Non-diagnostic ECG Research Articles

741 Clinical characteristics and short-term outcome of patients diagnosed with Brugada syndrome and a basal non-diagnostic ECG

741 Clinical characteristics and short-term outcome of patients diagnosed with Brugada syndrome and a basal non-diagnostic ECG

Efficacy of Multislice Computed Tomography for the Detection of Acute Coronary Syndrome in the Emergency Department

The diagnosis of acute coronary syndrome (ACS), especially non-ST-elevation myocardial infarction and unstable angina in the emergency department (ED) still remains a challenge. Multislice computed tomography (MSCT) allows assessment of not only coronary artery stenoses and occlusions, but also assessment of coronary artery plaques and myocardial perfusion status. MSCT was performed in 31 patients who were admitted to the ED because of chest pain persisting at least 30 min and non-diagnostic ECG changes and normal serum enzyme concentrations. Using MSCT, ACS was defined by coronary artery stenosis > or = 75% accompanied by computed tomography (CT)-low-density plaques, and/or by the presence of myocardial perfusion defects. ACS was confirmed by coronary stenosis > or = 75% by coronary angiography and/or subsequent elevation of troponin I concentration. In total, 22 patients were diagnosed as having ACS. MSCT detected stenoses with CT-low-density plaques in 21 and non-transmural myocardial perfusion defect in 3 patients. There was 1 false-positive and 1 false-negative result. The sensitivity and specificity of MSCT to identify ACS was 95.5% and 88.9%, respectively. MSCT provides diagnostic operating characteristics suitable for triage of patients with ACS in the ED.

A Diagnostic Value of Ischemia Modified Albumin in Patients with Suspected Acute Coronary Syndrome with Normal EKG and Cardiac Markers

Background and Objectives：In the early phase of acute chest pain, the diagnosis of acute coronary syndrome (ACS) is often difficult to achieve in an emergency department (ED) due to the non-diagnostic ECG and cardiac markers. Ischemia modified albumin (IMA) has recently been shown to be a sensitive early biochemical marker of ischemia. The aim of this study was to evaluate the diagnostic value of IMA for the patients with suspected ACS and who have normal ECG/cardiac markers. Subjects and Methods：We enrolled 142 consecutive patients who presented to the ED due to suspected ACS, and they had a normal EKG and troponin-I/CK-MB within 5 hours after the onset of their chest pain. The diagnosis of ACS was based upon the clinical findings, the results of serial ECG/troponin and the coronary angiography. The ideal cutoff value of IMA for ACS was calculated by the receiver operator characteristic (ROC) curve analysis. Results：The ACS was diagnosed in 80/142 (56%). The ROC curve area for the IMA test was 0.77 (CI; 0.70-0.85, p<0.01). At a cutoff value of 98.5 U/mL, the sensitivity, specificity and negative predictive values for ACS were 73%, 75% and 75%, respectively. At a cutoff value of 85 U/mL, the sensitivity and specificity and negative predictive values for ACS were 92%, 35% and 95%, respectively. Conclusion：IMA might be a useful diagnostic marker of ACS for those patients with normal ECG/cardiac markers and who present within 5 hours after the onset of chest pain. (Korean Circulation J 2005;35:928-933)

Principal Component Analysis of the T Wave in Patients with Chest Pain and Conduction Disturbances

