Clinical experience with a decision support computer program using Bayes' theorem to diagnose chest pain patients

A decision support computer program (DSP) was used by the emergency room physician as a diagnostic tool on patients admitted with acute chest pain to guide the referral of these patients either to the Coronary Care Unit (CCU) or general ward. The DSP used Bayes' theorem on 38 anamnestic and clinical variables to classify patients into one of nine diagnoses. During a six months trial period 32 physicians used the DSP to diagnose 493 patients admitted with acute chest pain. The physicians referred the patients to CCU or general ward based on their clinical judgements, the ECG findings and the diagnostic estimates given by the DSP. The program correctly diagnosed 150 (84%) of 178 patients with acute myocardial infarction and 63 of 112 patients with unstable angina. However, acute ischemic heart disease (acute myocardial infarction or unstable angina) was correctly classified by the DSP for 259 (89%) of 290 patients. By using the DSP, the number of patients unnecessarily referred to CCU was reduced from 35% to 19% and the number of patients in need of CCU observation misallocated to general ward was reduced from 13% to 10%. Thus, use of the DSP in the emergency room on easily available anamnestic and clinical variables may improve referrals to the CCU, optimize therapy and resource use.     

Does the emergency room electrocardiogram identify patients with suspected myocardial infarction who are at low risk of acute complications?

Abstract To determine the early morbidity of patients admitted to the coronary care unit (CCU) with inconclusive evidence of acute myocardial infarction, the prognostic value of the emergency room electrocardiogram (ECG) was examined prospectively in a blinded fashion in 410 patients presenting with acute chest pain. One hundred and forty one patients (34.4%) had an ECG that was normal, showed ST segment changes < 1 mm, or was unchanged from a previous recording (group 1). The remaining patients (65.6%, group 2) had ECGs considered abnormal. Thirty-nine patients in group 1 and 226 in group 2 had confirmed infarction. There was one CCU death in group 1 (0.7%) versus 27 (10.0%) in group 2 (p<0.001) and the overall hospital mortality for group 1 was 2.1% versus 13.0% in group 2 (p< 0.001). Twenty-eight patients (19.9%) from group 1 suffered complications in the CCU versus 155 (57.6%) from group 2 (p< 0.001). No life-threatening arrhythmias occurred in group 1 versus occurrence in 47 patients (17.5%) in group 2 (p< 0.001). The need for acute intervention was also less for group 1 versus group 2 patients, 14 (9.9%) and 85 (31.6%) respectively (p<0.001) with no patient requiring electrical cardioversion in group 1. It is concluded that the emergency room ECG can reliably identify a group of low risk patients presenting with suspected myocardial infarction and so help in establishing priority for admission to the CCU. Furthermore, the risk-benefit of thrombolytic therapy in these low risk patients appears unacceptable.     

Standardized use of simple criteria from case history improves selection of patients for cardiac-care unit (CCU) admission.

A simple algorithm, which improves the diagnostic performance in patients arriving with acute chest pain in the emergency room, has been developed. The algorithm is solely based on information immediately available to the physician and includes elements from ECG, clinical findings and case history. As postulated, a stepwise use of all these variables improved the diagnostic accuracy and reduced the false positive cardiac-care unit (CCU) referral rate in a prospective study of 1450 patients admitted with acute chest pain. Compared to previous hospital practice during a preceding control period, sensitivity in diagnosing patients with unstable ischaemic heart diseases increased from 86% to 94% (P < 0.01), and specificity increased from 44% to 56% (P < 0.001). Accordingly, accuracy increased from 67% to 81% (P < 0.001), and false positive CCU-admission rate decreased from 35% to 19%. The greatest improvement in physician's diagnostic decisions was observed among patients without clear-cut signs of acute ischaemic heart disease on admission.     

