小剂量多巴酚丁胺超声心动图评价急性心肌梗死存活心肌的研究

目的　探讨梗死相关血管重建后存活心肌的功能恢复与左室重塑进程和左室功能恢复的关系。方法　将心肌梗死区异常室壁运动节段中存活心肌的节段数做为量化存活心肌的指标。筛选 4 8例初次急性心肌梗死患者 ,心肌梗死后 (2 0± 12 )天成功的接受梗死相关血管的介入治疗术 ,术前 1～ 3天接受静息超声心动图和小剂量多巴酚丁胺负荷超声心动图检查 ,术后 (5 4± 1 6 )个月复查静息超声心动图。依小剂量多巴酚丁胺超声心动图负荷试验检测出的梗死相关的异常室壁节段中存活心肌的节段数 ,将 4 8例患者分为 :Ⅰ组 ,大量存活心肌 (存活心肌节段≥ 6段 ) 11例 ,Ⅱ组 ,少量存活心肌 (2段≤存活心肌节段≤ 5段 ) 2 9例 ,Ⅲ组 ,无存活心肌 (存活心肌节段 <2段 ) 8例。分别测定术前和术后静息状态下的左室舒张末容积、左室收缩末容积、左室射血分数和左室室壁节段运动积分指数。结果　重建血管术后 (5 4± 1 6 )个月随访发现梗死相关动脉血管重建后 ,梗死相关血管的异常室壁运动有不同程度的改善 ,Ⅰ组的左室收缩末容量由 (6 3± 8)ml降至 (4 7± 10 )ml(P <0 0 1) ;室壁运动积分指数由 1 4± 0 2降至 1 1± 0 1(P <0 0 1) ,左室射血分数由 (4 6± 9) %增至 (5 7± 10 ) % (P<0 0 1)。Ⅱ组的左室收缩末容量 (7     

急性心肌梗死后存活心肌对梗死相关血管晚期血运重建术后左室功能的影响

目的探讨存活心肌对急性心肌梗死(AMI)后梗死相关血管(IRA)晚期血运重建术后远期左室功能以及左室重构的影响.方法69例AMI未接受早期再灌注治疗者,于发病10～21 d行IRA经皮冠状动脉血运重建(PCI)术,术前于AMI发病后5～10 d应用小剂量多巴酚丁胺(5和10μg·min-1·kg-1)超声心动图负荷试验检测存活心肌,并分别测定和计算给药前后左室腔大小、左室射血分数(LVEF)以及室壁运动积分(WMS).按有无存活心肌分为存活心肌组和无存活心肌组,超声心动图随访术后6个月时两组左室腔大小、LVEF和WMS的变化.结果157个运动异常节段中89个节段(57%)有存活心肌,有存活心肌组26例(占38%),无存活心肌组43例(占62%).存活心肌组术后6个月LVEF较术前明显提高(P＜0.05),收缩末期容积指数(LVESVI)和WMS明显降低(P＜0.05和P＜0.01);而无存活心肌组LVEF较术前明显降低(P＜0.01),LVESVI和左室舒张末期容积指数(LVEDVI)较术前明显增加(P＜0.05),WMS无明显变化.存活心肌组多巴酚丁胺负荷时的LVEF和WMS明显改善,且与6个月时的测定值相近;而无存活心肌组PCI前应用多巴酚丁胺LVEF和WMS均无明显变化.结论AMI后有存活心肌者晚期血运重建有利于改善远期左室功能和减少左室重构.心肌梗死后早期小剂量多巴酚丁胺负荷状态下左室收缩功能的提高预示晚期血运重建术后心功能改善.     

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。     

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.     

