Pitfalls in the emergency department diagnosis of acute myocardial infarction

The accurate assessment and triage of patients with potential ACS is a complex decision-making process based on information that is not entirely reliable. The knowledgeable EP recognizes that assessment of patients with chest pain requires an understanding of the various clinical presentations of ACS and high-risk patient types, as well as careful use of the available modalities to diagnose these syndromes efficiently while incurring minimal risk to the patients safety. The busy EP is faced with sick patients with chest pain daily, so that it behoove anyone in emergency medicine to familiarize themselves with these diagnostic pitfalls.     

Biochemical markers in the management of suspected acute myocardial infarction in the emergency department

Objectives—To compare cardiac troponin T, myoglobin, CK, CKMB activity, CKMB mass and the initial electrocardiogram in the early diagnosis of myocardial infarction in the emergency department.

Methods—Biochemical markers were measured at presentation in patients with a possible diagnosis of acute myocardial infarction. Based on the clinical notes, patients were grouped as "definite myocardial infarction" (n = 50), "definite no myocardial infarction" (n = 81) and "uncertain" (n = 96). Sensitivity and specificity and positive and negative predictive values were calculated using the 131 patients with definitely present or absent myocardial infarction.

Results—The initial electrocardiogram was more sensitive than any of the markers in the first six hours from symptom onset—sensitivity 74% (95%CI 61% to 88%). The positive predictive value of the initial electrocardiogram was 97% in the first six hours; the markers ranged from 47% to 67%. The negative predictive value of the initial electrocardiogram was 85% in the first six hours; the markers ranged from 61% to 70%. Four patients with non-diagnostic electrocardiograms presenting beyond six hours after pain onset had a myocardial infarct detected by at least three of the biochemical markers in each case.

Conclusions—The electrocardiogram is of more diagnostic use than biochemical markers in the first six hours after the onset of pain, but biochemical markers give additional positive diagnostic information in patients presenting later than this. The negative predictive accuracy of biochemical markers is too low for a single sample to be useful for excluding myocardial infarction in the first six hours after onset of symptoms.

     

Body surface mapping improves diagnosis of acute myocardial infarction in the emergency department

Traditionally, the diagnosis of acute myocardial infarction (AMI) in emergency departments is done through an assessment of history and presenting symptoms, 12-lead electrocardiogram (ECG), and cardiac biomarkers. The 12-lead ECG is not highly sensitive for detecting ECG changes, and some infarctions may be missed. Failure to identify patients in the early stages of AMI can result in failure to provide beneficial therapies. New technology, the 80-lead ECG, uses body surface mapping to provide a more comprehensive view of cardiac electrical activity. Body surface mapping has greater sensitivity in detecting AMI in the inferoposterior portions of the left ventricle and the right ventricle. Portable hardware and user-friendly software coupled with an easily applied disposable torso vest containing the electrodes produce a 12-lead ECG, 80-lead ECG, and color contour torso or flat map showing ECG changes. Recent studies support the use of 80-lead body surface mapping for detecting AMI in the emergency department.     

The diagnosis of acute myocardial infarction in the emergency department; Part 2.

At present, routine use of cardiac enzymes in the emergency department (ED) cannot be justified, except possibly as a final screen prior to discharge. Computer-derived predictive instruments do not surpass the physician's diagnostic sensitivity for acute myocardial infarction (AMI), but do demonstrate significantly higher specificity. Limited data exist on the utility of echocardiography and thallium scanning in the ED. Methods of triaging patients on the basis of prognosis are well supported in the literature. The physician's high diagnostic sensitivity is maintained at the cost of significant numbers of admissions who subsequently rule out for AMI. No single clinical variable or combination of clinical variables can reliably confirm or exclude AMI in the ED. Ultimately, the physician's clinical assessment must remain the final determinant of the necessity for admission. However, judicious use of prediction rules and prognostic indicators should improve resource utilization.     

The diagnosis of acute myocardial infarction in the emergency department; Part 1.

