the onset of AMI. Also, exercise (201)Tl reinjection SPECT (RI-Tl SPECT) was performed at 14+/-2 days. Follow-up echocardiography was performed 5+/-3 months later in all patients after interventional therapy for the assessment of functional recovery. Of the 390 segments analyzed by echocardiography, 110 (28%) had abnormal wall motion. There were no significant differences between RR-Tl SPECT and LDDE in sensitivity, specificity, positive predictive value and negative predictive value using the chi(2)-test; however, in akinetic segments, there was a significant difference in sensitivity. Among FDG-PET, RI-Tl SPECT, BMIPP and LDDE, there were significant differences in 3 variables. In akinetic segments, LDDE is superior to RR-Tl SPECT in sensitivity and to FDG-PET in specificity. In hypokinetic segments, LDDE is superior to RI-Tl SPECT and BMIPP in sensitivity, and to FDG-PET and BMIPP in specificity. CONCLUSIONS: LDDE could detect functional recovery of viable myocardium in the early period of AMI and can be performed easily and safely.     

药物负荷超声心动图与双核素心肌显像对比检测存活心肌

目的　比较99mTc 甲氧基异丁腈(MIBI) /18F 脱氧葡萄糖(FDG)双核素同时采集法(DISA)单光子发射型断层显像(SPECT)和药物负荷二维超声心动图(2DE)试验,识别冠心病左心室收缩功能严重减低患者[左室射血分数(LVEF)≤45% ]存活心肌的准确性。方法　陈旧性心肌梗死患者26例,平均LVEF(38. 6±4 .9 )%,在一周内分别进行小剂量多巴酚丁胺10μg·kg-1·min-1(Dob10μg)、亚硝酸异山梨酯合用Dob5μg·kg-1·min-1 (ISDN Dob5μg)的2DE试验,以及DISASPECT心肌显像。所有患者在冠状动脉血管重建(CRV)术后(6 .8±2 .9)个月完成了2DE复查。采用16节段半定量法分别分析图像,以CRV术后收缩功能改善节段为存活标准,比较两种方法检测存活心肌的敏感性、特异性和准确性。结果　26例患者272个运动异常节段中,术后156个( 57. 4% )有收缩运动改善。DISASPECT检测出72 .4% (134 /254)存活心肌节段,显著高于术后实际改善率(P<0 .001)。Dob10μg2DE的存活心肌检出率为65 5% (163 /249 ),ISDN Dob5μg2DE的为65 .7%(176 /268),均与术后实际改善率一致(P均>0 .05)。DISASPECT检测存活心肌的敏感性、特异性和准确性分别为93%, 55%和76. 8%;Dob10μg2DE的分别为88 .6%, 64 .2%和77. 9%,两种方法检测效果相当(P均>0 .05)。ISDN Dob5μg     

Significance of dobutamine-induced changes in QT dispersion early after acute myocardial infarction.

This study sought to examine the effects of graded dobutamine infusion on QT dispersion early after acute myocardial infarction (AMI) and to investigate the relation of dobutamine-induced changes in QT dispersion to wall motion responses. Seventy-eight patients with a first AMI underwent dobutamine-atropine stress echocardiography 5 +/- 2 days after admission. Contractile reserve was identified in 45 patients and ischemic myocardium in 40. Sixteen patients had persistent akinesia. The best cut-off value of QT dispersion on the baseline electrocardiogram for predicting myocardial viability was 65 ms (sensitivity and specificity of 68%). Dobutamine infusion increased QT dispersion only in patients with viable myocardium (61 +/- 18 to 83 +/- 19 ms, p = 0.003) and/or ischemia (72 +/- 16 to 112 +/- 25 ms, p < 0.0001). No change was observed in patients with persistent akinesia (84 +/- 10 to 87 +/- 15 ms, p = NS). QT dispersion increased by 22 +/- 12 ms with administration of low-dose dobutamine in patients who had viable myocardium and by 47 +/- 21 ms with administration of low- to high-dose dobutamine in patients with ischemic myocardium. An increase in QT dispersion of > or = 20 ms from at rest to low-dose dobutamine infusion was associated with myocardial viability with a sensitivity of 78% and a specificity of 79%, whereas an increase in QT dispersion of > or = 10 ms from low- to high-dose dobutamine infusion predicted ischemic myocardium with a sensitivity of 85% and a specificity of 82%. In conclusion, (1) low QT dispersion on the baseline electrocardiogram is determined by the presence of viable myocardium, (2) a dobutamine-induced increase in QT dispersion is associated with viable and jeopardized myocardium, and (3) unchanged QT dispersion during dobutamine stress is a simple marker of extensive necrosis.     

Combined assessment of microvascular integrity and contractile reserve improves differentiation of stunning and necrosis after acute anterior wall myocardial infarction

OBJECTIVES: We sought to determine the relative accuracy of myocardial contrast echocardiography (MCE) and low-dose dobutamine echocardiography (LDDE) in predicting recovery of left ventricular (LV) function in patients with a recent anterior wall myocardial infarction (MI). BACKGROUND: Left ventricular dysfunction after acute MI may be secondary to myocardial stunning or necrosis. Myocardial contrast echocardiography allows real-time echocardiographic perfusion assessment from a venous injection of a fluorocarbon-based contrast agent. Although this technique is promising, it has not been compared with LDDE. METHODS: Forty-six patients underwent baseline wall motion assessment, MCE, and LDDE two days after admission, as well as follow-up echocardiography after a mean period of 53 days. RESULTS: Perfusion by MCE predicted recovery of segmental function with a sensitivity of 69%, specificity of 85%, positive predictive value of 74%, negative predictive value of 81%, and overall accuracy of 78%. Contractile reserve by LDDE predicted recovery of segmental function with a sensitivity of 50%, specificity of 88%, positive predictive value of 72%, negative predictive value of 73%, and overall accuracy of 73%. Concordant test results occurred in 74% of segments and further increased the overall accuracy to 85%. The mean wall motion score at follow-up was significantly better in perfused versus nonperfused segments (1.9 vs. 2.6, p < 0.0001) and in segments with contractile reserve, compared with segments lacking contractile reserve (1.9 vs. 2.5, p < 0.0001). CONCLUSION: Myocardial contrast echocardiography compares favorably with LDDE in predicting recovery of regional LV dysfunction after acute anterior wall MI. Concordant contractile reserve and myocardial perfusion results further enhance the diagnostic accuracy.