There is a need for markers reflecting the increased risk in patients with conduction disturbances. Conduction disturbances presumably cause inhomogeneous repolarization that may create an arrhythmogenic substrate. In patients with normal conduction, parameters derived from principal components analysis (PCA) of the T wave contain prognostic information. The nondipolar PCA components are assumed to reflect repolarization inhomogeneity. This study examined the PCA parameters in relation to conduction disturbances. PCA was performed on continuously recorded 12-lead ECGs in 800 patients with chest pain and nondiagnostic ECG on admission. The patients with conduction disturbance on admission were classified into separate groups and related to comparison groups without conduction disturbance recruited from the same series. For each patient, the dipolar and nondipolar components were quantified by medians of the ratio of the two largest eigenvalues (S2/S1 Median), the residue that summarizes the eigenvalues S4-S8 (TWRabsMedian) and the ratio of this residue to the total power of the T wave (TWRrelMedian). The parameters were assessed with respect to common clinical and ECG parameters, discharge diagnosis, and total mortality during a 35-month follow-up. TWRabsMedian increased with increasing conduction disturbance. In 135 patients with conduction disturbances, ROC curves for TWRabsMedian as indicator of mortality exhibited areas under a curve of 0.66, 0.65, and 0.56 at 6-month, 24-month, and 35-month follow-up. Conduction disturbances were associated with increased nondipolar PCA component and, thus, with increased repolarization inhomogeneity. The nondipolar PCA component contained a moderate amount of prognostic information not present in a simple ECG diagnosis of a conduction disturbance.

Ischemia modified albumin improves emergency department chest pain risk stratification process

Study objectives: Many patients with suspected acute coronary syndrome (ACS) are admitted from the emergency department (ED) because of the insensitivity of presentation ECGs and troponin levels. Ischemia-modified albumin (IMA) is a novel cardiac biomarker of acute cardiac ischemia. The US Food and Drug Administration has approved the use of a normal IMA concentration in low-risk (per history/physical examination, ECG, and troponin) patients with chest pain syndrome as an indication for safe ED discharge. Methods: We reviewed all studies identified by computerized literature and obtained proprietary data from the assay manufacturer that evaluated IMA as an ACS “rule-out” in the ED setting. For trials to be included, patients were required to present to the ED within 3 hours of symptom onset. For each study, the appropriate IMA diagnostic cutoff was defined by receiver operating characteristic curve analysis or a normal range study. Studies eligible for inclusion were required to document discharge diagnosis with respect to cardiac ischemia or pertinent clinical outcomes for a minimum of 30 days after the index presentation. Results: There were 8 studies meeting eligibility criteria. Three trials evaluated all nontraumatic chest pain presentations; 4 studies evaluated low- to moderate-risk patients with nondiagnostic ECG and a negative troponin at presentation; and 1 study evaluated patients initially triaged as high risk and requiring a cardiology consult. IMA in conjunction with troponin and ECG at presentation had a high negative predictive value for ACS at the index visit and during the follow-up period: 84% in a high-risk population and 91% to 100% in the low-risk population. Conclusion: IMA has a high negative predictive value for short-term adverse outcomes in a preselected low- to moderate-risk population of patients with suspected ACS and may be used to facilitate contraction of the risk stratification process for chest pain syndrome in the ED. Study objectives: Many patients with suspected acute coronary syndrome (ACS) are admitted from the emergency department (ED) because of the insensitivity of presentation ECGs and troponin levels. Ischemia-modified albumin (IMA) is a novel cardiac biomarker of acute cardiac ischemia. The US Food and Drug Administration has approved the use of a normal IMA concentration in low-risk (per history/physical examination, ECG, and troponin) patients with chest pain syndrome as an indication for safe ED discharge. Methods: We reviewed all studies identified by computerized literature and obtained proprietary data from the assay manufacturer that evaluated IMA as an ACS “rule-out” in the ED setting. For trials to be included, patients were required to present to the ED within 3 hours of symptom onset. For each study, the appropriate IMA diagnostic cutoff was defined by receiver operating characteristic curve analysis or a normal range study. Studies eligible for inclusion were required to document discharge diagnosis with respect to cardiac ischemia or pertinent clinical outcomes for a minimum of 30 days after the index presentation. Results: There were 8 studies meeting eligibility criteria. Three trials evaluated all nontraumatic chest pain presentations; 4 studies evaluated low- to moderate-risk patients with nondiagnostic ECG and a negative troponin at presentation; and 1 study evaluated patients initially triaged as high risk and requiring a cardiology consult. IMA in conjunction with troponin and ECG at presentation had a high negative predictive value for ACS at the index visit and during the follow-up period: 84% in a high-risk population and 91% to 100% in the low-risk population. Conclusion: IMA has a high negative predictive value for short-term adverse outcomes in a preselected low- to moderate-risk population of patients with suspected ACS and may be used to facilitate contraction of the risk stratification process for chest pain syndrome in the ED.

