Chest pain unit: one-year follow-up

INTRODUCTION AND OBJECTIVES: In Spain there is little information available about chest pain units for the treatment of patients of low-to-medium risk with suspected acute coronary syndrome. PATIENTS AND METHOD: A prospective study was performed among emergency room patients who complained about acute chest pain and were suspected of suffering an acute coronary syndrome with a normal or unspecific initial evaluation. They underwent an early submaximum stress test to decide on possible hospitalization. The follow-up time was 1 year. RESULTS: Of 472 emergency room patients with suspected acute coronary syndrome, 179 performed the stress-test during the first hours of the triggering chest pain episode. None met the high-risk criteria for unstable angina. In 78.8% of the cases, the test results were negative and the patients were discharged. The results were positive in 15.1% and inconclusive in 6.1%; there were no complications during the procedure. Patients with a negative stress test had a more favorable outcome than the rest, with fewer following visits to the emergency room (11% vs 22%, p<0.001). One patient with a negative stress test died of a non-cardiovascular complication. None of the patients suffered acute myocardial infarction during follow-up and 89% of the patients with negative stress test had a favorable outcome (in terms of visits to the emergency room, unstable angina, acute myocardial infarction, or cardiovascular death). CONCLUSIONS: Chest pain units for the care of low-to-medium risk patients with acute chest pain allow a fast and safe hospital release with a favorable mid-term outcome.     

Human heart-type fatty acid-binding protein as an early diagnostic and prognostic marker in acute coronary syndrome

Although heart-type fatty acid-binding protein (H-FABP) can be a marker of sarcolemmal injury due to acute myocardial ischemia, the diagnostic or prognostic value is not established in patients with acute chest pain. This multicenter prospective study aimed to determine the diagnostic and prognostic values of H-FABP in 133 patients presenting to an emergency room with suspected acute coronary syndrome (ACS) by comparing with those of conventional biomarkers. H-FABP and myoglobin had greater positive results than did creatine kinase-MB or troponin T. Receiver operating characteristics analysis revealed that H-FABP was the most reliable for detection of ACS and that H-FABP had the greatest sensitivities for identification of patients requiring emergency hospitalization, coronary angiography, and interventional therapy within 7 days among the biomarkers. Thus, H-FABP can be an early diagnostic and prognostic biochemical marker, particularly within the first 6 h from the onset of chest symptoms, in patients with chest pain at an emergency department.     

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 diagnosis of myocardial infarction by computer-derived protocol in a municipal hospital

The evaluation of an emergency room patient with acute chest pain is often difficult. Recently, computers have been employed to develop protocols for identifying which patients are likely to have acute myocardial infarctions and to benefit, therefore, from admission to a relatively scarce coronary care unit bed. We have tested the latest computer-derived instrument in a municipal hospital and found it to be less reliable than the clinical judgement of physicians.     

Early positive biomarker in relation to myocardial necrosis and impaired fatty acid metabolism in patients presenting with acute chest pain at an emergency room.

BACKGROUND: Measurement of circulating biomarkers has enabled early diagnosis and risk assessment of acute coronary syndrome. This study sought diagnostic values of the first single-point data of biomarkers obtained soon after patient arrival by comparing with scintigraphically quantified myocardial injury in patients presenting with acute chest pain at an emergency room. METHODS AND RESULTS: Serial blood samples were taken soon after arrival in an emergency department in 74 patients with suspected acute coronary syndrome to quantify blood levels of troponin-T (TnT), heart-type fatty acid-binding protein (H-FABP), myocardial-bound creatine kinase (CK-MB), and myoglobin. Myocardial perfusion and metabolic defects were scintigraphically quantified. The first single-point data had high positive predictive values for detecting the defects (80-100%) but low negative predictive values (15-41%). CK-MB and TnT had higher specificities (73-100%) but significantly lower positive rates (22-27%) than the others (61-68%), resulting in greater sensitivities of H-FABP and myoglobin (75-80%) than those of CK-MB and TnT (29-35%). Among biomarkers, TnT peak concentrations most closely correlated with scintigraphic abnormalities. CONCLUSION: H-FABP can contribute to early detection of myocardial injury and TnT is most likely to correlate with injured myocardial mass. The differential features of biomarkers are complementary in patients with acute chest pain presenting at an emergency room.     