Outcome of patients who were admitted to a new short-stay unit to "rule-out" myocardial infarction

For emergency room patients with a low probability of acute myocardial infarction, we established a new short-stay coronary observation unit, a 2-bed nonintensive care unit with telemetry monitoring adjacent to the emergency room. Of 512 consecutive admissions to the coronary observation unit, 425 (83%) were discharged home without evidence of acute myocardial infarction or serious complications (mean length of stay, 1.2 days; median length of stay, 1 day); 87 (17%) were transferred to other hospital beds. The rate of acute myocardial infarction was 3%. No deaths and only 1 serious complication occurred in the coronary observation unit. At 6 month follow-up, the cardiac survival rate was 99% for patients sent home directly from this unit. It is concluded that the coronary observation unit is safe and adequate for ruling out acute myocardial infarction in a defined subset of patients. Short-stay units, however, encourage early discharges which, when premature, may miss patients who are at risk of having complications shortly thereafter. Strategies such as mandatory but expeditious predischarge stress testing to encourage early but not premature discharge may augment the efficiency of coronary observation units.     

Suspect myocardial infarction: hospital management and prognosis

The management of 442 consecutive patients admitted for suspect acute myocardial infarction (AMI) was compared at two urban hospitals. The community hospital utilized an unmonitored observation unit (OU) more frequently than did the university hospital (39% vs. 9%, respectively). Progression to acute myocardial infarction (AMI) occurred in 25% of admissions, 5-7% of whom died. Mortality without AMI was rare. Availability of the OU appeared to result in reduced coronary care unit (CCU) utilization and in shorter hospital stays for low-risk patients who comprised fully 37% of hospital admissions. Low- and high-risk subgroups (12% vs. 34% risk of AMI) were identified by normal versus abnormal admission electrocardiograms (EKG). Two-thirds of the low-risk patients with AMI were diagnosed by the next hospital day. A normal EKG on both the day of admission and on the second hospital day identified a population with less than 1% risk of in-hospital AMI. The increased use of non-CCU facilities for many ?MI patients appears to be appropriate. However, only randomized allocation trials, which were never performed for patients with definite AMI, would establish the relative efficacy of CCU versus non-CCU treatment.     

Optimal use of coronary care units: A review

Patients at a low probability of acute cardiac pathology constitute a considerable proportion in many coronary care units (CCUs), such that physicians should consider more effective alternatives than CCU admission “to rule out myocardial infarction.” In this article, strategies to increase the efficiency of managing patients with acute chest pain are reviewed. Algorithms aiming to improve the diagnostic accuracy of the general practitioner have been developed but require an electrocardiogram recorded at the home of the patient. Another method of triage encompasses the identification in the emergency room of the hospital of patients at a low probability of acute cardiac pathology by using predictive models that include laboratory assessments. A third strategy includes alternatives to CCUs for patients at a low risk of acute cardiac pathology, such as the creation of a simple observation unit. Finally, some investigators have sought to identify patients with good prognosis for early transfer from the CCU to lower levels of care. It is concluded that a combination of these approaches will be most efficient, and that the most appropriate choice will be determined by local circumstances.     

Direct admission to the coronary care unit by the ambulance service for patients with suspected myocardial infarction

