Anterior ST-segment deviation during inferior myocardial infarction: arteriographic correlations during the acute phase

Electrocardiographic changes in the anterior wall lead in inferior myocardial infarction were studied in coronary angiographic findings in the acute stage. The subjects were 40 patients with initial inferior myocardial infarction due to right coronary lesions. ST segments were elevated in 7 patients, remained unchanged in 11 and were depressed in 22. Two patients predominantly perfused in the left coronary artery showed ST elevation. All seven patients who showed elevation of the ST segments had occlusion of the ventricular branch proximal to right. However, another 15 (68%) of the patients with occlusion of the same lesion did not show elevation of any ST segment. There was no difference in left ventricular ejection fraction between the groups. The regional ejection fraction at the left ventricular inferior wall was significantly (p less than 0.01) higher in the ST elevated group than in the ST depressed group. Elevation of the ST segments in the anterior wall lead was observed only when the right ventricular free wall sustained injury, and no elevation of any ST segment was observed when the range of injury in the inferoposterior wall was wide, even in the presence of injury to the right ventricular free wall.     

Reperfusion arrhythmias during coronary angioplasty for acute myocardial infarction predict ST-segment resolution

BACKGROUND: Despite early recanalization of an occluded infarct-related artery, myocardial reperfusion may remain impaired due to microvascular injury. Reperfusion arrhythmias may indicate successful microvascular reperfusion. METHODS: Microvascular reperfusion was assessed prospectively in 42 consecutive patients with ST-segment elevation acute myocardial infarction (AMI) by evaluation of the resolution of ST-segment elevation (<50% of initial level) immediately after successful coronary angioplasty. Patients were divided into two groups: those with ST resolution (n=24) and those without ST resolution (n=18). The presence of reperfusion arrhythmias immediately after recanalization was recorded. RESULTS: Patients with ST resolution were younger (54+/-12 years compared with 64+/-17 years, P=0.04), their pain-to-recanalization time was shorter (195+/-87 min compared with 294+/-179 min, P=0.05), they were less often diabetic (13% compared with 24%, P=0.05) and were more often given IIb/IIIa inhibitors (58% compared with 22%, P=0.02). Reperfusion arrhythmias were observed in 15 out of 24 patients with ST resolution (62%) but in only one out of 18 without ST resolution (5%) (P<0.01). Reperfusion arrhythmias included accelerated idioventricular rhythm, 13 (81%); multifocal ventricular premature beats, two (13%); and ventricular tachycardia, one (6%). The sensitivity and specificity of reperfusion arrhythmias for ST resolution were 62 and 95%, respectively. In a logistic regression model including age, time to treatment, diabetes, use of IIb/IIIa inhibitors and reperfusion arrhythmias, only the latter was found to be an independent predictor of ST resolution (P<0.01). CONCLUSION: Reperfusion arrhythmias following coronary angioplasty for AMI are a highly specific marker for ST resolution and may indicate successful microvascular reperfusion.     

ST-segment resolution 60 minutes after combination treatment of abciximab with reteplase or reteplase alone for acute myocardial infarction (30-day mortality results from the resolution of ST-segment after reperfusion therapy substudy)