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.     

Der extrakardiale Thoraxschmerz

In patients with an acute chest pain syndrome the primary requirement is to diagnose or exclude acute myocardial ischemia or myocardial infarction. However, only 30% of patients admitted and evaluated for chest pain ultimately reveal the diagnosis of acute coronary syndrome.Traditionally, the initial evaluation of patients presenting with chest discomfort or pain to an emergency department or any general practice involves the triad of history, physical examination, and ECG and chest film evaluation. With the diagnostic routine of bedside enzymatic tests for cardiac biomarkers, it has become easier to identify acute coronary syndromes, but at the same time more compelling to pinpoint other differential diagnoses, once coronary syndromes are excluded.When a cardiac origin of any non-suggestive chest pain syndrome has been excluded, a broad spectrum of other causes for noncardiac chest pain needs to be evaluated. Potential underlying disorders are listed in this overview and grouped according to pathoanatomic origin into aortic, respiratory, and gastroesophageal disorders, musculoskeletal pathology, and somatization disorders. This article reviews both symptoms and diagnostic pathways in patients with noncardiac chest pain, and eventually offers a rational strategy for an efficacious workup of a wide spectrum of important differential diagnoses.     

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.     

Biomarkers of myocardial ischemia in the emergency room: cardiospecific troponin and beyond

A timely and efficient diagnosis is critical in patients with chest pain, to optimize the efficacy of myocardial revascularization in those with an acute coronary syndrome, and offset the increasing overcrowding in the emergency room by early discharge of subjects without myocardial ischemia. Although cardiospecific troponins remain the biochemical gold standards for diagnosing an acute coronary syndrome, several additional biomarkers have been proposed. As a general rule, there are important issues that should be addressed when combining an innovative diagnostic test with troponin, including a benchmark evaluation of diagnostic performance, the impact on throughput and turnaround time, along with the analytical features of the assay and the cost to benefit ratio of a multi-marker approach. Despite a considerable amount of data has been published, there is insufficient analytical and clinical evidence to support the use of most of these novel biomarkers as surrogates or in combination with troponin for diagnosing ischemic heart disease, especially when the latter is assessed with the novel highly-sensitive immunoassays.     

Prospective evaluation of an EDB-based diagnostic program to be used in patients admitted to hospital with acute chest pain

A recently designed computer based decision support system (DSP),almost exclusively based on case history data, was developedto facilitate immediate differentiation between patients withand without urgent need for coronary care unit (CCU) transferralfrom the emergency room, and additionally to distinguish betweenpatients with and without acute myocardial infarction (MI). One-year's prospective testing in a consecutive series of 1252patients with acute chest pain revealed that the DSP, used inaddition to ECG and clinical examination, demonstrated a sensitivityof 96% in the detection of patients in need of CCU observation(MI-sensitivity of 98%), and a specificity of 56% in excludingpatients who were not in need of CCU observation. The proportionof referrals to the CCU judged to be unnecessary was only 17%of the total number of patients seen in the emergency room.     

Chest pain emergency units.

Each year in the United States, more than 2 million patients are hospitalized with chest pain suggestive of myocardial ischemia, with fewer than 20% of these patients having an acute coronary event. Chest pain emergency units have been created to facilitate urgent therapy for patients with a serious cardiovascular event and to triage lower risk patients to less intensive, more cost-effective inpatient care or discharge to home. The clinical history, physical examination, and initial electrocardiogram are key to initial stratification of patients for further management, but additional methods are necessary to clearly distinguish patients with inconclusive findings at presentation as high- and low-risk. Innovative electrocardiographic methods have increased sensitivity for detecting myocardial ischemia. Accelerated diagnostic protocols with new cardiac serum markers can detect myocardial ischemia or infarction with increasing accuracy. Early echocardiographic, scintigraphic, and treadmill stress protocols can further evaluate patients who have nondiagnostic electrocardiograms and negative serum markers. This review presents the current status of chest pain emergency units and the evolving management strategies they encompass.     

Early diagnosis of acute myocardial infarction by a newly developed rapid immunoturbidimetric assay for myoglobin.

