Viable Myocardium Impact on Left Ventricular Function after Late Revascularization of Infarct-related Artery in Acute Myocardial Infarction

Objectives The long-term benefit of late reperfusion of infarct-related artery (IRA) after acute myocardial infarction (AMI) is controversial, and the benefit mechanisms remain uncertain. Low dose dobutamine stress echocardiography (LDSE) can identify viable myocardium and predict improvement of wall motion after revascularization. Methods Sixty-nine patients with first AMI who did not received early reperfusion therapy were studied by LDSE at 5 to 10 days after AMI. Wall motion abnormality and left ventricular size were measured at the same time. Successful PCI were done in all patients at 10 to 21 days after AMI onset. Patients were divided in two groups based on the presence or absence of viable myocardium. Echocardiography was repeated six months later. Results There were 157 motion abnormality segments. 89 segments (57%) were viable during LDSE. 26 patients (38%) with viability and 43 (62%) without. In viable group, left ventricular ejection fraction (LVEF) was increased (P < 0.05), and left ventricular end systolic volume index (LVESVI) and wall motion score (WMS) were decreased (P < 0.05 and P < 0.01) significantly at 6 months compared with baseline. But in patients without viability, LVEF was decreased (P < 0.01), and LVESVI and left ventricular end diastolic volume index (LVEDVI) were increased (P<0.05) significantly after 6 months, and the WMS did not changed (P > 0.05). LVEF increased (P< 0.05) and WMS decreased (P < 0.05) on LDSE during acute phase in patients with viability, but they were not changed in the nonviable group. Conclusions Late revascularization of IRA in patients with presence of viable myocardium after AMI is associated with long-term preservation left ventricular function and less ventricular remodeling. Improvement of left ventricular systolic function on LDSE indicates late phase recovery of left ventricular function after late revascularization.     

经皮冠状动脉介入治疗对急性心肌梗死患者左室重构的影响

经皮冠状动脉介入治疗能够有效防止左室重构 ,改善左室功能 ,但其作用机制和实行时机尚不明确。通过对其作用机制及实行时机的研究 ,为及时、有效实行PCI提供理论依据。     

Beneficial Effects of Delayed Opening the Infarct - related Artery on Late Phase Left Ventricular Function in Acute Anterior Myocardial Infarction

Objectives To assess the effect of delayed opening the infarct - related artery(IRA) by percutanous coronary intervention (PCI) on the late phase left ventricular function after acute anterior myocardial infarction. Methods 64 patients with initial Q -wave anterior myocardial infarction and the infarct- related arteries were total occluded conformed by angiogram at 2 to 14 days after onset were divided into successful PCI group and control group (not receiving PCI or the IRA not re - opened). 2 - DE was performed at early phase ( about 3 weeks) , 2 and 6months after onset of AMI respectively to detect the left ventricular function and left ventricular wall motion abnormality (VWMA). The total congestive heart failure events were recorded during 6 months follow-up. Results VWMA scores, left ventricular ejection fraction (LVEF), left ventricular end - diastolic and end-systolic volume indices (LVEDVI and LVDSVI)were similar in 2 groups at early phase and 2 months.There were no differences between early phase and 2months in each group too. VWMA scores and LVEF did not changed at 6 months in each group compared with the early phase and 2 months (P ＞ 0.05 ). But LVEDVI and LVESVI were significantly smaller in the successful PCI group than in the control group (P ＜0.01,P ＜ 0. 05 ). The congestive heart failure events were taken place in 19% of patients in control group compared with 2% in successful PCI group ( P ＞ 0.05 ).Conclusions Although the infarct size does not changed, delayed opening the IRA has beneficial effect to the late phase left ventricular dilatation after acute anterior myocardial infarction.     

Prevalence of Early Left Ventricular Thrombus after Primary Coronary Intervention for Acute Myocardial Infarction

The prevalence of left ventricular (LV) thrombus after acute myocardial infarction (AMI) has been reported high at 20–60%. Current reperfusion therapies such as thrombolysis have shown a trend toward reducing the incidence of LV thrombosis. However, the prevalence of LV thrombus after primary percutaneous coronary intervention (PCI) for AMI has not been systematically studied. At Massachusetts General Hospital 71 consecutive patients who underwent primary PCI for acute ST elevation MI were reviewed for the prevalence of LV thrombus evaluated by echocardiography. Echocardiography was performed within 5 days of infarction. PCI was successful in all patients. The time delay from symptom onset to intervention was 191 minutes. Thrombolysis in Myocardiol Infarction (TIMI) grade 3 flow was achieved in more than 80% of cases. Only 3 patients (4%) had echocardiographic evidence of LV thrombus. All 3 patients had anterior infarctions. The incidence among patients with anterior MI was 10% (3 of 30 patients). The prevalence of LV thrombus in patients treated with primary PCI for AMI is low (4%).     