小剂量多巴酚丁胺超声心动图对存活心肌及介入治疗的评价

目的　利用小剂量多巴酚丁胺超声心动图 (LDDE)显示心肌梗死部位存活心肌的存在及介入治疗术后整体心脏收缩功能的变化 ,评价介入治疗对存活心肌的作用。方法　选择前降支(LAD)单支闭塞病变拟行介入治疗患者 2 5例 ,均在术前做LDDE ,然后行经皮冠状动脉腔内成形术(PTCA)和支架术 ,术后 2～ 4个月复查二维超声心动图 (2DE) ,LDDE及二维超声心动图 (2DE)均采用16阶段半定量分析法 ,将LDDE显示≥ 2个相邻室壁运动不良节段 (RWMA)收缩功能改善者定为多巴酚丁胺阳性 ,并与介入治疗术后室壁运动改善相对比。术后RWMA改善定为存活心肌 ,并进行心肌收缩功能改善的评价。结果　多巴酚丁胺试验阳性 (持续改善和双向反应 )对存活心肌具有较高的预测价值 ,即在LDDE阳性的 118个室壁运动异常节段中有 10 3个节段介入治疗术后恢复 ,而LDDE阴性的 5 0个室壁运动异常节段仅有 11个节段恢复。此外 ,整体心功能的改善也与室壁运动异常的改善相一致 ,即术后射血分数 (EF)、心排血量 (CO)、心脏指数 (CI)等反映整体心脏功能的指标也有明显改善。结论　LDDE可以发现心肌梗塞部位存活心肌的存在 ,并可预测介入治疗后存活心肌的恢复和心脏整体收缩功能的改善     

应用心肌催活性评价冠心病介入治疗疗效

选择30例陈旧性心肌梗死患者,冠脉介入治疗术前和术后3～6个月分别行小剂量多巴酚丁胺负荷超声心动图试验,测定目标血管区心肌催活性及射血分数（EF）。发现以心肌催活性≥110％及EF增加≥15％为阳性衡量标准联合评价心肌缺血改善的准确性为86．7％。     

急性心肌梗塞后应用多巴酚丁胺负荷超声心动图对心肌存活性的研究

本文目的应用多巴酚丁胺负荷超声心动图研究急性心肌梗塞后梗塞区域心肌存活性。选择36例急性心肌梗塞患者，用5μg／kg·min多巴酚丁胺静脉滴注，体表超声心动图于用药前后对比观察梗塞区域心肌室壁运动和收缩期增厚率（T％），识别心肌存活性。36例患者分为576段心肌，基础状态下94段心肌运动消失，T％为0。静注5μg/kg·min多巴酚丁胺后，94段心肌中30段心肌恢复或部分恢复运动，T％增加121～60．0％。结果提示94段运动消失的心肌中30段（31．9％）具有存活性。表明多巴酚丁胺负荷超声心动图对急性心肌梗塞后存活心肌的识别是安全、可靠的，具有十分重要的临床意义。     

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。     

多巴酚丁胺负荷超声心动图试验在心肌梗死冠脉重？…

目的：采用多巴酚丁胺负荷超声心动图（ＤＳＥ）试验评价心肌梗死（ＭＩ）病人冠脉重建术（ＣＲＶ）后心室运动功能恢复的临床意义。方法：选择３０例急性心肌死病人,在冠脉重建术前,术后６个月,以不同剂量多巴酚丁胺（５,１０,１５,２０,２５,３０ｕｇ．ｋｇ＾－１．ｍｉｎ＾－１）连续静注５ｍｉｎ后,用二维超声心动图观察患者室壁运动异常（ＷＭＡ）节段的变化。结果：在不同剂量多巴酚丁胺下,ＣＲＶ前后患者的心率,收     

