The Emergency Department Electrocardiogram and Hospital Complications in Myocardial Infarction Patients

Objective: To determine whether acute myocardial infarction (AMI) patients who have negative ECGs on presentation have significantly lower complication rates than do those AMI patients who have positive ECGs on presentation.
Methods: Retrospective, cohort analysis comparing rates of hospital complications (ventricular fibrillation or tachycardia, shock, atrial arrhythmia or bradyarrhythmia with systolic blood pressure 90 mm Hg, pulmonary edema) or interventions among patients with a final hospital diagnosis of AMI and an initially negative vs positive ECG. A negative ECG was normal or had nonspecific ST–segment and/or T–wave abnormalities (upright, flattened T waves; an isolated inverted T wave; ST depression <0.1 mV; tall T waves with J–point elevation) or minor nonischemic abnormalities. Sample size was adequate to detect a 30% between–group difference in complication rates [α = 0.05, 1 —- β (power) = 0.80].
Results: The 27 negative–ECG AMI patients differed from the 38 control patients in (mean X SD) age [57 X 12 vs 66 X 12 years, p < 0.01] but not in gender or history of AMI. The negative– and positive–ECG groups had similar rates of hospital complications [30% (95% CI: 13–47%) vs 42% (95% CI: 26–58%), p = 0.44] and intensive procedures [19% (95% CI: 4–34%) vs 29% (95% CI: 15–43%), p = 0.50], respectively. The negative–ECG patients with hospital complications had ECG evolution precede the event in 83% (95% CI: 69–97%) of cases; persistently negative–ECG patients had no complication [(95% CI: 0–33%), p = 0.06].
Conclusions: Negative– and positive–ECG AMI patients do not have moderate or large differences in the rates of in–hospital complications. Most negative–ECG patients who suffer complications evolve ECG changes prior to the event and such changes indicate the potential need for a higher level of care.     

基层医院远程胸痛急救会诊终端的建设与实践

急性非创伤性胸痛具有起病急骤、病情进展快、诊断困难、可救治时间短等特点。胸痛中心和基层医院远程胸痛急救会诊终端的建立,通过早期启动和快速安全转运,提高了基层医院急诊科对急性胸痛患者的诊治效率。     

Emergency-department Diagnosis of Acute Myocardial Infarction and Ischemia: A Cost Analysis of Two Diagnostic Protocols

Objective:To assess the potential cost savings of the emergency-department (ED) diagnosis of acute myocardial infarction (AMI) and other myocardial ischemia using a nine-hour ED evaluation protocol.
Methods:This one-year study of chest-pain evaluation unit (CPEU) patient charges was undertaken at two midwestern urban university hospital EDs. Included in the study were 447 patients presenting to the EDs with chest pain consistent with myocardial ischemia, nondiagnostic electrocardiograms (ECGs), and stable vital signs. Following initial ED evaluation, CPEU patients underwent nine hours of continuous ECG ST-segment monitoring with serum CK-MB levels determined at zero, three, six, and nine hours. Nonrandomized concurrent chest pain patients with routine ED evaluation and hospital admission without CPEU workup served as controls. At Center 1, patients with negative CPEU evaluations underwent immediate echocardiography (echo) and graded exercise testing (GXT) followed by ED release (CPEU;REL). At Center 2, CPEU patients were released from the ED for outpatient stress thallium testing (CPEU; REL). At Center 2, CPEU patients with positive workups as indicated by elevated CK-MB levels, ischemia by ST-segment monitoring, or positive echo/GXT/stress thallium testing were admitted to the hospital for further testing. Control patients were admitted directly to the hospital to evaluate for AMI. Hospital charges for CPEU and control groups were compared.
Results:(Total charges in dollars, mean ± SD, Student's t-test):
Conclusion:At both centers, hospital charges related to the acute evaluation of chest pain were significantly lower with this ED diagnostic protocol for AMI and myocardial ischemia.     

