ST-segment elevation myocardial infarction

Opinion statement ST-segment elevation myocardial infarction (MI) is an emergency medical condition. Expediting the steps leading to coronary reperfusion is of critical importance in improving survival after acute MI. After the diagnosis of acute MI is made, patients should be treated with oxygen, aspirin, nitroglycerin, beta-blockers, heparin, and analgesics, barring any contraindications. If an experienced cardiac catheterization laboratory is available within 60 to 90 minutes, then catheter-based reperfusion therapy is recommended; otherwise, thrombolysis should be considered as an alternate therapy. Therapy with a reduced-dose thrombolytic agent and a glycoprotein IIb/IIIa receptor inhibitor appears to be of an added benefit in establishing TIMI (Thrombolysis in Myocardial Infarction) 3 flow, but this approach awaits final approval prior to widespread use. The adjunctive use of glycoprotein IIb/IIIa receptor inhibitors with percutaneous transluminal coronary angioplasty, with or without stenting, appears to be beneficial and is being used more frequently in the acute setting. Coronary angiography should be performed in patients who fail to respond to thrombolytic therapy or who have evidence of recurrent ischemia. This procedure should not be routinely performed in patients who have responded to thrombolytic therapy. Four to 6 days after an acute MI event, assessment of left ventricular function is recommended. Submaximal exercise test (with or without nuclear or echocardiographic imaging) should be considered in patients prior to discharge from the hospital—an exception can be made in patients with one-vessel disease treated successfully with percutaneous transluminal coronary angioplasty. After discharge, a regular exercise test should be obtained 4 to 6 weeks after an uncomplicated acute MI event. Secondary prevention measures such as weight loss, cessation of smoking, aspirin, beta-blockers, lipid-lowering agents, and angiotensin-converting enzyme inhibitors should be considered in all patients, barring contraindications.     

Electrocardiographic scores of severity and acuteness of myocardial ischemia predict myocardial salvage in patients with anterior ST-segment elevation myocardial infarction

Background

Terminal “QRS distortion” on the electrocardiogram (ECG) (based on Sclarovsky-Birnbaum's Grades of Ischemia Score) is a sign of severe ischemia, associated with adverse cardiovascular outcome in ST-segment elevation myocardial infarction (STEMI). In addition, ECG indices of the acuteness of ischemia (based on Anderson-Wilkins Acuteness Score) indicate myocardial salvage potential. We assessed whether severe ischemia with or without acute ischemia is predictive of infarct size (IS), myocardial salvage index (MSI) and left ventricular ejection fraction (LVEF) in anterior versus inferior infarct locations.

急性前壁心肌梗死伴不同下壁导联ST段改变的临床特点

目的探讨ST段抬高急性前壁心肌梗死(简称心梗)伴不同下壁导联ST段改变患者的梗死相关血管以及梗死面积及心功能情况。方法73例急性前壁心梗患者,根据入院时心电图下壁导联ST段改变情况将患者分为3组:A组为Ⅱ、Ⅲ、aVF中至少两个导联ST段抬高;B组为Ⅱ、Ⅲ、aVF中至少两个导联ST段压低,C组为Ⅱ、Ⅲ、aVF中少于两个导联ST段有改变。比较三组CK最大值,左室射血分数以及梗死相关血管(IRCA)。结果CK最大值3组比较A组最低(1280±531IU/Lvs2034±911,1677±630IU/L,P<0.01);左室射血分数A组最高(0.54±0.09vs0.48±0.07,0.47±0.08,P<0.01);三组IRCAA组中85.7%的患者位于“绕过心尖的左前降支(LAD)”的中远段,有14.3%的患者位于右冠状动脉(RCA)的近段;B组的患者中全部为非“绕过心尖的LAD”,其中有70.4%的患者位于非“绕过心尖的LAD”的近段;C组中有96.7%的患者为非“绕过心尖的LAD”,其中有73.3%的患者位于非“绕过心尖的LAD”的近中段,三组比较差异有显著性(P<0.01)。结论IRCA为LAD的急性前壁心梗时下壁ST段改变可能与LAD长度和病变部位有关;前壁合并下壁ST段同时抬高的患者若IRCA为“绕过心尖的LAD”,其梗死面积较小,心功能较好。     

Early management of ST-segment elevation myocardial infarction

Improvements in the management of ST-segment elevation myocardial infarction(STEMI) have led to a reduction in the acute and long-term mortality rates. The first important decision in the care of patients who have STEMI is the method of reperfusion.Whether percutaneous intervention (PCI) or fibrinolytic therapy is chosen depends on a number of factors. This article reviews the data on PCI and fibrinolytics in the context of consensus guidelines, outlines adjunctive medical therapies important in the first 24 hours, and discusses a strategy for making the decisions and a hypothetical construct for evaluating new drugs and procedures in the future.     