小剂量多巴酚丁胺负荷前后超声心动图和~(201)铊核素扫描对老年冠心病患者存活心肌的影响

目的评价预测急性心肌梗死(AMI)早期存活心肌的201铊核素扫描(~(201)TI)心肌显像和多巴酚丁胺超声心动图的作用。方法将49例患者,平均年龄(62±10)岁在心肌梗死10 d后进行冠状动脉造影,放射性核素造影,小剂量多巴酚丁胺超声心动图,放射性核素血管造影和静息~(201)TI心肌显像。19例患者进行了血运重建(血运重建组),30例患者给予药物治疗(药物治疗组)。一年后重复静息超声心动图和核素造影,分别评价节段性功能恢复和左室射血分数(LVEF)的变化。结果血运重建组患者,108个节段运动消失或反常运动,61个节段显示功能恢复。其敏感性在~(201)TI心肌显像预测节段性功能恢复为87%,多巴酚丁胺为66%(P0.001)而特异性和准确性分别有可比性。~(201)TI的活动度(峰值≥55%)是最佳的节段功能恢复的预测因素(P0.001)。血运重建后LVEF改善≥5%(P0.01)。在药物治疗组,149节段运动消失或反常运动有60节段显示功能恢复。随访8年,随访收缩储备节段大部分(94%)在多巴酚丁胺的有存活心肌在~(201)TI显像功能改善(86%)。在药物治疗组患者节段功能恢复较差或无收缩储备(38%)或无保留~(201)TI摄取(62%)。药物治疗组收缩反应是节段(P0.001)和整体(P0.01)左室功能改善的最好预测。结论多巴酚丁胺超声心动图可以预测心肌梗死后自行功能的恢复,而~(201)TI显像本身可识别患者心肌功能失调无收缩储备可受益于冠状动脉血运重建。     

Validation of viability assessment by electromechanical mapping by three-dimensional reconstruction with dobutamine stress echocardiography in patients with coronary artery disease

We evaluated the ability of electromechanical mapping (EMM) to discriminate between normal, viable, and nonviable (scarred) myocardium in patients with coronary artery disease versus dobutamine stress echocardiography (DSE) when the correspondence between the test and reference data sets is established via a common 3-dimensional reconstruction of the left ventricle. We studied 21 patients with coronary artery disease who underwent angiography, biplane ventriculography, and EMM within 1 month of DSE. A 3-dimensional left ventricular (LV) reconstruction was prepared from the ventriculogram and spatially aligned with EMM. EMM measurements of unipolar voltage, bipolar voltage, and local linear shortening were projected onto the three-dimensional left ventricle, averaged in each of 16 segments, and compared with DSE viability (normal, viable, scar) assessed at a core laboratory. All of the EMM measurements varied significantly (p <0.001) between the normal, viable, and scarred myocardium as assessed by DSE. Local linear shortening for normal, viable, and scarred segments was 10.4 +/- 6.5%, 7.8 +/- 5.6%, and 4.8 +/- 4.4%, respectively. In discriminating between these 3 groups, local linear shortening was more powerful than unipolar voltage or bipolar voltage (F = 20.765, F = 10.655, F = 4.795, respectively). Local linear shortening correlated best with viability, perhaps because it shares the same cognitive function as DSE. Three-dimensional analysis provides an anatomic framework that enables direct comparison of data from multiple imaging modalities rather than assuming segmental correspondence. Our results show that EMM provides significant on-line, diagnostic information on myocardial viability assessed by DSE on a segment-by-segment basis.     

Usefulness of dobutamine stress echocardiography in qualification of patients to angioplasty of infarct related artery

Late angioplasty of an infarct-related artery (IRA) performed weeks or months after myocardial infarction (MI) may restore blood flow in IRA and would result in improvement of regional wall motion. This study was designed to assess dobutamine stress echocardiography (DSE) in predicting the improvement of regional left ventricular (LV) function in patients after late PTCA of IRA. MATERIAL AND METHODS: 44 patients (36 M 8 F, mean age 54 +/- 7 year) who had a MI 15 +/- +/- 8 weeks earlier, were qualified to angioplasty of IRA when DSE showed the change in wall motion at the infarct zone--improved during low dose infusion (5-10 micrograms/kg/min) and/or worsened during a high dose dobutamine (up to 40 micrograms/kg/min). Regional wall motion was assessed by DSE performed at 2-7 days and 6-month after successful angioplasty. Wall motion score index (WMSI) decreased from 1.51 +/- 0.29 at rest to 1.31 +/- 0.28 at low-dose dobutamine infusion (p > 0.001) before angioplasty. Early after PTCA regional wall motion improves and baseline, exercise and rest values of WMSI decreased, compared with values before angioplasty. At baseline echocardiography 248 of segments were dyssynergic (112 hypokinetic, 125 akinetic and 10 dyskinetic). Viability during DSE was more frequent in segments with biphasic reaction during DSE than in segments showed monophasic reaction. In 34 patients control angiography (CA) was performed 6 month after successful PTCA. In this selected group CA showed significant restenosis of IRA in 12 pts (35% =, 9 of them showed positive DSE. Their base WMSI increased from 1.36 +/- 0.28 to 1.47 +/- 0.30 and peak stress WMSI from 1.32 +/- 0.29 to 1.60 +/- 0.30 (p < 0.001), respectively, between the exam just after PTCA comparing with the exam which detected restenosis. CONCLUSIONS: In some patients with infarction and a narrowed or occluded IRA the myocardium remains viable for a prolonged period. Improvement of wall motion during low-dose DSE and/or worsened during high dose DSE at infarct zone is a very useful tool in predicting of viable myocardium at infarct zone. DSE is an excellent method to demonstrate an immediate improvement in regional LV dysfunction after angioplasty of IRA. At 6 months' follow-up restenosis of IRA is often seen.     