OBJECTIVE--To evaluate a rapid immunoturbidimetric assay for myoglobin and to investigate its clinical usefulness in the early detection of acute myocardial infarction. DESIGN--Prospective study. Immunoturbidimetrically determined myoglobin concentrations were compared with radioimmunoassay results obtained with the same blood samples. The diagnostic performance of myoglobin determination was compared with creatine kinase and creatine kinase MB activity (current standard of routine diagnosis). SETTINGS--Part 1: coronary care unit. Part 2: emergency room in a university hospital. PATIENTS--Part 1:30 patients with acute myocardial infarction admitted not later than four hours (median two hours) after the onset of symptoms. Part 2: 126 patients admitted to the emergency room with chest pain not caused by trauma (51 cases of acute myocardial infarction, 51 cases of angina pectoris, and 24 cases of chest pain not related to coronary artery disease). INTERVENTIONS--Part 1: routine treatment including intravenous thrombolytic treatment (28 patients). Part 2: routine emergency treatment without thrombolytic treatment. MAIN OUTCOME MEASURES--The analytical quality of the immunoturbidimetric myoglobin assay and a comparison between the myoglobin assay and creatine kinase and creatine kinase MB for diagnostic sensitivity and performance. RESULTS--The immunoturbidimetric myoglobin assay was fast and convenient and gave myoglobin determinations of high analytical quality. The concentration of myoglobin increased, peaked, and returned to the reference range significantly earlier than creatine kinase (p < or = 0.0001) and creatine kinase MB (p < or = 0.0002). Before thrombolytic therapy was started the diagnostic sensitivity of myoglobin was significantly higher than that of creatine kinase MB activity 0-6 h after the onset of chest pain and significantly higher (0.82 v 0.29) than creatine kinase 2-4 h after the onset of chest pain. In almost all patients (92%) plasma myoglobin concentrations were increased 4-6 h after the onset of chest pain. CONCLUSION--Myoglobin was more sensitive in detecting early myocardial infarction than creatine kinase and creatine kinase MB activity. Immunoturbidimetric myoglobin measurements could be useful in the early evaluation of patients with suspected myocardial infarction because this assay takes less than two minutes.     

Beat-to-beat morphologic variability of the electrocardiogram for the evaluation of chest pain in the emergency room.

The value of electrocardiographic, morphologic variability in the early diagnosis of acute myocardial infarction (AMI) and myocardial ischemia was evaluated in 49 nonselected patients presenting to the emergency room with chest pain. High-resolution electrocardiography was used to determine the morphologic variability of consecutive electrocardiographic complexes, and the ratio of the variance of the QRS onset to that of the entire electrocardiogram was calculated. A final diagnosis of AMI was confirmed in 8 patients, acute coronary insufficiency in 8, angina pectoris in 19, and a noncardiac origin for chest pain in 14. Patients with AMI had a significantly higher beat-to-beat electrocardiographic morphologic variability of the QRS onset (1.4 +/- 0.2) than did those with acute coronary insufficiency (1.1 +/- 0.2), angina pectoris (0.9 +/- 0.1) or noncardiac chest pain (0.8 +/- 0.1) (p < 0.05). The sensitivity of the clinical presentation, typical electrocardiographic changes and creatine phosphokinase levels for the diagnosis of an acute ischemic event on admission to the emergency room was 62, 25 and 37.5%, respectively. Relative variance of the QRS onset of > 0.86 had a sensitivity of 75% and a specificity of 61% for diagnosing an acute ischemic event. Logistic regression of these variables showed that the QRS onset relative variability is an independent predictor for an acute ischemic event. It is concluded that an increased beat-to-beat electrocardiographic variability in patients with AMI is present on admission to the emergency room and may assist in establishing the diagnosis in this setting.     

Technetium-99m sestamibi myocardial perfusion imaging in the emergency room evaluation of chest pain