Despite major advances in treatment, the accurate diagnosis of acute myocardial infarction (AMI) in the emergency department (ED) remains a difficult clinical problem and is still mainly based on the history and interpretation of the electrocardiogram. Although the physician's clinical impression is a highly sensitive indicator for AMI, at least 4% of patients presenting to the ED with AMI may be mistakenly sent home. Although chest pain is the most common chief complaint, the clinical presentation can be extremely variable, particularly in the elderly. Complaints of sharp chest pain or chest wall tenderness should not be relied upon to exclude AMI. Radiation of chest pain is an important symptom. With careful analysis, the electrocardiogram may yield a higher diagnostic sensitivity than is commonly accepted.     

High-sensitivity versus conventional troponin in the emergency department for the diagnosis of acute myocardial infarction

Introduction  

Recently, newer assays for cardiac troponin (cTn) have been developed which are able to detect changes in concentration of the biomarker at or below the 99th percentile for a normal population. The objective of this study was to compare the diagnostic performance of a new high-sensitivity troponin T (HsTnT) assay to that of conventional cTnI for the diagnosis of acute myocardial infarction (AMI) according to pretest probability (PTP).     

Prognostic significance of interleukin-6 measurement in the diagnosis of acute myocardial infarction in emergency department

BACKGROUND: Markers of inflammation may predict both coronary artery disease (CAD) and adverse outcomes in patients with known CAD. Here, we investigated the role of interleukin-6 (IL-6) in the "triage" and risk assessment of patients admitted to emergency department (ED). METHODS: Serum IL-6 and high sensitivity C-reactive protein (hs-CRP) levels were prospectively evaluated in 88 patients with a history of precordial chest pain or shortness of breath of recent onset (<6 h). RESULTS: Of the 88 patients, 21% were discharged from the ED with diagnosis of non-ischemic chest pain (NICP), 39% had a final diagnosis of unstable angina (UA) and 40% experienced an acute myocardial infarction (AMI). Median IL-6 (p<0.001) and hs-CRP (p<0.01) levels on admission were significantly increased in patients with AMI compared with patients with NICP or UA. IL-6 levels correlated with hs-CRP (p<0.01). Multivariate analyses including known risk factors showed that elevated creatine kinase-MB (p<0.05) and IL-6 levels (p<0.01) were independently associated with a final diagnosis of AMI. Elevated IL-6 levels significantly predicted the risk of AMI (OR=2.47, p=0.006) in chest pain-enzyme negative patients. CONCLUSIONS: IL-6 may behave as an adjunctive diagnostic tool to assist in the risk assessment of enzyme-negative patients with precordial chest pain of recent onset.     

Therapeutic procedures in the emergency department patient with acute myocardial infarction

Life-threatening cardiac arrhythmias and other peri-infarct complications are often unexpected and commonly present with little warning. The therapeutic procedures reviewed often require immediate implementation and should be second nature to any physician involved in the management of patients with an AMI.     

Performance of a sensitive troponin assay in the early diagnosis of acute myocardial infarction in the emergency department

Aim: Troponin assays have high diagnostic value for myocardial infarction (MI), but sensitivity has been weak early after chest pain onset. New, so‐called ‘sensitive’ troponin assays have recently been introduced. Two studies report high sensitivity for assays taken at ED presentation, but studied selected populations. Our aim was to evaluate the diagnostic performance for MI of a sensitive troponin assay measured at ED presentation in an unselected chest pain population without ECG evidence of ischaemia. Methods: This is a sub‐study of a prospective cohort study of adult patients with potentially cardiac chest pain who underwent evaluation for acute coronary syndrome. Patients with clear ECG evidence of acute ischaemia or an alternative diagnosis were excluded. Data collected included demographic, clinical, ECG, biomarker and outcome data. A ‘positive’ troponin was defined as >99th percentile of the assay used. MI diagnosis was as judged by the treating cardiologist. The outcomes of interest were sensitivity, specificity and likelihood ratios (LR) for positive troponin assay taken at ED presentation. Data were analysed by clinical performance analysis. Results: Totally 952 were studied. Median age was 61 years; 56.4% were male and median TIMI score was 2. There were 129 MI (13.6, 95% CI 11.5–15.9). Sensitivity of TnI at ED presentation was 76.7% (95% CI 68.5–83.7%), specificity 93.6% (95% CI 91.7–95.1%), with LR positive 11.92 and LR negative 0.25. Conclusion: Sensitive TnI assay at ED presentation has insufficient diagnostic accuracy for detection of MI. Serial biomarker assays in patients with negative initial TnI are required.     