Individual prediction of functional recovery after coronary revascularization in patients with ischemic cardiomyopathy: the scar-to-biphasic model

Currently, the prediction of improvement of left ventricular (LV) ejection fraction (EF) after revascularization in patients with ischemic cardiomyopathy relies only on viable myocardium extent, whereas both the amount of viable and scar tissue may be important. A model was developed, based on the amount of viable and nonviable myocardium, to predict functional recovery. Viable and scarred myocardium was defined by dobutamine stress echocardiography (DSE) in 108 consecutive patients. LVEF before and 9 to 12 months after revascularization was assessed by radionuclide ventriculography; an improvement of ≥5% was considered significant. In the 1,089 dysfunctional segments (63%), DSE elicited biphasic response in 216 segments (20%), sustained improvement in 205 (19%), worsening in 43 (4%), and no change in 625 (57%). LVEF improved in 39 patients (36%). Only the numbers of biphasic and scar segments were predictors of improvement or no improvement of LVEF (odds ratio 1.5, 95% confidence interval 1.2 to 1.7, p <0.0001 for biphasic segments; odds ratio 0.8, 95% confidence interval 0.7 to 0.9, p <0.0005 for scarred segments). The sustained improvement and worsening pattern were not predictive of improvement or no improvement. A regression function, based on the number of scar and biphasic segments, showed that the likelihood of recovery was 85% in patients with extensive biphasic tissue and no scars and 11% in patients with extensive scars and no biphasic myocardium. Patients with a mixture of scar and biphasic tissue had an intermediate likelihood of improvement (50%). In patients with ischemic cardiomyopathy and a mixture of viable and nonviable tissue, both numbers of viable and nonviable segments should be considered to accurately predict functional recovery after revascularization.     

Usefulness of the ejection fraction response to dobutamine infusion in predicting functional recovery after coronary artery bypass grafting in patients with left ventricular dysfunction

Quantification of dysfunctional but viable myocardium has high prognostic value for improvement of left ventricular (LV) function after coronary artery bypass grafting (CABG). Dobutamine stress echocardiography (DSE) can assess viable myocardium by segmental wall motion changes during stress. However, analysis of wall motion is subjective with only moderate interinstitutional agreement (70%) and frequently overestimates functional improvement after CABG. In contrast, calculation of ejection fraction (EF) is less subjective and allows a more precise quantification of global contractile reserve. The aim of the study was to compare the prognostic value of EF response and segmental wall motion changes during DSE for the prediction of LV functional recovery after CABG. Forty patients underwent DSE before CABG. EF responses were assessed at rest, low-dose dobutamine, and at peak stress using the biplane disk method. Wall motion was scored using a 16-segment 5-point model. Resting radionuclide ventriculography (RNV-LVEF), performed before and 8 ± 2 months after CABG, was used as an independent reference. Five patients were excluded because of perioperative infarction or poor echo images. In 11 of 35 patients, RNV-LVEF recovered >5%. Improvement in EF during dobutamine infusion predicted RNV-LVEF recovery after CABG significantly better than segmental wall motion changes (72% vs 53%, p = 0.03). A biphasic EF response (i.e., improvement in ≥10% at low dose and subsequent worsening at peak stress) had the highest predictive value (80%) for late functional recovery. In conclusion, EF response to dobutamine infusion was superior to segmental wall motion changes in predicting RNV-LVEF recovery after CABG.     