Background—Direct access to the coronary care unit (CCU) for general practitioner (GP) referred cases of suspected acute myocardial infarction (AMI) (fast track admission) substantially reduces the time to thrombolysis. Until now, this policy has been confined to GP referrals.
Objectives—To determine the time taken to admission to CCU under the fast track policy (ambulance referrals and GP referrals) and the time taken to start administration of thrombolytics (ambulance referrals, GP referrals, and accident and emergency referrals).
Methods—Fast track admission policy was extended to include referrals from ambulance personnel who respond to emergency service calls. Ambulance personnel referred cases were also examined to see if they were referred appropriately to the CCU.
Results—100 ambulance personnel referrals and 260 GP referrals to CCU with chest pain were studied. Forty accident and emergency referrals who had AMI requiring thrombolysis were also studied. In the ambulance referred group the time to admission from phone call was a median of 10 minutes (range 2 to 45), a saving of 30 minutes compared with GP referrals (median 40 minutes, range 2 to 217). The median diagnostic electrocardiogram (ECG) to thrombolysis time was longer in the accident and emergency referrals with AMI than either ambulance referrals or GP referrals admitted under the fast track policy. Diagnostic ECG to thrombolysis time: accident and emergency 50 minutes (range 15 to 385); ambulance referrals median 33 minutes (range 6 to 69); GP referrals median 29.5 minutes (range 5 to 110 minutes); (p = 0.056 accident and emergency compared with ambulance referrals, p < 0.002 accident and emergency compared with GP referrals). Of 100 ambulance referrals 52 patients exhibited symptoms suggestive of ischaemic heart disease (confirmed AMI, unstable angina, and angina) and a further 18 patients were required to stay in CCU for other cardiac problems. Thus a total of 70 (70%) were considered appropriate compared with 155 of 260 (55.8%) GP referred cases.
Conclusions—Extending the fast track admission policy to ambulance personnel reduces delay to admission for patients with suspected MI without adversely affecting the appropriateness of admissions.

Keywords: direct admission to coronary care;  time to thrombolysis;  ambulance personnel     

Patients admitted to the emergency room with symptoms indicative of acute myocardial infarction

All 7157 patients (55% men) admitted to the emergency room with chest pain or other symptoms indicative of acute myocardial infarction during a period of 21 months were registered consecutively. Chest pain was reported by 93% of the patients. On the basis of history, clinical examination, and electrocardiogram in the emergency room, all patients were prospectively classified in one of four categories: (i) obvious infarction (4% of all patients); (ii) strongly suspected infarction (20%); (iii) vague suspicion of infarction (35%); and (iv) no suspected infarction (41%). In patients with no suspected infarction (n = 2910), musculoskeletal (26%), obscure (21%) and psychogenic origins (16%) of the symptoms occurred most frequently. We conclude that few of the patients had an obvious infarction on admission, and that a musculoskeletal origin of the symptoms occurred most frequently in patients with no suspected infarction.     

Clinical characteristics,management, and prognosis of patients with acute myocardial infarction not admitted to the coronary care unit. Usefulness of an intermediate care unit as the initial admission site

INTRODUCTION AND OBJECTIVES: There is little information about the management and prognosis of patients with acute myocardial infarction (AMI) who are not admitted to coronary care units (CCU) because of the lack of available beds. The aim of this study was to evaluate the characteristics and prognosis of the patients who were admitted to the intermediate care unit (INTCU) of a cardiology department. METHODS: We compared the clinical profile, management, and 12-month prognosis of the patients admitted to the INTCU or general ward (Ward) instead of the CCU. RESULTS: Out of 242 patients with AMI, 62 (23%) were not admitted to the CCU due to the lack of available beds. Of these, 29 (12%) were admitted to the INTCU and 26 (11%) to the Ward after being monitored for at least 24 h in the emergency room. Patients admitted to the CCU arrived at the hospital early, were younger, less frequently female, and had a lower prevalence of diabetes. ST-segment elevation AMI was more frequent in patients admitted to the CCU than in patients admitted to the INTCU or Ward (67 vs 17 and 23%, respectively; p < 0.0001), and non-Q wave AMI was less frequent (30 vs 76 and 81%; p < 0.0001). No differences were found between groups in the number of stress tests or revascularization procedures performed after the first 24 h, the duration of the hospital stay (median 8 days), or in-hospital mortality. The 12-month survival was 82, 80, and 64% in the patients admitted to the CCU, INTCU, or Ward (p < 0.05), respectively. These differences ceased to be significant after adjusting for the patients' baseline clinical profile and treatment received at admission. CONCLUSION: Compared to patients with AMI admitted to the CCU, patients admitted to the INTCU or Ward after being monitored at least 24 h had non-ST elevation and non-Q wave AMI more frequently, but a less favorable risk profile for long-term mortality. The different types of AMI were managed similarly and had a similar 12-month prognosis. Intermediate care units may be useful for palliating the lack of CCU beds and care for some patients with AMI.     