The combination of abciximab with thrombolytic therapy when treating acute ST-elevation myocardial infarction has been hypothesized to enhance microvascular perfusion. Resolution of ST-segment elevation after thrombolytic therapy is believed to be a marker of myocardial reperfusion and to predict mortality rate. Among 16,588 patients enrolled in the Fifth Global Use of Strategies to Open Occluded Arteries in Acute Myocardial Infarction trial, 1,764 consecutive patients from selected centers had their study electrocardiograms evaluated by a core laboratory for ST-segment deviation resolution 60 minutes after treatment. Patients were categorized into 4 groups: complete resolution (>70%), partial resolution (<70% to 30%), no resolution (<30%), and worsening ST-segment deviation. Patients treated with reteplase or a combination of reteplase plus abciximab had similar rates of complete resolution (32% vs 34%), partial resolution (29% vs 27%), no resolution (15% vs 16%), and worsening ST-segment elevation (23 vs 23%; p = 0.59). The 30-day mortality rates in these 4 groups were 2.1%, 5.2%, 5.5%, and 8.1% (p <0.001). Even after accounting for baseline variables, incomplete ST-segment resolution (<70%) was associated with an increased risk of death within 30 days (adjusted hazard ratio 2.41, 95% confidence interval 1.25 to 4.63, p <0.008). Thus, ST-segment resolution at 60 minutes was no different in patients treated with full-dose reteplase from those treated with a combination of abciximab and reteplase. Patients with >70% ST-segment resolution within 60 minutes had markedly decreased mortality rates, irrespective of treatment.     

急性心肌梗死患者经皮冠状动脉介入治疗术后ST段回落不良的分析

目的探讨ST段抬高急性心肌梗死(AMI)患者直接PCI术后ST段回落不良的相关因素。方法173例符合ST段抬高AMI诊断并行直接PCI的患者,计算其心电图ST段回落指数,运用logistic回归分析影响ST段回落的相关因素。结果冠状动脉造影心肌呈色分级0/1(OR=2.936)、病变部位(OR=2.121)、胸痛开始到再灌注的时间(OR=1.314)、梗死前心绞痛(OR=1.053)是影响术后心电图ST段恢复的相关因素。结论AMI直接PCI术后心电图ST段恢复程度与上述因素有关。     

Effect of preinfarction angina pectoris on ST-segment resolution after primary coronary angioplasty for acute myocardial infarction

The presence of preinfarction angina has been shown to exert a favorable effect on left ventricular function after acute myocardial infarction (AMI). Whether or not preinfarction angina is beneficial for myocardial tissue reperfusion, however, remains to be determined. We sought to evaluate the influence of preinfarction angina on resolution of ST-segment elevation, which could be affected by microcirculatory damage after recanalization therapy. We studied 96 patients with a first AMI in whom Thrombolysis In Myocardial Infarction (TIMI)-3 flow in the infarct-related artery was established by primary angioplasty. Percent reduction in the sum of ST elevation from baseline to 1 hour after angioplasty (percent delta summation operator ST) was examined. Poor ST resolution, defined as percent delta summation operator ST <50%, was observed in 25 patients, who had a worse clinical outcome, larger infarct size, and poorer left ventricular function. On multivariate analysis, the absence of preinfarction angina, as well as anterior wall infarction, were major independent predictors of poor ST resolution, whereas age, sex, coronary risk factors, ischemic time, Killip class on admission, multivessel disease, initial TIMI flow grade, and extent of collaterals were not significant. Patients with preinfarction angina had a greater degree of ST-segment resolution than those without angina (71 +/- 21% vs 49 +/- 43%, p = 0.02). Additional ST elevation after reperfusion was noted exclusively in patients without preinfarction angina (p = 0.02). Preinfarction angina is associated with a greater degree of ST-segment resolution in patients with TIMI-3 flow after primary angioplasty, suggesting a protective effect of preinfarction angina against microcirculatory damage after reperfusion.     

急性心肌梗死直接PTCA后早期ST段改变及其临床意义

目的探讨急性心肌梗死（AM I）行直接经皮冠状动脉腔内成形术（PTCA）+支架术后心电图早期ST段回落幅度与左心室结构、功能的关系。方法首次患AM I并接受直接PTCA的患者32例。比较PTCA术前和术后1 hST段抬高的高度,按ST段下移>50%及ST段下移<50%,分别分为A组（21例）和B组（11例）。所有患者于术后4周进行临床评估和二维彩色多普勒超声心动图检查。结果随访期间两组患者均未发生死亡,A组心功能ⅢⅣ级2例,B组心功能ⅢⅣ级5例（P<0.05）。4周后A组左心室射血分数（LVEF）、收缩末容积指数（LVESVI）、舒张末容积指数（LVEDVI）和全心室壁运动指数（GWMSI）均显著优于B组（P<0.05）;梗死区室壁运动指数（RWMSI）在两组间无显著性差异。结论成功的直接PTCA后ST段的早期回落是反映心肌组织再灌注的简便可靠的指标,ST段回落>50%者的心脏功能、室壁运动及左心室重构情况明显优于ST段回落<50%者。     