Prospective Validation of a Modified Thrombolysis In Myocardial Infarction Risk Score in Emergency Department Patients With Chest Pain and Possible Acute Coronary Syndrome

Objectives: This study attempted to prospectively validate a modified Thrombolysis In Myocardial Infarction (TIMI) risk score that classifies patients with either ST‐segment deviation or cardiac troponin elevation as high risk. The objectives were to determine the ability of the modified score to risk‐stratify emergency department (ED) patients with chest pain and to identify patients safe for early discharge. Methods: This was a prospective cohort study in an urban academic ED over a 9‐month period. Patients over 24 years of age with a primary complaint of chest pain were enrolled. On‐duty physicians completed standardized data collection forms prior to diagnostic testing. Cardiac troponin T‐values of >99th percentile (≥0.01 ng/mL) were considered elevated. The primary outcome was acute myocardial infarction (AMI), revascularization, or death within 30 days. The overall diagnostic accuracy of the risk scores was compared by generating receiver operating characteristic (ROC) curves and comparing the area under the curve. The performance of the risk scores at potential decision thresholds was assessed by calculating the sensitivity and specificity at each potential cut‐point. Results: The study enrolled 1,017 patients with the following characteristics: mean (±SD) age 59.3 (±13.8) years, 60.6% male, 17.9% with a history of diabetes, and 22.4% with a history of myocardial infarction. A total of 117 (11.5%) experienced a cardiac event within 30 days (6.6% AMI, 8.9% revascularization, 0.2% death of cardiac or unknown cause). The modified TIMI risk score outperformed the original with regard to overall diagnostic accuracy (area under the ROC curve = 0.83 vs. 0.79; p = 0.030; absolute difference 0.037; 95% confidence interval [CI] = 0.004 to 0.071). The specificity of the modified score was lower at all cut‐points of >0. Sensitivity and specificity at potential decision thresholds were: >0 = sensitivity 96.6%, specificity 23.7%; >1 = sensitivity 91.5%, specificity 54.2%; and >2 = sensitivity 80.3%, specificity 73.4%. The lowest cut‐point (TIMI/modified TIMI >0) was the only cut‐point to predict cardiac events with sufficient sensitivity to consider early discharge. The sensitivity and specificity of the modified and original TIMI risk scores at this cut‐point were identical. Conclusions: The modified TIMI risk score outperformed the original with regard to overall diagnostic accuracy. However, it had lower specificity at all cut‐points of >0, suggesting suboptimal risk stratification in high‐risk patients. It also lacked sufficient sensitivity and specificity to safely guide patient disposition. Both scores are insufficiently sensitive and specific to recommend as the sole means of determining disposition in ED chest pain patients. ACADEMIC EMERGENCY MEDICINE 2010; 17:368–375 © 2010 by the Society for Academic Emergency Medicine     

Differences between Chest Pain Observation Service Patients and Admitted "Rule-out Myocardial Infarction" Patients

Objective: To compare and contrast the patient characteristics of ED patients at low risk for acute cardiac ischemia who were assigned to a chest pain observation service vs those admitted to a monitored inpatient bed for "rule-out acute myocardial infarction" (R/O MI).
Methods: This was a retrospective, cross-sectional comparison of adult patients considered at relatively low risk for cardiac ischemia and who were evaluated in 1 of 2 settings: a short-term observation service and an inpatient monitored bed. All patients had an ED final diagnosis of "chest pain," "R/O MI," or "unstable angina" during the 7-month study period. Demographic features and presenting clinical features were examined as a function of site of patient evaluation.
Results: Of 531 study patients, 265 (50%) were assigned to the observation service. Younger age (OR = 1.75, 95% CI 1.26, 2.44, for each decrement of 20 years), the complaint of "chest pain" (OR = 2.35, 95% CI 1.34, 4.12), and the absence of prior known coronary artery disease (OR = 1.64, 95% CI 1.13, 2.38) were the principal independent factors associated with assignment to a chest pain observation service bed. Conclusions: Patients evaluated in a chest pain observation service appear to have different clinical characteristics than other individuals admitted to a monitored inpatient bed for "R/O MI." Investigators should address differences in clinical characteristics when making outcome comparisons between these 2 patient groups.     