Evaluation of treatment of acute myocardial infarction before admission to a coronary care unit

A fact-finding survey was conducted to ascertain the treatment of 298 patients with acute myocardial infarction (AMI) who were referred to our coronary care unit (CCU) from other medical facilities between May 1978 and December 1987. The controls consisted of 169 patients with AMI who were admitted directly to our CCU during the same period. The mean time from onset of AMI to admission to our CCU was 21.7 +/- 67.9 hours (mean +/- SD) for patients from other medical facilities, and it took longer than that of the controls (11.7 +/- 34.9 hours). However, the mortality was 19.8%, being lower than that of the controls (26.0%). By the Killip's classification, there was no significant differences between both patient groups who belonged to Killip groups I, II and IV, but the mortality of cases in Killip group III was 3.7%, which was lower than that of the controls (7.15%). Among the 298 cases, 169 (56.7%) had received some kind of emergency treatment, and their mortality was 29.9%. However, the mortality of the remaining 129 cases (43.3%) who had received no emergency treatment was only 17.1%. The reason for this contradictory result is attributed to the fact that the former group included relatively severe cases. The number of patients receiving emergency treatment has gradually increased recently; however, the overall results achieved were not satisfactory even with appropriate therapy. Since April 1984, conferences with local practitioners have been held concerning emergency treatment for ischemic heart disease. This resulted in better understanding of CCU among the practitioners, less time delay until admission, and increased frequency and higher quality of emergency treatment. However, the mortality in the CCU did not decline, probably because of the relatively high rate of severe cases. To reduce mortality of AMI, a communication network should be established between practitioners and the CCU.     

Intracoronary streptokinase therapy in the coronary care unit for acute myocardial infarction

Intracoronary streptokinase was offered and preliminary coronary angiography performed in 14 patients who were seen with the clinical diagnosis of acute myocardial infarction within 4 h of onset of symptoms. The procedure was performed in the Coronary Care Unit (CCU) of St. Peter's Medical Center with the use of a portable C-arm fluoroscope. Angiography was recorded on video tape. Service was provided by an "on-call" team consisting of two physicians, a CCU nurse, and a radiology technician, on a 24-h service basis. Adequate visualization of coronary anatomy was obtained in all patients. Patency of occluded vessels was achieved in 10 of 11 patients who received intracoronary streptokinase. The initial streptokinase bolus was administered at a mean interval of 4.1 h from onset of symptoms. It is concluded that speedy and effective coronary thrombolytic therapy can be provided in the CCU on a 24-h service basis by an on-call team. The use of CCU for this purpose will make this therapy widely available across the country, without the need for Cardiac Catheterization Laboratory.     

Impact of physician experience on triage of emergency room patients with acute chest pain at three teaching hospitals