急性心肌梗塞患者再灌注治疗后ST段回落的影响因素

目的:分析急性心肌梗塞(AMI)患者再灌注治疗后ST段回落(STR)的影响因素。方法:收集114例溶栓和71例急诊经皮冠状动脉介入(PCI)治疗的AMI患者,按溶栓或PCI治疗后90min心电图单导联STR分别分为STR<50%和STR≥50%组,对临床资料中多个变量进行单因素分析和Logistic回归分析。结果:单因素分析显示,与STR<50%患者相比,PCI组STR≥50%患者入院时血糖(Glu)(P=0.016)和白细胞(WBC)(P=0.011)较低,单支冠脉血管病变者较多(P=0.023),溶栓组STR≥50%患者Glu(P=0.002)、WBC(P=0.036)和killip心功能分级(P=0.012)较低,发病到治疗的时间更短(P=0.016),有高血压病史者(P=0.033)和前壁梗塞者(P=0.011)较少。Logistic回归分析结果PCI组最终进入方程的变量为入院时Glu(B=-0.299,P=0.021)和WBC(B=-0.201,P=0.026),溶栓组进入方程的变量有高血压病史(B=-0.978,P=0.027)、GIu(B=-0.252,P=0.003)和治疗前时间(B=-0.004,P=0.018)。结论:入院时血糖水平为AMI患者PCI或溶栓治疗后ST段回落独立的影响因素,WBC是PCI患者ST段回落的另一影响因素,高血压病史和治疗前时间则是溶栓治疗患者ST段回落的另外两个影响因素。     

Enoxaparin for the treatment of acute myocardial infarction with persistent ST-segment elevation

Enoxaparin (E) is a low-molecular-weight heparin which has been proven more effective than unfractionated heparin (UFH) for the treatment of non-ST-segment elevation acute coronary syndromes. Limited and inconclusive on the other hand, are the data on the use of E in acute myocardial infarction with persistent ST-segment elevation (STEAMI). Therefore, we performed a review of the literature in order to evaluate the level of evidence relative to the efficacy and safety of E in such a clinical setting. The effect of E in STEAMI has been evaluated in 7 clinical studies, including a total of about 9500 patients. Compared to placebo, E resulted more effective on the incidence of the combined end-point of death, re-infarction and recurrent angina in the study by Glick et al. and on the patency of the infarct-related artery in the AMI-SK study. Compared to UFH, E resulted more effective on the incidence of the combined end-point of death, reinfarction and unstable angina in the study by Baird et al. and of in-hospital re-infarction and refractory ischemia rates in both ASSENT-3 and ASSENT-3 PLUS, while the effect on the patency of the infarct-related artery, which was evaluated in HART-II and ENTIRE-TIMI 23, resulted non univocal. Overall, bleeding complications were more frequent than with placebo and comparable to UFH, with the exception of ASSENT-3 PLUS where pre-hospital administration of E was associated with a doubled incidence of intracranial bleeding (although only in patients older than 75 years). In conclusion, the administration of E, in association with aspirin and thrombolytics, already appears a possible therapeutic option for the treatment of STEAMI, due to its good efficacy and safety profile, along with its easiness of use. However, prior to have its use recommended, the current B level of evidence of a superior efficacy and safety compared to UFH needs to be reinforced. Further-more, some open issues relative to the use of E in particular settings (aged patients, in association with glycoprotein IIb/IIIa inhibitors and during percutaneous coronary revascularization) need to be clarified.     