Chest pain after recent stress test: Is there a warranty?

Study objectives: Emergency physicians often incorporate recent stress test results into their decisionmaking process for the evaluation and disposition of chest pain patients, which is based on studies of prognosis after stress testing. However, the subset of patients who present to an emergency department (ED) with chest pain and a history of a normal stress test is not adequately addressed in the literature. We seek to determine whether a history of a recent normal stress test result in patients presenting with chest pain to the ED is associated with a low risk (<1%) of major acute cardiac events. Methods: Patients presenting to our ED with a chief complaint of chest discomfort between January 1, 1998, and September 30, 2002, and who had undergone a stress test at our institution within 2 years were included. The primary endpoint was acute myocardial infarction on ED visit or death within 30 days. The diagnosis of acute myocardial infarction was based on cardiac marker elevation or ECG. All ECGs were reread for the purpose of this study by an investigator blinded to all other clinical data. Previous stress tests included treadmill studies without imaging, treadmill studies with imaging, and pharmacologic imaging studies. Treadmill study results were considered normal if there were no ST-segment changes and no abnormalities of functional capacity or heart rate dynamics during or after exercise. Imaging study results were considered normal if there was no evidence of myocardial ischemia or scar. Results: There were 1,857 eligible patients, of whom 283 had treadmill tests without imaging (79 or 27% were normal), 750 had treadmill tests with imaging (235 or 31% were normal), and 824 had pharmacologic tests (448 or 54% were normal). There were 190 patients (10%) who had the primary endpoint; only 2 patients died within 30 days. The history of a normal stress test was associated with a lower risk of the primary endpoint (50/762 or 7% versus 140/1095 or 13%, odds ratio 0.48, 95% confidence interval [CI] 0.34 to 0.67, <i>P</i><.0001). Among 449 patients who had a normal stress test result and on initial presentation had a nondiagnostic ECG and normal biomarkers, only 9 (2.0%, 95% CI 1.1% to 3.8%) had the primary endpoint. Among 508 patients who, on initial presentation, had a nondiagnostic ECG and normal biomarkers but had a history of an abnormal stress test result, 16 (3.2%, 95% CI 2.0% to 5.1%) had the primary endpoint. Conclusion: Among patients presenting with chest pain to the ED and a history of stress testing within the past 2 years, a normal stress test result was associated with a markedly reduced risk of having a major cardiac endpoint. However, with the possible exception of patients presenting with initially normal biomarkers and ECG findings, the absolute risk of 7% was not reassuringly low enough to justify early discharge.

Place du dosage des troponines

Cardiac troponin I and T are the newest biochemical gold standard in patients admitted with acute coronary syndrome. They are involved in the new biochemical definition of myocardial infarction. Their high sensitivity and specificity make them effective in detecting minor myocardial injury in patients with non-ST elevation myocardial infarction. As a result, troponins are useful as prognostic indicators and in the early identification of patients with a high risk of future cardiac events. Moreover, they may be useful in identifying patients who are likely to benefit most from adjunctive pharmacological therapy and invasive strategy. Troponins are of high clinical value in identifying or ruling out a diagnosis of myocardial infarction in emergency patients with a non-diagnostic ECG, and in patients undergoing cardiac or non cardiac surgery. Raised troponins may be observed also in non-ischemic diseases. This increase can have a prognostic value during pulmonary embolism and in patients with chronic renal failure. Highly selective immunoassays with anti-cardiac troponins monoclonal antibodies have been marketed. Standardization of troponin I assays are needed to achieve comparability of results among different assays. Current goal is the development of highly sensitive assays to detect even very minor myocardial lesions.