Objectives. The purpose of this investigation was to evaluate the practicality and short-term predictive value of acute myocardial perfusion imaging with technetium-99m sestamibi in emergency room patients with typical angina and a normal or nondiagnostic electrocardiogram (ECG).Background. Accuracy of emergency room chest pain assessment may be improved when clinical and ECG variables are used in conjunction with acute thallium-201 myocardial perfusion imaging. Technetium-99m sestamibi is a new radioisotope that is taken up by the myocardium in proportion to blood flow, but unlike thallium-201, it redistributes minimally after Injection. Technetium-99m sestamibi can thus be injected during chest pain, and images acquired 1 to 2 h later (when patients have been clinically stabilized) will confirm whether abnormalities of perfusion were present at the time of injection.Methods. One hundred two emergency room patients with typical angina (on the basis of a standardized angina questionnaire) and a normal or nondiagnostic ECG had a technetium-99m sestamibi injection during symptoms and were followed up for occurrence of adverse cardiac events (cardiac death, nonfatal myocardial infarction, coronary angioplasty, coronary surgery or coronary thrombolysis).Results. Univariate predictors of cardiac events included the presence of three or more coronary risk factors (p = 0.009, risk ratio 3.3) and an abnormal or equivocal acute technetium-99m sestamibi scan (p = 0.0001, risk ratio 13.9). Multivariate regression analysis identified an abnormal perfusion image as the only independent predictor of adverse cardiac events (p = 0.009). Of 70 patients with a normal perfusion scan, only 1 had a cardiac event compared with 15 patients with equivocal scans or 17 patients with abnormal scans, with a cardiac event rate of 13% and 71%, respectively (p = 0.0004).Conclusions. Initial myocardial perfusion imaging with technetium-99m sestamibi when applied in emergency room patients with typical angina and a normal or nondiagnostic ECG appears to be highly accurate to distinguishing between low and high risk subjects.     

Inpatient telemetry does not need to be used in the management of older patients hospitalized with chest pain at low risk for in-hospital coronary events and mortality

BACKGROUND: Little is known about patients admitted with chest pain to inpatient telemetry units directly from an emergency department. METHODS: We analyzed data from 105 consecutive patients who presented with chest pain to an emergency department and who were hospitalized in an inpatient telemetry unit but who were at low risk for a coronary event. RESULTS: Telemetry yielded no information which was used to manage any patient. None of the 105 patients (0%) developed a myocardial infarction or died during hospitalization. At 4.8-year follow-up, 8 of 105 patients (8%) died. Significant risk factors for long-term mortality were age (p < .001), prior coronary artery disease (p < .05), and diabetes (p < .02). CONCLUSIONS: Inpatient telemetry was of no value in predicting short-term coronary events or mortality or long-term mortality in low-risk patients hospitalized with chest pain.     

La prise en charge rapide des douleurs thoraciques aux urgences

Acute chest pain is a common reason of consultation in the emergency department. The difficulty lies in discriminating patients with acute coronary syndrome or other life-threatening conditions from those non-cardiovascular, non-life-threatening chest pain. Only 15 to 25 % of patients with acute chest pain actually have acute coronary syndrome. Algorithms using high sensitivity troponin at admission and a second assessment 1 or 3 hours later are validated to “rule in” or “rule out” the diagnosis of non ST-elevation myocardial infarction. This may reduce the delay for the diagnosis translating into shorter stay in the emergency department. Those algorithms must be interpreted in the context of clinical and ECG criteria.     

Management Strategies for Patients with Low-Risk Chest Pain in the Emergency Department

There is abundant evidence to guide the management of chest pain patients with a confirmed or reasonably suspected diagnosis of acute coronary syndrome (ACS). But when it comes to the low-risk chest pain patient in the emergency department, there is limited evidence to support one approach over another. As a result, the evaluation of low-risk chest pain represents a distinct challenge for the emergency physician. Missing a diagnosis of ACS is certainly undesirable. However, the overuse of technology can result in misleading test results in populations with a low incidence of coronary disease. In this article, we dispel several myths surrounding low-risk chest pain and put forward a number of common-sense recommendations. We endorse taking a focused but thorough chest pain history; encourage the use of serial electrocardiogram, particularly for patients with ongoing or changing symptoms; comment on the interpretation of cardiac biomarkers in the era of highly sensitive troponin assays, drawing a distinction between myocardial injury and myocardial infarction; discuss the role of coronary computed tomography angiography as a test for coronary artery disease, rather than for ACS; and caution against the reflexive use of provocative testing in low-risk chest pain patients.     