急诊静脉溶栓救治急性心肌梗塞

目的:探讨在急诊室开展静脉溶栓治疗急性心肌梗塞(AMI)的疗效及安全性。方法:对76例AMI患者随机地分为尿激酶组(UK组)与对照组各38例。UK组在常规治疗的基础上选用国产UK150万U溶于0.9％的生理盐水100ml中30min静脉滴入。对照组为常规治疗。又将UK组根据开始溶栓距发病时间分为<3h、3～6h、<6h及6～12h的4个亚组。结果:冠脉再通率:总再通率UK组极显著优于对照组(57.9％与18.4％,P<0.005),UK组的亚组中,<3h者显著优于3～6h者(77.3％与37.5％,P<0.05),<6h显著优于6～12h者(66.7％与25％,P<0.05)。治疗3周时,原梗塞区R波存在例数:UK组极显著优于对照组,(42％与13％,P<0.01);异常O波导联未增加例数:UK组显著优于对照组,(47％与20％,P<0.05);心功能改善:UK组极显著优于对照组(5.3％与28.9％,P<0.01);病死率:UK组低于对照组(10.5％与15.8％,P>0.05),并低于本院开展溶栓治疗前的14％(P>0.05)。UK的副作用仅为轻度出血,无1例死于出血及严重再灌注性心律失常,溶栓及抗凝后再转入病房途中无1例危险事件发生。结论:在急诊室内开展紧急静脉溶栓治疗急性心肌梗塞有效,安全。     

地佐辛治疗急性心肌梗死胸痛疗效观察

【目的】观察地佐辛（Dezocine）治疗急性心肌梗死所引起的胸痛的临床疗效及安全性。【方法】选择急性心肌梗死持续胸痛患者50例,在常规治疗的基础上,随机分为地佐辛与吗啡组各25例,分别采用地佐辛或吗啡给予镇痛治疗。采用疼痛模拟评分（VAS）评定镇痛效果,统计不良反应发生情况。【结果】地佐辛与吗啡组VAs评分在各时点无统计学差异（P〉0．05）,不良反应发生率地佐辛组明显低于吗啡组,两组间比较有统计学差异（P〈0．05）。【结论】地佐辛治疗急性心肌梗死引起的持续胸痛效果明显且副作用较少,安全性较好。     

低血钾与急性心肌梗死冠脉病变程度及预后的关系

[目的]探讨低血钾与急性心肌梗死冠脉病变程度及预后的关系.[方法]根据心肌梗死初期血钾将100例急性心肌梗死患者分为两组:A组血钾＜3.5 mmol/L;B组血钾≥3.5 mmol/L.将两组冠脉造影结果及预后进行比较分析.[结果]A组梗死相关血管近端病变41例(占82%)、梗死相关血管为前降支为27例(占54%)、心力衰竭10例(占20%)、严重心律失常23例(占46%)、梗死后心绞痛14例(占28%),与B组分项比较差异显著.[结论]急性心肌梗死合并低血钾的梗死相关血管多为前降支,梗死相关血管多为近端病变,预后不好.     

Serial Creatine Kinase-MB Results Are a Sensitive Indicator of Acute Myocardial Infarction in Chest Pain Patients with Nondiagnostic Electrocardiograms: The Second Emergency Medicine Cardiac Research Group Study

Objective : To determine the test performance characteristics of serial creatine kinase-MB (CK-MB) mass measurements for acute myocardial infarction (MI) in patients presenting to the ED with chest pain and nondiagnostic ECGs. Methods : A prospective, observational test performance study was conducted. Hemodynamically stable patients aged ≥25 years with chest discomfort, but without ECGs diagnostic for MI, were enrolled at 7 university teaching hospitals. Presenting ECGs showing >1-mV ST-segment elevation in ≥2 electrically contiguous leads were considered diagnostic for MI; patients with diagnostic ECGs on presentation were excluded. Real-time, serial CK-MB mass levels were obtained using a rapid serum immunochernical assay at the time of ED presentation (0-hour) and 3 hours later (3-hour). The following testing schemes were evaluated for their sensitivity and specificity for detection of MI during patient evaluation in the ED: 1) an elevated (≥8 ng/mL) presenting CK-MB level; 2) an elevated presenting and/or 3-hour CK-MB level; 3) a significant increase (i.e., ≥3 ng/mL) within the range of normal limits for CK-MB concentrations during the 3-hour period (A CK-MB); andor 4) development of ST-segment elevation during the 3 hours (second ECG). Results : Of the 1,042 patients enrolled, 777 (74.6%) were hospitalized, including all 67 MI patients (8.6% of admissions). As a function of duration of time in the ED, the test performance characteristics of serial CK-MBs for MI (and cumulative data for the additional ECG) were: 0-hour CK-MB Plus 3-hour CK-MB Plus A CK-MB Plus Second ECG Sensitivity 38/67 = 57% 59/67 = 88% 62/67 = 93% 64/67 = 96% (95% CI) (44–69%) (78–95%) (83–98%) (88–99%) Specificity 9431976 = 97% 9351976 = 96% 9291976 = 95% 9311976 = 95% (95% CI) (95–98%) (94–97%) (94–96%) (94–97%) The 0-hour to 3-hour CK-MB positive and negative predictive values were 52% to 55% and 96% to 99%, respectively. The sensitivities of serial CK-MB results as a function of the interval following chest discomfort onset were: Interval Since Onset Sensitivity (95% CI) Interval Since Onset Sensitivity (95% CI) Less than 3 hours 38% (21–58%) 6 hours to 12 hours 92% (78–98%) 3 hours to 6 hours 75% (60–87%) More than 12 hours 100% (77–100%) Conclusion : Serial CK-MB monoclonal antibody mass measurements in the ED can identify MI patients with initially nondiagnostic ECGs. CK-MB sensitivity significantly increases over 3 hours of observation of stable chest discomfort patients in the ED; it also increases as a function of the total interval from onset until enzyme measurement.     