Radionuclide imaging in risk assessment after acute coronary syndromes

The National Service Framework for coronary artery disease1 acknowledged a role for myocardial perfusion imaging (MPI) in diagnosis and risk assessment of angina and quoted the cost-effectiveness data from the...

Hypertensive response to exercise in normotensives: special demographic and stress-test (related to cardiac autonomic nervous function) characteristics

P-479 Key Words: Hypertensive Response, Demographic Characteristics, Exercise Test Parameters ;;2>POSTERS: Neural Mechanisms and Transmitters

Early Myocardial Perfusion Gated-SPECT in Patients With Chest Pain and Non-Diagnostic ECG in the Emergency Department

To analyze the value of early resting myocardial perfusion gated-SPECT in patients with chest pain and non-diagnostic ECG in the emergency department. 222 patients (49% women, mean age 61 [13] years) with atypical chest pain and with non-diagnostic ECG were randomized into two groups. Group A comprised 111 patients in whom early resting myocardial perfusion gated-SPECT (<6 hours since the end of chest pain) was performed and CK-MB mass and troponin I were determined at 0, 4 and 8 hours. Group B comprised 111 patients with conventional management in the emergency department without gated-SPECT. Myocardial perfusion gated-SPECT was positive in all 8 patients with increased levels of CK-MB mass and troponin I. This corresponded to a sensitivity and a negative predictive value of 100% for the diagnosis of AMI. Specificity was 84% and positive predictive value was 33% when doubtful results were considered as negative. The number of patients admitted (18.4% vs 32.7%, P<.027) and length of stay (13 [6] hours vs 15.9 [8.6] hours, P<.009) in the emergency department were lower in group A. In patients with atypical chest pain and non-diagnostic ECG in the emergency department, early resting gated-SPECT was highly sensitive and showed good negative predictive value for the diagnosis of AMI, but positive predictive value was low. This technique may reduce the number of hospitalized patients and length of stay in the emergency department.

Reference values for cardiac troponins I and T in a goal-oriented concept of health: cardiac marker values in a series of outpatients without acute coronary syndromes

Background: Cardiac troponins are part of the new definition of acute myocardial infarction (AMI) by the European Society of Cardiology and the American College of Cardiology (ESC/ACC). In the new guidelines, it was suggested to establish reference values for cardiac troponins to calculate the 0.99 quantile (Q99) as cutoff for AMI diagnosis. Patients and methods: We run a prospective series of troponin measurements in unselected outpatients who had no suspicion of cardiac ischemia. The selection of patients as reference population is based on a “goal-oriented concept of health”. One hundred and ninety-five patients agreed that 10-ml additional blood was drawn at the occasion of the venous puncture done routinely in the evaluation of their case. Cardiac troponin I was measured using a point of care (POCT) device (Stratus CS®, DadeBehring, TNI-PO). Additionally, heparin-plasma was obtained and immediately deep-frozen to −80 °C for later batch measurement of cardiac troponin T (Elecsys® 2010, Roche Diagnostics, TnT) and troponin I (Centaur®, Bayer, TnI-CL). Results: The Q99 values were 0.14 μg/l for TnI-PO, 0.023 μg/l for TnT and 0.07 μg/l for TnI-CL in patients with creatinine levels below 1.5 mg/dl. These values lay above those obtained from people at good health for reference study purposes. On the level of our cutoffs, CVs were 7.5%, 6.4% and 23.7% for TnI-PO, TnT and TnI-CL, respectively. Conclusions: Only the TnI-PO and TnT tests fulfilled the imprecision criteria in our study. TnI-PO values between 0.10 and 0.14 μg/l and TnT values between 0.01 and 0.03 μg/l have to be interpreted carefully. Patients presenting with chest pain will be possibly true positives, but patients without chest pain and nondiagnostic ECGs should be subjected to repetitive troponin measurements and further noninvasive investigation and maybe not directly sent to the cardiac catheter laboratory.