Contemporary management of ST-segment elevation myocardial infarction

ST-elevation myocardial infarction (STEMI), which constitutes nearly 25–40 % of current acute myocardial infarction (AMI) cases, is a medical emergency that requires prompt recognition and treatment. Since the 2013 STEMI practice guidelines, a wealth of additional data that may further advance optimal STEMI practices has emerged. These data highlight the importance of improving patient treatment and transport algorithms for STEMI from non-primary percutaneous coronary intervention (PCI) centers. In addition, a focus on the reduction of total pain-to-balloon (P2B) times rather than simply door-to-balloon (D2B) times may further improve outcomes after primary PCI for STEMI. The early administration of newer oral P2Y12 inhibitors, including crushed forms of these agents for faster absorption, represents another treatment advancement. Recent data also suggest avoiding concurrent morphine use due to interactions with P2Y12 inhibitors. Furthermore, new technological advancements and investigational therapies, including Bioresorbable Vascular Scaffolds and the use of pre-intervention intravenous microbubbles with transthoracic ultrasound, hold promise to play a useful role in future STEMI care. Despite these advancements, the prompt recognition of STEMI, at both the patient and health care system level, remains the cornerstone of optimal treatment.     

Determinants of ST-segment level in lead aVR in anterior wall acute myocardial infarction with ST-segment elevation

Background

This study aimed to clarify the determinants of ST-segment level in lead aVR in anterior wall acute myocardial infarction (AAMI).

Methods

We analyzed ST-segment levels in all 12 leads on admission and emergency coronary angiographic findings in 261 patients with a first AAMI with ST-segment elevation. The length of the left anterior descending coronary artery (LAD) was classified as follows: short = not reaching the apex; medium = perfusing less than 25% of the inferior wall; long = perfusing 25% or more of the inferior wall.

Results

The ST-segment level in lead aVR correlated significantly with the ST-segment levels in leads I, II, III, aVF, V₁, and V_3-6, especially with those in leads II and V₆ (r = −0.63, P < .001; r = −0.61, P < .001; respectively). Patients with a proximal LAD occlusion had a greater ST-segment level in lead aVR than those with a distal LAD occlusion (P < .001). Patients with a long LAD had a lower ST-segment level than those with a short or medium LAD (P < .05).

Conclusions

The ST-segment levels, especially in leads II and V₆, the site of the LAD occlusion, and the length of the LAD affect the ST-segment level in lead aVR in ST-segment elevation AAMI.     

Pneumomediastinum mimicking acute ST-segment elevation myocardial infarction

Pneumomediastinum is characterized by dissecting air within the connective tissues supporting the mediastinum. This condition has been associated with multiple electrocardiographic abnormalities including T-wave inversion, electrical alternans, loss of R wave progression, and low voltage QRS. We describe a case of pneumomediastinum with electrocardiographic changes mimicking acute ST-segment elevation myocardial infarction. Laboratory studies and echocardiography demonstrated no evidence of myocardial injury, and the electrocardiographic abnormality promptly resolved with resolution of the pneumomediastinum. The apparent ST-segment elevation appeared to be the result of electrocardiographic artifact, possibly related to epidermal stretch synchronous with the cardiac cycles.     