急性ST段抬高性前壁心肌梗死患者的右心室功能分析

目的:评价急性前壁ST段抬高性心肌梗死直接经皮冠状动脉成形术(PCI)患者的右心室收缩和舒张功能变化。方法:分析46例急性前壁ST段抬高性心肌梗死患者[前降支近端完全闭塞者24例(前降支近端闭塞组),前降支远端急性闭塞者22例(前降支远端闭塞组)]直接PCI和35例冠状动脉造影"正常"患者(对照组)的临床、冠状动脉造影和心电图资料。采用二维心脏超声分别测定入选患者的右心室舒张末期容积(RVEDV),右心室收缩末期容积(RVESV),右心室射血分数(RVEF),平均肺动脉压(MPAP),左心室舒张末期容积(LVEDV),左心室收缩末期容积(LVESV),左心室射血分数(LVEF)和心脏指数(CI)。结果:与对照组相比,前降支远端闭塞组的平均肺动脉压无显著性差异(P>0.05),而右心室舒张末期容积和收缩末期容积增大,右心室射血分数降低;左心室舒张末期容积和收缩末期容积增加,左心室射血分数、心脏指数减低(P均<0.01)。与前降支远端闭塞组比较,前降支近端闭塞组的左心室舒张末期容积和收缩末期容积增加(P<0.01),心脏指数和左心室射血分数减少(P<0.01),右心室舒张末期容积收缩末期容积和平均肺动脉压增加(P<0.05～0.01),右心室射血分数降低(P<0.01)。多元线性回归分析表明前降支近端闭塞与右心室射血分数降低(R2=0.38,P<0.01)、右心室舒张末期容积增加(R2=0.410,P<0.01)有较好的相关性。2周后,前降支近端和远端闭塞组的右心室舒张末期容积、右心室收缩末期容积、平均肺动脉压和右心室射血分数无明显差异,而前降支近端闭塞患者的左心室舒张末期容积和收缩末期容积增大,左心室射血分数和心脏指数较低(P均<0.01)。结论:提示前降支近端闭塞可能伴右心室前壁部分心肌梗死导致右心室收缩和舒张功能障碍。     

糖尿病和非糖尿病急性前壁心肌梗死晚期成功血运重建术后左室功能的变化及其与存活心肌的关系

目的:比较糖尿病和非糖尿病前壁急性心肌梗死(AMI)晚期成功血运重建术对心肌梗死后远期左室功能和预后的影响以及与存活心肌的关系.方法:选择依据病史、心电图和心肌损伤标志物等检查证实为首次发作的前壁AMI,并于发病后2周左右接受冠状动脉介入治疗术(PCI)的患者共计125例,其中参照WHO诊断标准确诊为并发糖尿病者(A组)43例,未并发糖尿病者(B组)82例.PCI前行超声心动图检查,了解左室功能和梗死相关区域存活心肌的情况.详细分析和记录PCI前后冠状动脉造影的结果.并分别于PCI前和术后6 h、24 h采取静脉血检测血清CK-MB和肌钙蛋白T水平.术后6个月重复超声心动图检查,了解左室功能和室壁活动异常的变化,并随访其间主要心血管事件的发生情况.结果:冠状动脉造影显示,与B组相比,A组PCI后即刻靶血管TIMI 2级血流所占的比例较多,TIMI 3级较少(分别为P<0.05和P<0.01).术后CK-MB和肌钙蛋白T增高者A组明显多于B组(25.6%∶9.8%,P<0.05).小剂量多巴酚丁胺超声负荷试验结果示A组中62.8%和B组中56.1%的患者有存活心肌,2组相比差异无统计学意义(P>0.05).急性期2组左室射血分数(LVEF)、左室舒张末期容积指数(LVEDVI)、收缩末期容积指数(LVESVI)以及室壁运动积分(WMS)基本相同(均P>0.05).术后6个月随访,B组WMS明显减少,LVEF明显增高;而A组LVEF和WMS均无明显改善,LVEDVI反而增加;2组相比LVEDVI、LVESVI、LVEF和WMS均有明显差异(分别P<0.05和P<0.01).随访期间2组主要心血管事件的发生率差异无统计学意义(18.6%∶11.0%,P>0.05).结论:糖尿病AMI晚期成功血运重建对远期左室功能的改善作用较非糖尿病者差,其结果可能与糖尿病患者晚期PCI后缺血心肌未能得到有效再灌注或再灌注加重心肌损伤有关,而术前存活心肌可能不是影响其疗效的主要原因.     