基层医院开展急诊经皮冠状动脉支架植入术治疗急性心肌梗死的可行性研究

目的：探讨基层医院开展急诊经皮冠状动脉支架植入术（PCI）治疗急性心肌梗死（AMI）的可行性、安全性。方法：回顾分析2002年11月～2009年4月我院41例AMI患者的急诊PCI资料。结果：41例AMI患者,急诊开通梗死相关动脉（IRA）39例（即时成功率95.1%）,开通IRA者中术后死亡2例（死亡率4.9%）,总成功率90.2%。结论：在有条件的基层医院开展急诊PCI安全有效。     

Acute Pain and Availability of Analgesia in the Prehospital Emergency Setting in Italy: A Problem to be Solved

Objectives:   The treatment of acute pain in the prehospital emergency setting remains a significant problem. We evaluated the incidence, site, and possible cause of acute pain in the prehospital period and also the current state of prehospital pain management by evaluating analgesic availability in emergency vehicles in Italy.
Methods:   First aid volunteers documented the presence, intensity, and site of acute pain by questionnaire for over 3 months. Emergency service operations completed a questionnaire on analgesic availability in ambulances and helicopters.
Results:   Pain symptoms were present in two-thirds of the patients ( n  = 383) and ranked as moderate to unbearable in 41.75%. Results of the analgesic availability survey indicate that 10.6% of the ambulance services carry no pain killers (including non-steroidal anti-inflammatory drugs [NSAIDs] and/or paracetamol) and 11.5% are without an opioid. The emergency helicopter survey showed a significant difference in analgesic availability compared with ambulances, with 97.6% having at least one opioid agent available (weak or strong). A wide geographical variation in the availability of analgesic agents in ambulance and helicopter services was seen.
Conclusions:   There is a high prevalence of pain among patients receiving prehospital emergency treatment in Italy and treatment for acute pain during emergency treatment of trauma patients is inadequate. All emergency vehicles, without distinction, should carry opioids and other analgesic drugs (NSAIDs and paracetamol) and there should be no geographic differences in the availability of pain medications.     

How Useful Are Clinical Features in the Diagnosis of Acute,Undifferentiated Chest Pain?

OBJECTIVES: To measure the predictive value and diagnostic performance of clinical features used to diagnose coronary syndromes in patients presenting with acute, undifferentiated chest pain. METHODS: The clinical features of patients presenting to the authors' chest pain unit with acute, undifferentiated chest pain were prospectively recorded on a standard form. Admitted patients were followed up by case note review. Discharged patients were followed up as outpatients three days later. Six months after the emergency department visit, evidence of adverse events was searched for from the hospital computer database, case notes, and the patient's primary care physician. The authors tested the power of each feature to predict: 1) acute myocardial infarction (AMI) by World Health Organization criteria, and 2) any acute coronary syndrome (ACS), evidenced by cardiac testing, AMI, arrhythmia, death, or revascularization procedure within six months. RESULTS: Eight hundred ninety-three patients were assessed, 34 (3.8%) with AMI and 81 (9.1%) with ACS. Features useful in the diagnosis of AMI were exertional pain [likelihood ratio (LR) = 2.35], pain radiating to the shoulder or both arms (LR = 4.07), and chest wall tenderness (LR = 0.3). Features useful in the diagnosis of ACS were exertional pain (LR = 2.06) and pain radiating to the shoulder, the left arm, or both arms (LR = 1.62). The site or nature of pain and the presence of nausea, vomiting, or diaphoresis were not predictive of AMI or ACS. CONCLUSIONS: Important differences exist when clinical features are specifically investigated in patients with acute chest pain and a nondiagnostic electrocardiogram. Clinical features have a limited role to play in triage decision making.     