ST-segment elevation during dobutamine stress testing predicts functional recovery after acute myocardial infarction

OBJECTIVES: The aims of this study were (1) to assess the relation between ST-segment elevation and wall motion response occurring during dobutamine testing and (2) to evaluate the usefulness of stress-induced ST-segment elevation for predicting functional recovery after acute myocardial infarction. BACKGROUND: Clinical significance of stress-induced ST-segment elevation after acute myocardial infarction remains controversial. According to previous studies, it may reflect a larger infarcted area, depressed left ventricular function, left ventricular aneurysm, stress-induced dyskinesia, residual myocardial ischemia, or viability in the affected region. Whether transient ST-segment elevation occurring during dobutamine testing may predict functional recovery is unknown. METHODS AND RESULTS: We studied 38 patients who underwent dobutamine stress testing early (5 +/- 2 days) after a first acute myocardial infarction. Dobutamine was infused at increasing doses from 5 to a maximum of 40 microg/kg per minute, with the addition of up to 1 mg of atropine if the target rate could not be reached by dobutamine alone. Twelve-lead electrocardiography and cross-sectional echocardiography were continuously monitored throughout the test. Dobutamine-induced ST-segment elevation was defined as a new or worsening >/=1 mm elevation, 80 ms after J point, in >/=2 infarct-related leads. Quantitative angiography was available in all patients before hospital discharge. Follow-up resting echocardiography was recorded in all patients 12 to 18 months after the acute event. ST-segment elevation was observed in 20 of the 38 patients. There were no significant differences between patients with and those without dobutamine-induced ST-segment elevation in age, site of infarction, peak level of total creatine kinase enzyme, and use of thrombolytic therapy, angioplasty, or both. Persistent akinesis without change during dobutamine stress testing was more frequently observed in patients without ST elevation (P <. 05). A biphasic response during dobutamine testing was more frequently observed in patients with ST-segment elevation (P =.01). Multivariate analysis selected 2 independent variables associated with ST-segment elevation: a biphasic response during dobutamine stress (chi-square = 7.3; P =.007) and the minimal lumen diameter of the infarct-related vessel at quantitative angiography (chi-square = 5.5; P <.02). Functional recovery was demonstrated in 26 patients. Sensitivity of ST-segment elevation for the prediction of functional recovery was 69%, specificity 83%, positive predictive value 90%, and accuracy 74%. Two independent variables predicting functional recovery were selected: dobutamine-induced ST-segment elevation (chi-square = 9.1; P =.003) and a biphasic response during stress (chi-square = 6.15; P =.013). CONCLUSIONS: Dobutamine-induced ST-segment elevation in the infarct-related leads is an ancillary sign of viable myocardium in jeopardy. It has a high specificity and an acceptable sensitivity for the prediction of functional recovery after acute myocardial infarction.     

Reliability of resolution of ST-segment elevation after coronary reperfusion in predicting myocardial salvage in anterior wall acute myocardial infarction

Resolution of ST-segment elevation (ST resolution) after reperfusion therapy has been shown to correlate with improved left ventricular (LV) function in patients with acute myocardial infarction (AMI). However, not all patients with ST resolution have preserved LV function. We evaluated the clinical significance of ST resolution in 129 patients with anterior wall AMI who underwent successful coronary recanalization within 6 hours after symptom onset by studying the relation to myocardial blush grade, another angiographic marker of myocardial reperfusion. A reduction of > or =50% in ST-segment elevation after recanalization was defined as ST resolution. Ninety-eight patients had ST resolution and 31 patients did not. Patients with ST resolution were subdivided into 2 groups according to myocardial blush grade after recanalization: 67 patients with blush grade 2 or 3, and 31 with blush grade 0 or 1. The QRS score after recanalization was higher (5.9 +/- 1.9 vs 3.4 +/- 2.0, p <0.01) and predischarge LV ejection fraction was lower (39 +/- 8% vs 57 +/- 9%, p <0.01) in patients with blush grade 0 or 1 than in those with blush grade 2 or 3. However, the QRS score after recanalization and the predischarge LV ejection fraction were similar in patients who had ST resolution with blush grade 0 or 1 and in those without ST resolution. Our findings suggest that ST resolution after recanalization does not consistently predict myocardial salvage in patients with anterior AMI.     