Comparison of functional recovery of mildly hypokinetic versus severely dysfunctional left ventricular segments after revascularization in patients with ischemic cardiomyopathy

Dysfunctional left ventricular (LV) segments showing contractile reserve during dobutamine stress echocardiography (DSE) are considered viable myocardium; functional recovery is expected after revascularization. Many segments, however, particularly mildly hypokinetic segments, do not recover. The reason for this failure is unknown. Two-dimensional echocardiography at rest and low-high-dose DSE were performed before revascularization in 114 consecutive patients with ischemic cardiomyopathy. Two-dimensional echocardiography at rest was repeated after 9 to 12 months. Segmental function was scored by a 5-point grading score. Functional recovery after revascularization was assessed in mildly hypokinetic (score 2, group I) and severely dysfunctional segments (score 3 to 5, group II). For each segment, functional recovery was defined as an improvement in functional score of > or =1 grade compared with the baseline score at rest. During low-dose DSE (up to 10 microg/kg/min), 183 group I segments (68%) and 438 group II (39%) segments had contractile reserve (p <0.0001). However, functional recovery was observed less frequently in group I segments (41%) than in group II segments (55%) with contractile reserve (p <0.005). During high-dose DSE (up to 40 microg/kg/min), in the group I segments with contractile reserve at the low dose, the sustained improvement pattern (indicating subendocardial scar) was prevalent (73%). After revascularization, 73% of segments with sustained improvement did not recover. Conversely, the biphasic response (indicating ischemically jeopardized myocardium) was observed only in 27% of group I segments. Functional recovery occurred in 39 of these segments (78%) (p <0.001 vs sustained improvement). Hence, mildly hypokinetic segments probably indicate the presence of subendocardial scars, and may explain the failure in functional recovery after revascularization.     

Usefulness of the ejection fraction response to dobutamine infusion in predicting functional recovery after coronary artery bypass grafting in patients with left ventricular dysfunction

Quantification of dysfunctional but viable myocardium has high prognostic value for improvement of left ventricular (LV) function after coronary artery bypass grafting (CABG). Dobutamine stress echocardiography (DSE) can assess viable myocardium by segmental wall motion changes during stress. However, analysis of wall motion is subjective with only moderate interinstitutional agreement (70%) and frequently overestimates functional improvement after CABG. In contrast, calculation of ejection fraction (EF) is less subjective and allows a more precise quantification of global contractile reserve. The aim of the study was to compare the prognostic value of EF response and segmental wall motion changes during DSE for the prediction of LV functional recovery after CABG. Forty patients underwent DSE before CABG. EF responses were assessed at rest, low-dose dobutamine, and at peak stress using the biplane disk method. Wall motion was scored using a 16-segment 5-point model. Resting radionuclide ventriculography (RNV-LVEF), performed before and 8 ± 2 months after CABG, was used as an independent reference. Five patients were excluded because of perioperative infarction or poor echo images. In 11 of 35 patients, RNV-LVEF recovered >5%. Improvement in EF during dobutamine infusion predicted RNV-LVEF recovery after CABG significantly better than segmental wall motion changes (72% vs 53%, p = 0.03). A biphasic EF response (i.e., improvement in ≥10% at low dose and subsequent worsening at peak stress) had the highest predictive value (80%) for late functional recovery. In conclusion, EF response to dobutamine infusion was superior to segmental wall motion changes in predicting RNV-LVEF recovery after CABG.     

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.     