急诊室内使用瑞替普酶治疗急性心肌梗死的疗效评价

目的比较第三代静注溶栓药物瑞替普酶(rPA)和阿替普酶(rt-PA)对急性心肌梗死(AMI)患者急诊静脉溶栓治疗的临床疗效。方法采用前瞻开放性临床研究方法,观察2004年3月至2006年12月期间在本院急诊室内接受rPA或rt-PA静脉溶栓治疗的AMI患者,共55例,其中rPA组24例,rt-PA组31例,观察血管再通率、死亡率、平均住院天数、心力衰竭及休克等并发症和出血不良反应。结果rPA和rt-PA组的再通率分别为87.50%和83.83%,(P>0.05)。溶栓后30d内心力衰竭、休克及再梗死发生率两组相当,(P>0.05);死亡率分别为8.33%(2例)和6.45%(2例),P>0.05;轻度出血发生率分别66.66%和48.38%,P>0.05;脑出血发生率为8.33%和9.68%,P>0.05;住院天数分别为(10.74±6.49)d和(13.09±13.36)d,P>0.05。结论瑞替普酶适合急诊室内急性心肌梗死患者的静脉溶栓治疗。     

Effects of EMS transportation on time to diagnosis and treatment of acute myocardial infarction in the emergency department

INTRODUCTION. Recent studies have documented decreased time to emergency department (ED) thrombolytic therapy with the use of prehospital electrocardiography. PURPOSE. Is the time to ED diagnosis and treatment of acute myocardial infarction (AMI) patients with thrombolytic agents decreased by emergency medical services (EMS) transport when compared with those transported by other means (non-EMS)? DESIGN. Retrospective, case-control study. POPULATION. The AMI patients treated with thrombolytic agents at a 34,000-visit, community hospital ED during 1992. METHODS. Review of records of patients who received thrombolytic therapy for AMI. Statistical analysis was performed using "Student's" t-test and Yates corrected Chi-square. RESULTS. Eighty-seven patients received thrombolytic agents for AMI during 1992; 33 arrived by ambulance, 54 arrived by other methods. There were no differences in age, gender, or time of ED arrival among these groups. Ambulance patients received standard advanced life support (ALS) care, but not a 12-lead electrocardiogram (ECG) or thrombolytic agents. Ambulance patients experienced a significantly shorter time to first ECG (12.9 +/-9.1 min. versus 20.8 +/-25.3 min.; p = .028) and received thrombolytic therapy sooner than did controls (56.0 +/-31.5 min. versus 78.0 +/-63.4 min.; p = .018). There was no difference in time from diagnosis to treatment between these groups. CONCLUSION. Emergency medical services transport of AMI patients in this study decreased time to diagnosis and treatment and may be a confounder in studies that assess the value of field EMS interventions.(ABSTRACT TRUNCATED AT 250 WORDS)     

心肌损伤标志物联合检测在急性心肌梗死诊断中的价值

目的评价心肌损伤标志物肌钙蛋白T/I(cTnT/I)、肌红蛋白(Myo)、肌酸激酶同工酶(CK-MB)在急性心肌梗死(AMI)中的诊断价值。方法对150例AMI患者进行心肌标志物和心肌酶谱比较。结果心肌标志物在AMI发病早期升高的幅度较心肌酶谱升高显著,差异有统计学意义(P0.01)。结论心肌损伤标志物cT-nT/I、Myo、CK-MB在AMI早期诊断中具有重要的临床价值。     