Prognosticating Clinical Prediction Scores Without Clinical Gestalt for Patients With Chest Pain in the Emergency Department

Background

Assessment of patients with chest pain is a regular challenge in the emergency department (ED). Recent guidelines recommended quantitative assessment of ischemic risk by means of risk scores.

Adverse Cardiac Events in Emergency Department Patients with Chest Pain Six Months after a Negative Inpatient Evaluation for Acute Coronary Syndrome

OBJECTIVE: To evaluate the impact of the diagnostic test setting-inpatient versus outpatient-on adverse cardiac events (ACEs) after six months in emergency department (ED) patients with chest pain who were admitted to the hospital and subsequently had a negative evaluation for acute coronary syndrome (ACS). METHODS: The authors retrospectively studied a consecutive sample of ED patients with chest pain over a nine-month period. All patients were admitted to the hospital and underwent negative evaluations for ACS, defined as the absence of diagnostic changes on serial electrocardiograms or cardiac markers (creatine kinase-MB and troponin T), and a negative diagnostic cardiac study. Subjects were classified according to cardiac diagnostic study setting-either inpatient or outpatient. Diagnostic testing included exercise treadmill, angiography, stress echocardiography, or stress thallium scans. Acute cardiac events at six months were defined as cardiac death, myocardial infarction, unstable angina, cardiac arrest, or emergent revascularization. RESULTS: The six-month rate of ACEs among 157 subjects was 14%, with 2% cardiac mortality. The outpatient group had higher ACE risk when compared with the inpatient group using multivariate logistic regression, both for the entire cohort (OR 3.5, p < 0.03) and for a subgroup excluding patients with prior coronary artery disease (OR 6.7, p < 0.05). The outpatient group included 19 of 52 (37%) noncompliant subjects who did not receive a diagnostic study. CONCLUSIONS: Long-term cardiac morbidity of patients after a negative ACS evaluation may be higher than previously thought. Risk of ACE is significantly higher in subjects scheduled for outpatient diagnostic tests. Inpatient diagnostic testing is justified for subjects at risk for poor compliance.     

Congestive Heart Failure Patients with Chest Pain: Incidence and Predictors of Acute Coronary Syndrome

OBJECTIVE: New diagnostic and treatment options for emergency department (ED) patients with congestive heart failure (CHF) may facilitate the ED discharge of some patients. However, some patients require admission to exclude concurrent acute coronary syndrome (ACS) as the precipitant of CHF. The objective of this study was to identify the incidence, clinical characteristics, and hospital course of CHF patients who present to the ED with and without concurrent ACS. METHODS: This was a prospective cohort study of consecutive patients >23 years of age who presented to the ED with chest pain, received an electrocardiogram (ECG), and either had a known history of CHF or presented with new-onset CHF, between July 1999 and April 2001. The hospital course of each patient was followed daily, and telephone follow-up occurred at 30 days. The main outcomes were the incidence of ACS and comparisons of lengths of hospital stay (LOSs), rates of admission to the intensive care unit (ICU), intubations, and death rates among patients with and without ACS. RESULTS: Two hundred ninety-eight CHF patients presented 380 times. The incidence of ACS in the 380 patient visits was 32% (95% CI = 27% to 36%). Compared with patients who did not have ACS, patients who had concurrent ACS were more likely to have known coronary artery disease (CAD) (67% vs. 42%; p < 0.0001) and hypercholesterolemia (36% vs. 18%; p = 0.0002). Patients with concurrent ACS were also more likely to be admitted to the hospital (97% vs 82%; p < 0.0001), had a longer LOS (5.2 [3.9-6.5] vs 3.2 [2.6-3.8] days; p = 0.006), had higher rates of ICU admission (44% vs. 13%; p < 0.0001), were more likely to be intubated (8% vs. 1%, p = 0.002), and were more likely to die (15 vs 7 deaths; p < 0.0001). CONCLUSIONS: The incidence of ACS in ED CHF patients with chest pain was 32%. Patients with CHF complicated by ACS had more prolonged hospital stays, required higher levels of care, and had a higher incidence of death than those patients without ACS. Strategies tailored to early identification and management of these patients would be desirable.