PURPOSE: To determine whether the experience of the physician (as measured by postgraduate training level or time during the academic year) who performs the initial evaluation affects the triage of patients with acute chest pain. PATIENTS AND METHODS: Prospective data on the presenting clinical features, initial triage, final diagnosis, and complications were collected for 7,857 patients who presented to the emergency rooms of three teaching hospitals, including 1,118 (14%) with acute myocardial infarction (AMI), 2,477 (32%) with acute ischemic heart disease (AIHD) (i.e., AMI or unstable angina), and 335 (4%) with major complications. The experience of the evaluating physicians, who were in their first three postgraduate years in 93% of cases, was measured in three ways: (1) postgraduate training level, (2) month during the academic year, and (3) number of patients with acute chest pain previously evaluated. Multivariate logistic regression analyses that adjusted for hospital site and 20 clinical variables estimated the odds ratios for admission to the coronary care unit (CCU) and hospital associated with each incremental increase in physician experience. RESULTS: With more experience (as measured by postgraduate training level or time during the academic year), the sensitivity of physicians for admitting patients with AMI, AIHD, or major complications to the hospital increased. For example, each incremental increase in postgraduate training level carried a 1.4 increase in the adjusted odds ratio for admission of a patient with AIHD to the hospital (p less than 0.05), corresponding to an increase in the probability of admission from 93% to 97%. However, increasing physician experience was also associated with an elevated false-positive rate in admitting patients without these diagnoses to the CCU and hospital. Thus, each incremental increase in postgraduate training level carried a 1.2 increase in the adjusted odds ratio for admission of a patient without AIHD to the CCU and hospital (p less than 0.005), corresponding to an increase in the probability of admission from 34% to 47%. By receiver operating characteristic curve (ROC) regression analyses, these changes in triage patterns were consistent with movement along a single ROC curve, rather than a shift to a new or better ROC curve. CONCLUSIONS: As the experience of the physician who performed the initial evaluation increased, there was a lower threshold for admitting all patients with and without AMI, AIHD, or major complications to the CCU and hospital without a detectable improvement in diagnostic accuracy.     

Chest pain in the emergency room. Importance of a systematic approach

OBJECTIVE: To evaluate the efficiency of a systematic diagnostic approach in patients with chest pain in the emergency room in relation to the diagnosis of acute coronary syndrome (ACS) and the rate of hospitalization in high-cost units. METHODS: One thousand and three consecutive patients with chest pain were screened according to a pre-established process of diagnostic investigation based on the pre-test probability of ACS determinate by chest pain type and ECG changes. RESULTS: Of the 1003 patients, 224 were immediately discharged home because of no suspicion of ACS (route 5) and 119 were immediately transferred to the coronary care united because of ST elevation or left bundle-branch block (LBBB) (route 1) (74% of these had a final diagnosis of acute myocardial infarction [AMI]). Of the 660 patients that remained in the emergency room under observation, 77 (12%) had AMI without ST segment elevation and 202 (31%) had unstable angina (UA). In route 2 (high probability of ACS) 17% of patients had AMI and 43% had UA, whereas in route 3 (low probability) 2% had AMI and 7 % had UA. The admission ECG has been confirmed as a poor sensitivity test for the diagnosis of AMI ( 49%), with a positive predictive value considered only satisfactory (79%). CONCLUSION: A systematic diagnostic strategy, as used in this study, is essential in managing patients with chest pain in the emergency room in order to obtain high diagnostic accuracy, lower cost, and optimization of the use of coronary care unit beds.     

The Prognosis for Patients Admitted to a Coronary Care Unit due to Suspected Acute Myocardial Infarction with and without Confirmed Diagnosis

ABSTRACT. In a retrospective study the incidence of AMI and death after discharge from CCU have been recorded in 67 patients with and 93 without a diagnosis of AMI confirmed in the CCU. No statistically significant differences were found between the two groups in mortality rate during the first 3 years, 18.3% (non-AMI) and 22.4% (AMI), or in cardiac events, sudden death and AMI, 19.3% (non-AMI) and 24.9% (AMI), during the first 2 years after discharge. Non-AMI patients with either previous AMI, angina pectoris or ST-T abnormalities in the ECG accounted for the major part of cardiac events in this group. The mortality rates in the two groups, compared to a normal population matched for sex and age, were in the AMI group in the 1st year 13.4 and 2.6% (p<0.01), in the 2nd year 3.4 and 2.8% (p>0.05), in the 3rd year 7.1 and 2.9% (p>0.05) and in the non-AMI group in the 1st year 11.8 and 1.8% (p<0.01), in the 2nd year 3.7 and 2.0% (p>0.05), in the 3rd year 3.8 and 2.1% (p>0.05). It is concluded that the prognosis after discharge from the CCU is as unfavourable for patients without as for patients with AMI. The mortality is highest during the first 6–12 months after discharge.     