心肌梗死择期经皮冠状动脉介入治疗对左心室重构和收缩功能的影响

目的:评价心肌梗死恢复期经皮冠状动脉介入治疗对左心室重构和收缩功能的影响。方法:将成功经皮冠状动脉介入治疗后又有造影复查的380例冠心病患者分为2组,①心肌梗死组224例,其中前壁梗死者106例,下壁梗死者102例,其它部位梗死者16例;介入治疗时梗死相关冠状动脉闭塞者118例,非闭塞者105例,梗死相关冠状动脉无法判断者1例。②非心肌梗死组156例。结果:380例中冠状动脉单支、双支和三支病变者占28％、37％和35％。①非心肌梗死组经皮冠状动脉介人治疗前、后左心室大小和收缩功能参数无显著变化,且在正常范围。②心肌梗死组经皮冠状动脉介入治疗前左心室舒张末容积(LVEDV)及指数(LVEDVI)、收缩末容积(LVESV)及指数(LVESVI)比非心肌梗死组均已显著增大(P均<0．001),左心室射血分数(LVEF)和左心室收缩末压(LVESP)均显著降低(P均<0．001);经皮冠状动脉介入治疗后LVESV、LVESVI均比治疗前显著降低(P均<0．001),每搏量(SV)及其指数(SVI)、LVEF、LVESP均显著提高(P<0．05-0．001);LVESVI降低和LVEF升高的程度比非心肌梗死组更显著(P<0．05～0．001);且在前壁和下壁心肌梗死患者间均无显著差异,疗效相当。③经皮冠状动脉介入治疗前梗死相关动脉闭塞和非闭塞患者,经皮冠状动脉介入治疗后LVEF均显著提高(P均<0．001),而LVESV、LVESVI仅在梗死相关动脉闭塞者显著降低(P均<0．05)。结论:急性心肌梗死患者恢复期已发生左心室重构伴收缩功能减低,择期经皮冠状动脉介入治疗可有效逆转左心室重构,提高左心室收缩功能。     

Repeated Low-dose of Erythropoietin is Associated with Improved Left Ventricular Function in Rat Acute Myocardial Infarction Model

Objective To evaluate the potential protective affects of Epo on left ventricular (LV) function and remodeling after acute myocardial infarction (MI). Methods Epo was injected into the peritoneum of male Wistar rats (250 g) during 6 weeks post induction of MI. Rats were divided into five groups: MI treated with single high dose (MT1, 5,000 U/kg, n = 10), single high dose (5,000 U/kg) and repeated high doses (MTHi, 1,000 U/kg twice a week; n = 8), or single high dose (5,000 U/kg) and repeated low doses (MTLo, 750 U/kg once a week, n = 10), MI non-treated (MNT, n = 10), sham (S, n = 5). Echocardiography was performed 3.6 ± 1.5 days and 43.7 ± 2.3 days post MI. Collagen deposition and infarct size were measured on histological sections using computerized image analysis. Apoptosis was assessed by ApopTag staining. Results Baseline fractional shortening (FS) was similar between groups. Six weeks after MI the FS of MTLo (26.9%) was significantly higher compared to MNT (17.8%), MT1 (19.5%) and MTH (22.3%) (p = 0.01). However, remodeling indices (end diastolic and end systolic areas, LV circumference) did not improve in the Epo groups, and even worsened in the MTHi group. There was significantly less collagen staining in non-infarct areas in MT1 and MTHi groups compared to MNT and MTLo (0.38 ± 0.3%, 0.49 ± 0.34%, vs 0.89 ± 0.41%, 0.95 ± 0.33%, respectively, p < 0.001). The number of ApopTag positive nucleus was significantly higher in the MNT group compared to the MT1, MTHi, MTLo groups (14.4 ± 8, 7.6 ± 4, 5.8 ± 7, 4.8 ± 5, respectively, p = 0.01 for trend). Conclusion Repeated low doses of Epo after MI improved LV function, but the role of Epo on remodeling is not clear. It did not reduce left ventricular indices, but reduces fibrosis and apoptosis. High Epo doses reduced LV function and aggravated remodeling.     