ST-segment elevation on Q-leads during exercise in patients with ST-segment elevation at rest after myocardial infarction

INTRODUCTION: ST-segment elevation on Q-leads after an acute myocardial infarction is related to a greater infarct size. The meaning of a further exercise-induced ST-segment elevation in these patients has not been analyzed. METHOD: Thirty-six patients with ST-segment elevation on Q-leads were studied after a first acute myocardial infarction. Exercise testing and cardiac catheterization were performed at the first week. Left ventricular volumes (ml/m(2)); the extent of abnormal wall motion (AWM: chords); contractile reserve (AWM improvement with low dose dobutamine) and coronary patency in the culprit artery were analyzed. Cardiac catheterization was repeated at the sixth month in 20 patients; systolic recovery (AWM improvement), left ventricular volumes and coronary patency were again evaluated. RESULTS: Patients with exercise-induced ST-segment elevation in two or more Q-leads (n=21) showed lesser contractile reserve (6+/-6 vs. 12+/-7 chords, P=0.01) than patients without exercise-induced ST-segment elevation (n=13). AWM (F=8.1) and absence of exercise-induced ST-segment elevation (F=9.5; positive predictive value: 80%; negative predictive value: 68%) were the only independent predictors of contractile reserve. Nevertheless, this electrocardiographic sign was not related to left ventricular volumes, coronary patency or systolic function and it did not predicted late systolic recovery. CONCLUSIONS: In patients with baseline ST-segment elevation on Q-leads an exercise-induced ST-segment elevation is independently related to a lesser contractile reserve but not to the evolution of volumes or regional dysfunction during the first 6 months post-infarction. Therefore, the clinical value of this sign seems to be limited to the non-invasive detection of myocardial viability during the early post-infarction phase.     

急性ST段抬高性心肌梗死患者直接经皮冠状动脉介入治疗再灌注时间对ST段回落的影响

目的探讨直接经皮冠状动脉介入(percutaneous coronary intervention,PCI)治疗中症状发作-球囊扩张时间(symptom-onset-to-balloon,SOTB)对再灌注后心电图ST段的回落、住院期间左心室射血分数、6个月内总的主要心血管事件(包括心绞痛、再发心肌梗死、因心血管事件再入院、心力衰竭和死亡等)发生率的影响。方法回顾性分析2005年1月至2006年7月于北京大学深圳医院行直接PCI治疗的ST段抬高性心肌梗死(ST-elevation myocardial infarction,STEMI)患者225例的基线资料、心电图资料以及随访资料,比较不同时间SOTB(>3 h及≤3 h)术前、术后1 h ST段抬高总和恢复百分比(sumSTR)%、住院期间超声心动图所测的左心室射血分数、随访6个月的主要心血管事件发生率。结果SOTB≤3 h组PCI治疗后1 h ST段完全回落≥70%的患者比例明显高于SOTB>3 h组,差异有统计学意义(57.4%vs.43.2%,P=0.005);住院期间左心室射血分数高于SOTB>3 h组,差异有统计学意义(57.69%±7.64%vs.53.80%±9.03%,P=0.014);6个月主要心血管事件发生率低与SOTB>3 h组,差异有统计学意义(14.9%vs.35.4%,P=0.001)。结论 STEMI患者PCI治疗中SOTB短,ST段回落就迅速而完全,住院期间的左心室射血分数高,6个月主要心血管事件发生率低。