肌钙蛋白I在急诊心房颤动和心房扑动患者检测情况分析

目的:回顾性分析心肌标志物肌钙蛋白I(Troponin I,TnI)在急诊科心房颤动和心房扑动(房颤/房扑)患者的检测情况。方法:收集2010年6月至2011年6月,就诊于北京安贞医院急诊科2 190例房颤/房扑患者病例,随机抽取了500例患者的资料进行回顾性分析,分析内容包括肌钙蛋白I检测次数,TnI阳性率和确诊为急性冠状动脉综合征(ACS)的概率。结果:患者至少有1次TnI检测的为86.8%(434/500),其中TnI阳性率为15.7%,诊断为ACS者的概率为5.1%。至少2次检测的患者为41.8%(209/500),其中TnI阳性率为26.8%(56/209),诊断为ACS的占9.6%。结论:在急诊科,房颤/房扑患者有很高的TnI检测率,而急诊患者确诊为ACS仅约5%,提示急诊内科医师需综合评估房颤/房扑患者临床状况后再进行TnI检测,避免临床资源不必要的浪费。     

Usefulness of two-dimensional echocardiography for immediate detection of myocardial ischemia in the emergency room

Inappropriate discharge from the emergency room of patients with acute chest pain may have serious consequences. Regional asynergy is one of the first signs of myocardial ischemia and can be detected with 2-dimensional echocardiography (2-DE). This study determines the value of 2-DE in the emergency room for immediate detection of myocardial ischemia causing acute chest pain at the time the electrocardiogram was nondiagnostic. Forty-three patients (32 men and 11 women) with a normal or nondiagnostic electrocardiogram during acute chest pain were studied with 2-DE. Only patients without a previous myocardial infarction and without known coronary artery disease (CAD) were studied. The entire left ventricular wall was examined for presence of regional asynergy. Coronary angiography was performed within 3 weeks. Cardiac enzyme levels were measured serially to establish or rule out an acute myocardial infarction. Sensitivity of 2-DE for detection of myocardial ischemia was 88% (22 of 25), specificity 78% (14 of 18), negative predictive accuracy 82% (14 of 17) and positive predictive accuracy 85% (22 of 26). Sensitivity of 2-DE for detection of acute myocardial infarction was 92% (12 of 13), specificity 53% (16 of 30) and negative predictive accuracy 94% (16 of 17). Thus, 2-DE during pain and a nondiagnostic electrocardiogram can readily identify patients with CAD in the emergency room, and it can accurately rule out an acute myocardial infarction.     

Analysis of the treatment of acute myocardial infarction using ambulance records in Japanese cities

By means of ambulance records, the current state of medical services for the treatment of acute myocardial infarction (AMI) was investigated in Chiba City and Ichihara City, Japan. From all patients transported by ambulance personnel in 1992 (n=31,191), 388 patients who were admitted within 2 weeks after the onset were studied. Types of admitting institution, diagnoses, medical treatments and prognoses were investigated. According to medical records, 168 patients fulfilled the criteria of definite AMI and were admitted alive. Percutaneous transluminal coronary angioplasty (PTCA) and recanalization (PTCR) were performed on 54 and 6 patients, respectively. The hospital case-fatality rates were lower in the patients who underwent emergency PTCA or PTCR than in the others. Emergency PTCA or PTCR, and admission to coronary care units (CCU) or institutions equipped with coronary angiography, decreased the fatality risk, even after considering age, sex, and disease severity. These results show the importance of the selection of institutions for AMI patients. Because 40% of definite AMI patients were sent to institutions without CCU, it is essential that enough CCU are available through an improvement in cooperation between the various types of institutions, and in the proper transfer of AMI patients to CCU     