Candidates for thrombolysis among emergency room patients with acute chest pain. Potential true- and false-positive rates

STUDY OBJECTIVE: To assess the potential clinical impact of thrombolytic therapy for acute myocardial infarction by determining true-positive and false-positive rates of criteria for eligibility among emergency room patients with acute chest pain. DESIGN: Prospective multicenter cohort study. SETTING: Emergency rooms of three university and four community hospitals. PATIENTS: Emergency room patients (7734) with acute chest pain. MEASUREMENTS AND MAIN RESULTS: Only 261 (23%) of 1118 patients with acute myocardial infarctions were 75 years of age or younger, presented within 4 hours of the onset of pain, and had emergency room electrocardiograms showing probable acute myocardial infarction: 60 (0.9%) of the 6616 patients without infarction also met these criteria (positive predictive value, 261/321 = 81%; CI, 77% to 86%). The positive predictive value could increase to about 88% (CI, 82% to 93%) if eligibility were based on the official hospital electrocardiogram reading. CONCLUSIONS: Because experience from published studies suggests that about one third of patients who meet these three eligibility criteria have other contraindications to thrombolysis, we estimate that about 15% of patients with acute myocardial infarction would meet the criteria for eligibility for thrombolysis that have been used in clinical trials at the time of emergency room presentation. Further, for every eight patients with true-positive results who are treated, one to two patients with false-positive results may also be treated if decisions are based on the interpretation of a single electrocardiogram.     

Chest pain centers: diagnosis of acute coronary syndromes

Chest pain centers in the emergency department have generally been accepted as a safe, cost-effective, and rapid approach to the evaluation, triage, and management of patients with potential acute coronary syndromes. These centers were initially designed to enhance patient care by decreasing time to treatment for acute myocardial infarction (AMI) and rapidly identifying patients with unstable angina. They also included community outreach and educational objectives designed to reduce time from the onset of chest pain to ED presentation. In the past decade, health care financial constraints have created additional impetus to the development of chest pain centers. Cost reduction efforts have occurred to reduce hospitalizations, lengths of stay, and unnecessary treatments and procedures. Practitioners and administrators try to balance these goals with the imperative to provide high-quality patient care. Protocol-driven approaches have been developed for specific disease processes in emergency settings. The chest pain center concept is such an approach for patients with chest pain. Chest pain is the second most common ED presenting complaint and is a symptom related to the leading cause of death in the United States, coronary artery disease (CAD). One third of ED patients with chest pain will eventually have a diagnosis of acute coronary syndrome. Many patients with acute coronary syndromes have atypical presentations that are not diagnosed in the ED with the traditional diagnostic evaluation of a history, physical examination, and 12-lead ECG. If they are not admitted to the hospital for further evaluation, the diagnosis may be missed. The 2% to 5% of AMI patients who are inadvertently released home often have poor outcomes and result in a leading cause of malpractice suits in emergency medicine. More than one half of ED patients with chest pain have clinical findings after their initial evaluation consistent with acute coronary syndromes and are admitted to the hospital. Approximately one half of these patients, after evaluation in the hospital, are found not to have acute coronary syndromes. The cost for these negative inpatient cardiac evaluations has been estimated to be $6 billion in the United States each year. Today, chest pain centers serve as an integral component of many EDs. Their success and safety is the result of a focused, protocol-driven approach directed at the acute coronary syndrome continuum from unstable angina to transmural Q-wave myocardial infarction. New therapies for acute coronary syndromes make ED triage and risk stratification increasingly important. Although different chest pain center protocols have proved effective, all address the diagnosis and rapid treatment of acute myocardial necrosis, rest ischemia, and exercise-induced ischemia. Identifying patients with coronary artery disease in one of these stages in the spectrum of myocardial ischemia is the foundation for a successful chest pain center in the ED.     

Positive troponin T in a chagasic patient with sustained ventricular tachycardia and no obstructive lesions on cine coronary angiography

The assessment and stratification of patients with chest pain in the emergency unit may indicate the appropriate therapy for each patient based on the probability of the presence of acute coronary artery disease and on the risk of its major cardiac events. That assessment is based on the triplet: clinical setting, electrocardiographic findings, and markers of myocardial lesion. We report the case of a 58-year-old male chagasic patient admitted to the emergency unit due to chest pain and palpitations, with an electrocardiogram showing sustained ventricular tachycardia and positive troponin measurement (0.99 ng/mL). The patient underwent cine coronary angiography, which evidenced no obstructive coronary artery disease.