急性心肌梗死后早期T波倒置与左心室功能的关系

目的：探讨急性心肌梗死（ＡＭＩ）患者出现Ｔ波倒置的时间与左心室功能的关系。方法：监测４０例急性心肌梗死患者Ｔ波倒置的时间，并于发病后３～４周行核素心室造影测定左心室功能。结果：２４小时内出现Ｔ波倒置者左心室射血分数（ＬＶＥＦ）、高峰射血率、高峰充盈率均明显高于７２小时以上及２４～７２小时者。相关分析提示ＬＶＥＦ、高峰射血率、高峰充盈率均与Ｔ波倒置出现的时间呈负相关（ｒ分别＝－０．８２５，－０．７９３，－０．７３８；Ｐ均＜０．００１）。结论：急性心肌梗死后左心室功能与Ｔ波倒置时间关系密切。     

Gallopamil Activity on Asynergic Viable Myocardium in Acute Myocardial Infarction: Insights on Stunned and Hibernating Myocardium

The influence of the calcium antagonist gallopamil on the contractility of asynergic viable myocardium after acute myocardial infarction treated with thrombolysis was investigated by two-dimensional echocardiography. Sixteen patients with 1 viable segment(s), identified during the low-dose phase (up to 10 g/kg/min) of a dobutamine echocardiographic test (up to 40 g/kg/min) performed 4–5 days after a first acute myocardial infarction, were given a gallopamil intravenous bolus (50 g/kg) 12–24 hours later. Two-dimensional echocardiography was done before and 15 minutes after the bolus. A score index of 1 (normokinesis) to 4 (dyskinesis) and a 16-segment model were used. A segment was considered viable when a resting asynergy (score 2) improvement of 1 grade was seen during low-dose dobutamine. Follow-up echocardiograms were done 3–5 months later. A total of 30 viable segments were found; of these, 10 showed sustained improvement in contractility (group A) during high-dose dobutamine, while 20 exhibited a biphasic response returning to their basal contractile state (group B). After the gallopamil bolus, 9 of 10 group A segments improved their contractility, in comparison with 0 of 20 group B segments (P < .001). Infarct-related vessel significant (75%) coronary stenosis was present in the tributary vessel of 0 of 10 group A and of 20 of 20 group B segments (P < .001). At follow-up, 9 of 10 group A segments showed a spontaneous contractile improvement; of the 20 group B segments, 8 of 10 that underwent revascularization (7 angioplasty, 3 bypass graft) showed contractile improvement, in comparison with 0 of 10 segments not revascularized (P = .001). We conclude that gallopamil may reverse the contractile dysfunction of postischemic stunned myocardium in patients with acute myocardial infarction, whereas no effects are apparent on ischemic/hibernating myocardium.     

QT Dispersion and Viable Myocardium in Patients with Prior Myocardial Infarction and Severe Left Ventricular Dysfunction

Background: QT dispersion (QTd) has been found to correlate to the amount of viable myocardium in patients with Q‐wave myocardial infarction and well‐preserved LV function. However, this relationship is unknown in patients with severe left ventricular dysfunction. Methods: Thirty‐four patients with prior large myocardial infarction and severe left ventricular dysfunction underwent Tc‐99m sestamibi single photon emission cardiac tomography (SPECT) and F‐18 fluorodeoxyglucose (FDG) SPECT. Viability was defined as a defect relative count density (DCD) of at least 20% greater on FDG SPECT. QTd, corrected QT dispersion (QTcd), and QT coefficient of variation (cv) in patients with viable myocardium was compared to those without viable mvocardium in the infarct area. Results: Thirteen patients were excluded from analysis for poor FDG images or inadequate ECG tracings. Of the remaining patients, 10 (48%) were found to have viability on FDG SPECT. QTd, QTcd, and QTcv in patients with viability were: 58 ± 22 ms, 61 ± 23 ms, and 4.81 ± 1.76%, respectively, which did not differ significantly from those in patients without viability (QTd = 56 ± 14 ms, QTcd = 70 ± 16 ms and Qtcv = 5.06 ± 1.20% (P = NS]). Moreover, neither FDG defect size, nor LVEF correlated with QTd. Conclusions: This study indicates no relationship between QTd and viability in patients with myocardial infarction and severe left ventricular dysfunction. A.N.E. 2002;7(1):53–59     