Brachial approach to emergency cardiac catheterization during thrombolytic therapy for acute Myocardial Infarction

The use of the brachial approach to acute coronary intervention has not been previously studied. In the course of the Thrombolysis and Angioplasty in Myocardial Infarction (TAMI) trials, we used the transbrachial approach to cardiac catheterization with or without angioplasty in 202 of 704(28.6%) patients. The baseline characteristics of age, sex, risk factors, medical history, time from symptom onset to therapy, and left ventricular function were similar for the 2 different approaches. Time from therapy to coronary angiography was not delayed by the brachial approach compared with the femoral approach: 97.1±26 min vs. 99.9±133.8 min, respectively. Chemical patency was established in 78 vs. 73% of patients and technical success with acute PTCA with the brachial approach was 89% vs. 78% with the femoral approach. Clinical outcomes were quite similar with respect to death(6 vs. 6%), reocclusion (10 vs. 14%), and emergency coronary bypass surgery (5 vs. 6%). Baseline hematocrit was 43.9±4.4 and 43.5±4.8, respectively with a nadir of 32.9±5.6 vs. 33.0±5.4. The need for vascular repair occurred in 1% vs. 3% of patients and retroperitoneal hemorrhage was documented in 1% vs. 1% of patients. This study indicates that in thehands of experienced operators the transbrachial approach to acute coronary intervention in theacute phase of treatment with thrombolytic therapy can be used with equal risks and efficacy asthe femoral approach.     

Current status of prehospital care of patients with acute myocardial infarction in Tokyo: analysis of 3-year experience with coronary care unit network

To clarify the current status of prehospital care of patients with acute myocardial infarction (AMI) in the Tokyo metropolitan area, the availability of the coronary care unit (CCU) network during the past 3 years (January 1982 through December 1984) was analyzed, examining: final diagnosis, circumstances at the onset of AMI, course of transportation to CCU, time elapsed before admission, severity of AMI, and prognosis of patients. Of 6,939 patients admitted to CCU by means of the CCU network, 2,408 patients (34.7%) had AMI. The patient's decision time was, on the average, 12 hr 3 min, longer when the course of transportation to CCU was more complicated. The fatality for AMI was 17.2%. Causes of death were pump failure in 52.8%, arrhythmias in 62.8% and mechanical failure such as cardiac rupture in 8.5%. Patients with complicated AMI were admitted earlier and had a higher fatality than those without complications. Thus, community oriented programs are required to more fully inform the population at risk of AMI to shorten the patient's decision time, and more effective means to treat patients with pump failure and to prevent the development of pump failure need to be established.     

Low-risk patients with chest pain and without evidence of myocardial infarction may be safely discharged from emergency department.

AIMS: This study is an audit of the risk stratification of patients admitted to a university hospital emergency department with a suspected acute coronary syndrome (ACS). The main aim of the study was to investigate the prognosis of those patients who were discharged to home from the emergency room (ER) or adjacent chest pain observation unit (CPU). METHODS AND RESULTS: Three thousand one hundred and seven consecutive patients admitted to the ER with a suspected ACS were retrospectively identified. Seven hundred and sixty-four (25%) patients were discharged from the ER and 417 (13%) from the CPU after observation and ruling out myocardial infarction (MI) and high-risk ACS. One thousand seven hundred and two patients were hospitalized. Follow-up end-points were cardiovascular mortality, hospitalization for ACS and incidence of any cardiovascular disease event during 6 months. During 4 weeks after the discharge from the ER and CPU cardiovascular mortality was 0.1% and 0.5% and during 6 months 0.8% and 1.7%, respectively. Within 6 months 4.2% and 8.4% of the patients were hospitalized for ACS and 9.3% and 11.5% had a cardiovascular disease event. CONCLUSIONS: Patients admitted with chest pain may be safely discharged from the emergency department, if there is no evidence of MI or high-risk ACS. However, further examination and appropriate treatment must be arranged.