心肌标志物联合检测在急性心肌梗死早期诊断中的应用价值

目的探讨高敏C反应蛋白(hs-CRP)、肌钙蛋白I(cTnI)和肌酸激酶同工酶(CK-MB)联合检测在心肌梗死早期诊断中的应用。方法选取2010年1月至2013年12月荆门市第一人民医院收治的2型糖尿病伴心肌梗死住院患者106例,其中60例具有典型心肌梗死症状的患者纳入对照组,46例不典型心肌梗死患者纳入观察组,动态监测两组患者发病后血清hs-CRP、cTnI、CK-MB水平的变化,并比较不同时间点两组患者各指标水平。结果不同时间点两组患者血清hs-CRP、cTnI、CK-MB水平比较,差异均无统计学意义(P0.05);两组患者血清CK-MB水平均于发病后3~12h开始升高,24~48h达到高峰,3~5d基本恢复正常水平;血清hs-CRP水平于发病后3h开始升高,一直保持高水平,3~5d后开始下降;血清cTnI水平于发病后3~6h开始升高,12~24h达高峰,一直持续高水平,5d后开始下降。结论 CK-MB、hs-CRP及cTnI联合检测有助于心肌梗死的早期诊断,尤其可提高症状不明显患者的诊断率,避免漏诊、误诊。     

Beta-blocker use in the emergency department in patients with acute myocardial infarction undergoing primary angioplasty

Our objectives were to evaluate the frequency of β-blocker administration in the setting of acute myocardial infarction (AMI) where angioplasty is the primary treatment, and to investigate Emergency Physician’s (EPs) attitudes toward β-blockers. We performed a retrospective chart review of all patients who presented with symptoms and electrocardiogram (EKG) criteria consistent with AMI in the defined study period. Charts were reviewed for β-blocker administration and other treatments. A survey was subsequently distributed to all EPs to determine self-reported reasons for withholding β-blockers. There were 91 patients identified. Of those who did not have contraindications, 99% (89/90) received aspirin, 97% (88/91) received heparin, 94% (84/89) received nitrates, but only 28% (19/68) received β-blockers. Ninety-six percent of β-blocker-eligible patients received them as inpatients. Eighty-six percent (44/52) of EPs completed the survey. Physicians felt strongly about avoiding β-blockers in patients with asthma exacerbation, severe congestive heart failure, and high degree AV block. Bradycardia was the most frequent reason for withholding β-blockers. In this series of patients presenting with AMI, β-blockers were greatly underutilized. The self-reported reasons of EPs for withholding β-blocker therapy did not explain why 72% (49/68) of patients without contraindications did not receive β-blockers.     

急诊应用瑞替普酶尿激酶对急性心肌梗死溶栓的随机对照研究

目的 在急诊科观察瑞替普酶(r-PA)、尿激酶(UK)用于急性心肌梗死(AMI)溶栓治疗的疗效和不良反应.方法 对符合入选标准的87例AMI患者随机分为r-PA组和UK组,在急诊科分别给予r-PA和UK溶栓治疗,其中r-PA组41例,UK组46例,观察两组溶栓后相关冠状动脉再通率,急性期35 d内的死亡率、并发症和不良反应发生率.结果 2 h内溶栓再通率r-PA组36例(87.8%),UK组30例(65.2%),两组比较差异有统计学意义(P<0.05);两组在急性期35 d内死亡率、缺血再发生和并发症比较差异无统计学意义(P>0.05);r-PA组出血不良反应少于UK组,两组比较差异有统计学意义(P<0.05).结论 与UK相比,在急诊室给予AMI患者r-PA溶栓治疗,梗死相关动脉再通率更高,出血不良反应较少.     