清热化瘀方对热毒血瘀型急性ST段抬高型心肌梗死病人急诊PCI术后左室重构的影响

目的观察清热化瘀方对热毒血瘀型急性ST段抬高型心肌梗死(STEMI)病人急诊经皮冠状动脉介入(PCI)术后左室重构的影响。方法选取2018年5月1日—2019年12月1日在上海中医药大学附属曙光医院心血管科住院诊断为急性STEMI并行急诊PCI术的病人100例,随机分为中药组和对照组,各50例。对照组根据治疗指南给予标准化西医治疗,中药组在标准化西医治疗基础上加用清热化瘀方治疗,治疗时间为1个月。观察两组治疗前、治疗后7 d和治疗后30 d炎性因子、心功能指标变化;观察两组治疗前、治疗后1个月和随访6个月时左心室舒张末期内径(LVEDD)、左心室收缩末期内径(LVESD)、左心室后壁厚度(LVPWT)、室间隔厚度(IVSd)、左心室射血分数(LVEF)、左心室重量指数(LVMI)、左室舒张末期容积指数(LVEDVI)、左室收缩末期容积指数(LVESVI)水平变化。结果治疗后7 d,中药组白介素-8(IL-8)水平明显低于对照组,差异有统计学意义(P<0.05);治疗后30 d,中药组白介素-6(IL-6)水平明显低于对照组(P<0.05),而血管内皮生长因子(VEGF)水平...     

Effects of Perindopril on Left Ventricular Remodeling and Osteopontin Expression in Rats With Myocardial Infarction

Objectives To observe the effects of perindopril on left ventricular remodeling and myocardial osteopontin expression in rats with myocardial infarction. Methods In this study male adult SD rats were randomly divided into 3 groups: sham-operation group, MI-saline group and MI-perindopril group. Left anterior descending artery was ligated to generate myocardial infarction. Perindopril (2 mg/kg body weight/day) was administered from the next day of MI. Four weeks later, left ventricular diameter (LVEDD and LVESD) and left ventricular ejection fraction was estimated with echocardiography, LVSP, LVEDP and±dp/dtmax was detected with hemodynamic measurement, cardiomyocyte diameter and interstitial fibrosis infiltration were evaluated with histological methods, and myocardium osteopontin protein expression level was detected with western blot. Results ①Compared with the sham-operation group, all rats with MI developed significant systolic and diastolic dysfunction, as was indicated by decreased LVEF, LVSP and±dp/dtmax, as well as increased LVEDP. ②Rats with MI showed significantly dilated left ventricles and higher ventricular weight / body weight ratio, significantly increased cardiomyocyte diameter and marked interstitial fibrosis in the non-infarction area. ③Perindopril treatment partly prevented cardiac dysfunction and left ventricular remodeling as indicated by the parameters mentioned above. ④No osteopontin protein was detected in myocardium of sham-operation rats. In rats with MI, high level osteopontin protein expression was significantly inhibited by perindopril treatment. Conclusions In rats with MI, perindopril treatment significantly prevented left ventricular remodeling and myocardium osteopontin protein expression.     

急性心肌梗死对左心房的影响

急性心肌梗死后心脏收缩和舒张功能受损,直接影响到患者的预后.既往对心室收缩功能研究较多,对急性心肌梗死时左心房结构及功能变化的研究相对较少,而左心房结构及功能的变化又直接影响到心室的舒张功能及患者的预后.现就急性心肌梗死时左心房结构及功能的变化及其意义做一总结.     

急性心肌梗死合并左心室血栓的研究现状

左心室血栓形成是急性心肌梗死严重的并发症之一,尤其在急性前壁心肌梗死中的发生率更高,栓子脱落后主要可使体循环动脉栓塞,可引起脑、脾和肾等重要脏器功能障碍及肢体功能障碍而产生严重后果.因此,如何预防、早期诊断左心室血栓形成及防治不良后果,在临床医疗有重要意义.现对急性心肌梗死合并左心室血栓形成的研究状况做一综述.