CARTO电压标测识别猪急性心肌梗死模型中存活心肌的研究

目的 研究应用CARTO电压标测的方法识别猪急性心肌梗死模型中存活心肌的准确性和实用性.方法 用普通家猪13头,麻醉气管插管后行冠状动脉造影术,置入经皮腔内冠状动脉成形术球囊至冠状动脉左前降支远端,堵闭血流60～90 min,建立家猪心肌梗死模型.采用CARTO电压标测系统构建左心室,通过电压标测识别存活心肌.处死试验动物取出心脏,将心肌组织切成薄片后采用氯化三苯基四氮唑(TTC)染色法识别存活心肌.CARTO电压标测识别存活心肌的标准为0.5～1.5 mV为存活心肌,TTC染色存活心肌呈淡红色.将CARTO电压标测的结果与TTC染色结果进行对比.结果 所有猪均完成冠状动脉左前降支远端的封堵,2头分别在堵闭45和65 min时因心室颤动死亡.存活11头猪成功地建立急性心肌梗死模型.将猪的左心室分为16个节段,11头共176个节段,分别通过CARTO电压标测与TTC染色法对各节段心肌进行识别并评价两种方法的一致性,两者的一致性较好(Kappa=0.816,P＜0.001).以TTC染色检测出的存活心肌为标准,CARTO电压标测检测存活心肌的敏感度为71.8%,特异度为96.5%;准确度为90.9%.结论 运用经皮腔内冠状动脉成形术球囊封堵冠状动脉可成功建立猪急性心肌梗死模型.通过CARTO电压标测系统能够识别出模型中的存活心肌,为检测存活心肌提供了一个新的方法.     

Myocardial positive pre-ejection velocity accurately detects presence of viable myocardium, predicts recovery of left ventricular function and bears a prognostic value after surgical revascularization.

AIMS: To assess the accuracy of tissue Doppler imaging-derived myocardial positive pre-ejection velocity (+Vic) in detecting myocardial viability defined by dobutamine stress echocardiography (DSE), fluorine-18 fluorodeoxyglucose positron emission tomography (PET), and contrast-enhanced magnetic resonance imaging (MRI), and in predicting recovery of left ventricular (LV) function after coronary artery bypass grafting (CABG) in patients with chronic ischaemic LV dysfunction. METHODS AND RESULTS: +Vic in dysfunctional segments was recorded in 54 patients treated medically and 65 patients undergoing CABG [age 67 +/- 9 year; LV ejection fraction (EF) 30 +/- 6%]. A good agreement was observed between +Vic and detection of viable myocardium at DSE, PET, and MRI (kappa = 0.76). The presence of +Vic in greater than or equal to five dysfunctional segments had the highest sensitivity (93%) and specificity (60%) to identify patients (n = 28) with > or =10% increase in LV EF between baseline and 6-month echocardiogram. During follow-up (median 333 days, interquartile range 209-490 days), 13 cardiac events (6 deaths, 7 hospitalizations) occurred in 24 patients with small extent of viable myocardium (< 5 + Vic), whereas only four hospitalizations in 39 patients with > or =5 + Vic (54% vs. 10%; P < 0.001). CONCLUSION: The extent of +Vic in dysfunctional segments accurately predicts extent of viable myocardium and bears a clinical prognostic value in patients with ischaemic LV dysfunction considered for CABG.     

QT dispersion correlates to myocardial viability assessed by dobutamine stress echocardiography in patients with severely depressed left ventricular function due to coronary artery disease

BACKGROUND: QT dispersion is prolonged in numerous cardiac diseases, representing a general repolarization abnormality. AIM: To evaluate the influence of viable myocardium on QT dispersion in patients with severely depressed left ventricular (LV) function due to coronary artery disease. METHODS AND RESULTS: 103 patients with ischemic cardiomyopathy (LV ejection fraction [EF]: 25+/-6%) were studied. Patients underwent 12-lead electrocardiography to assess QT dispersion, and two-dimensional echocardiography to identify segmental dysfunction. Dobutamine stress echocardiography (DSE) was then performed to detect residual viability. Resting echo demonstrated 1260 dysfunctional segments; of these, 476 (38%) were viable. Substantial viability (> or =4 viable segments on DSE) was found in 62 (60%) patients. QT dispersion was lower in these patients, than in patients without viability (55+/-17 ms vs. 65+/-22 ms, P=0.012). Viable segments negatively correlated to QT dispersion (r=-0.333, P=0.001). In contrast, there was no correlation between LVEF and QT dispersion (r=-0.001, P=NS). CONCLUSIONS: There is a negative correlation between QT dispersion and the number of viable segments assessed by DSE. Patients with severely depressed LV function and a low QT dispersion probably have a substantial amount of viable tissue. Conversely, when QT dispersion is high, the likelihood of substantial viability is reduced.