心肌损伤标志物联合检测在急性心肌梗死早期诊断中的价值

目的探讨心肌损伤标志物血清缺血修饰蛋白(IMA)、肌红蛋白(Mb)和正常对照组肌钙蛋白I(cTnI)联合检测在急性心肌梗死(AMI)早期诊断中的临床应用价值。 方法选择2015年1月至2017年12月于高唐县人民医院急诊科、心内科就诊且确诊为AMI的115例患者作为研究组,50例健康体检者作为正常对照组,测定研究组患者入院0.5 h、6 h、12 h后及正常对照组血清IMA、Mb和cTnI水平,并进行统计学分析,比较血清IMA、Mb和cTnI对AMI早期诊断的敏感度、特异度、准确度。通过受试者工作特征(ROC)曲线下面积(AUC)比较各指标在AMI早期诊断中的价值。 结果在患者入院0.5 h、6 h、12 h后,研究组血清IMA水平[(128.35±13.53)U/ml,(104.27±11.64)U/ml,(84.73±6.97)U/ml]、Mb水平[(161.83±15.64)μg/L,(311.44±40.92)μg/L,(470.45±46.81)μg/L],cTnI水平[(0.31±0.05)μg/L,(12.56±2.73)μg/L,(74.84±6.37)μg/L],与对照组血清IMA、Mb和cTnI水平[(32.34±3.57)U/ml,(51.47±8.53)μg/L,(0.27±0.03)μg/L]比较,均差异有统计学意义(F＝65.42,52.21,67.46;均P<0.01)。在患者入院12 h后,IMA、Mb和cTnI诊断AMI的敏感度分别为80.58%、86.65%、59.63%,特异度分别为45.14%、34.57%、88.32%,准确度分别为72.81%、75.48%、89.56%;IMA＋Mb＋cTnI联合检测的敏感度、特异度、准确度分别为74.34%、91.56%、92.69%。IMA、Mb、cTnI单项检测及IMA＋Mb＋cTnI联合检测诊断AMI的ROC曲线AUC分别为0.618,0.582,0.822,0.914,IMA＋Mb＋cTnI的AUC最大,具有较高的诊断效能,优于IMA、Mb和cTnI单项检测。 结论心肌损伤标志物IMA、Mb和cTnI的联合检测,可为AMI的早期诊断提供更好的参考依据,对早期排除和确定诊断AMI有重要的临床应用价值。     

急性心肌梗死患者血中生化标志物对诊断及心脏功能预后的价值

近几十年来医学科学取得了巨大的进步,在心血管领域涌现出了不少新的诊断技术,特别是在生化标志物方面尤为突出。更敏感、更精确的血清生化标记物的出现,需要对原来心肌梗死的定义进行重新评价,现在能发现过去不能诊断的非常小的心肌梗死灶。心肌梗死诊断标准敏感性的增高,意味着会发现更多的病例。在心肌梗死治疗及康复实践中,迫切需要对疾病发生、病情发展及其危险因素做出及时准确的评估及跟踪评估,以研究制定科学合理的治疗及康复方案,并评价药物治疗及康复治疗的效果及其可能的负面影响。现阶段血清生化标志物的研究与进展,虽尚待进一步深入,但已经为准确判断心肌梗死病情提供了一些较为科学、有效、可行的手段。     

心肌损伤标志物在非Q波型急性心肌梗死早期诊断中的应用

目的探讨心肌损伤标志物在非Q波型急性心肌梗死（AMI）早期诊断中的应用,减少非Q波型AMI误诊的机会。方法通过单克隆金标志双抗免疫渗滤快速分析法,动态观测心肌标志物在非Q波型AMI时的敏感性、特异性、漏诊率及诊断符合率。结果心肌肌钙蛋白I（cTnI）、肌红蛋白（Myo）、肌酸激酶-同工酶质量（CK-MB mass）对非Q波型AMI的相对敏感性为38．3％～85．1％,诊断符合率为62．1％～82．8％,均随时间增加逐渐增高;相对特异性为75．0％～100％,漏诊率为14．9％～61．7％,均随时间增加降低;心肌肌钙蛋白T（cTnT）、cTnI在不同时间均优于CK-MB mass,Myo相对敏感性在6h后迅速从85．1％下降至44．7％、12．8％,漏诊率在6h只有14．9％。结论cTnT、cTnI、Myo、CK-MBmass对非Q波型AMI的早期、快速诊断具有一定价值,其临床应用将减少非Q波型AMI误诊的机会。