Prehospital ticagrelor in ST-segment elevation myocardial infarction

The direct-acting platelet P2Y12 receptor antagonist ticagrelor can reduce the incidence of major adverse cardiovascular events when administered at hospital admission to patients with ST-segment elevation myocardial infarction(STEMI). Whether prehospital administration of ticagrelor can improve coronary reperfusion and the clinical outcome is unknown. Methods We conducted an international, multicenter, randomized, doubleblind study involving 1862 patients with ongoing STEMI of less than 6 hours' duration, comparing prehospital(in the ambulance) versus in-hospital(in the catheterization laboratory) treatment with ticagrelor. The coprimary end points were the proportion of patients who did not have a 70% or greater resolution of ST-segment elevation before percutaneous coronary intervention(PCI) and the proportion of patients who did not have Thrombolysis in Myocardial Infarction flow grade 3 in the infarct-related artery at initial angiography.Secondary end points included the rates of major adverse cardiovascular events and definite stent thrombosis at30 days. Results The median time from randomization to angiography was 48 minutes, and the median time difference between the two treatment strategies was 31 minutes. The two coprimary end points did not differsignificantly between the prehospital and in-hospital groups. The absence of ST-segment elevation resolution of 70% or greater after PCI(a secondary end point) was reported for 42.5% and 47.5% of the patients, respectively. The rates of major adverse cardiovascular events did not differ significantly between the two study groups. The rates of definite stent thrombosis were lower in the prehospital group than in the in-hospital group(0% vs. 0.8% in the first 24 hours; 0.2% vs. 1.2% at 30 days). Rates of major bleeding events were low and virtually identical in the two groups, regardless of the bleeding definition used. Conclusions Prehospital administration of ticagrelor in patients with acute STEMI appeared to be safe but did not improve pre-PCI coronary reperfusion.     

Bleeding risk in ST-segment elevation myocardial infarction

Coronary reperfusion of acute coronary syndromes with ST segment elevation requires medical treatment involving potential thrombolysis as well as very potent anticoagulant and antiplatelet medications. In such a therapeutic setting, the risk of bleeding complications may be high and should be taken into account accordingly. An accurate definition of these bleeding complications is crucial in order to compare all currently available treatments and strategies appropriately. The heterogeneous definitions often published in the literature make any valid interpretations of the results very difficult. These bleeding complications, which affect negatively the outcome of patients undergoing treatment should be adequately anticipated in our treatment strategies. An exhaustive knowledge of the bleeding risk factors is necessary in order to adjust the treatment modalities. The occurrence of bleeding may be related to the vascular approach used for cardiac catheterization. In this respect, the superiority of the radial approach has been widely demonstrated. In addition, certain instances of bleeding are not related to the vascular approach, such as digestive and neurological bleeding which can have very severe consequences. Consequently, it is necessary to adapt treatments with heterogeneous potential for bleeding to individual bleeding risk factors, which may be quantified by scores measuring the bleeding risk. Finally, treatment combinations must often be carefully tailored to the characteristics of each individual patient.     

Reperfusion paradox in ST-segment elevation myocardial infarction

A transformation in ST-segment elevation myocardial infarction (STEMI) care in the United States has unfolded. It asserts superior reperfusion with primary percutaneous coronary intervention (PPCI) over fibrinolysis on the basis of studies showing the former method to be superior for reperfusion of patients with STEMI. Although clear benefit has resulted from national programs directed toward achieving shorter times to PPCI in facilities with around-the-clock access, most patients present to non-PPCI hospitals. Because delay to PPCI for most patients with STEMI presenting to non-PPCI centers remains outside current guidelines, many are denied benefit from pharmacologic therapy. This article describes why this approach creates a treatment paradox in which more effort to improve treatment for patients with PPCI for acute STEMI often leads to unnecessary avoidance and delay in the use of fibrinolysis. Recent evidence confirms the unfavorable consequences of delay to PPCI and that early prehospital fibrinolysis combined with strategic mechanical co-interventions affords excellent outcomes. The authors believe it is time to embrace an integrated dual reperfusion strategy to best serve all patients with STEMI.     

Clinical trials with ST-segment elevation myocardial infarction

It is with great interest that we read the article ‘Outcomesof patients in clinical trials with ST-segment elevation myocardialinfarction among countries with different gross national incomes’by Orlandini et al     

Hypercalcemia-induced ST-segment elevation mimicking acute myocardial infarction

We describe a patient who presented with abdominal pain radiating to the chest and ST elevation in the precordial leads, mimicking acute myocardial infarction. Urgent coronary angiography revealed normal coronary arteries and his serum troponin has not increased. Subsequently, he was found to have severe hypercalcemia. ST segment elevation resolved after correction of hypercalcemia. This phenomenon of ST elevation secondary to hypercalcemia has been described only two times in the English literature to date.