Continuous 12-lead electrocardiographic monitoring in an emergency department chest pain unit: An assessment of potential clinical effect

Study objectives: Continuous 12-lead serial ECG monitoring has been proposed to assist in the evaluation of patients with acute coronary syndrome and nondiagnostic ECG in an emergency department chest pain unit. However, the ability of serial ECG to detect acute coronary syndrome and its benefit in addition to a standard protocol has not been established. We evaluate the ability of continuous 12-lead ECG to detect acute coronary syndrome, assess the incremental benefit of the serial ECG in association with a set protocol in an ED chest pain unit, and evaluate whether serial ECG changes could be considered as prognostic factors. Methods: Patients who met Agency for Health Care Policy and Research guidelines for intermediate risk for short-term cardiovascular event unstable angina were prospectively studied in the chest pain unit. Patients were monitored with the Mortara Instruments ELI 100 STM continuous 12-lead ECG system with ST-segment analysis. ST-segment changes of greater than 100 μV in 2 or more contiguous leads or greater than 200 μV in 1 lead were considered positive. Data were compared with serial serum cardiac markers, cardiac function study results, angiographic results, and 30-day outcome results. Results: One hundred nineteen patients had serial ECG applied. The median duration of monitoring was 4.2 hours. Forty patients were given a diagnosis of acute coronary syndrome. Chest pain unit protocol detected 52 patients, and 23 were given a diagnosis of acute coronary syndrome (sensitivity 58%; specificity 63%). Sixteen patients had ST-segment changes of greater than 100 μV or greater than 200 μV, and 9 were given a diagnosis of acute coronary syndrome. The addition of the serial ECG to the chest pain unit protocol increased the sensitivity to 65% and decreased the specificity to 58%. Two patients with ST-segment changes but none without ST-segment changes had an adverse cardiac event, yielding a sensitivity of 100% and a specificity of 88%. Conclusion: Serial ECG is of limited value in the diagnostic evaluation of intermediate-risk patients managed in the chest pain unit with a standard protocol. However, when ST-segment changes are present, they indicate an increased likelihood for an adverse cardiac event. [Ann Emerg Med. 2003;41:342-351.]

New Biochemical Tools for Diagnosing Acute Coronary Syndromes

This article reviews the value of myoglobin, troponins, and creatine kinase, MB fraction (CK-MB) in diagnosis, risk stratification, and prognosis in patients presenting to hospital emergency departments (ED) with symptoms suggestive of acute coronary syndromes. Because the three markers differ in specificities and their sensitivities vary with time after the onset of chest pain, the authors suggest that serial measurements for all three markers by point-of-care methods will optimize patient outcomes and reduce resource utilization. The rationale for this strategy is examined from the viewpoint of ED physicians who must make diagnoses, risk stratify patients, and make treatment decisions in patients presenting with non-diagnostic ECGs.

Magnetocardiography in Coronary Artery Disease with Nonspecific Electrocardiographic Finding

Background and Objectives:Magnetocardiography (MCG) is a noninvasive method for the registration of the magnetic component of electromagnetic fields in the heart that arise from electrical activity during the cardiac cycle. It has a theoretical advantage, over ECG, for the detection of coronary artery disease (CAD), mainly due to its higher sensitivity for local currents and better spatial resolution. However, its clinical value in the diagnosis of CAD, compared to other diagnostic tools, remains untested. The feasibility of MCG for detecting myocardial ischemia was studied. Subjects and Methods:Ninety three patients (54 male, 39 female) with chest pain were enrolled in this study. Patients with a pacemaker or other metal implants, as well as those in unstable conditions, were excluded. Coronary angiography was performed on all the patients, following ECG and MCG measurements, on the same day. Coronary artery disease was diagnosed when intraluminal narrowing was greater than 70%. The ECG and MCG findings were compared to those of the coronary angiography, which was used as the gold standard. Results: Forty two patients were diagnosed with CAD by the coronary angiography. The sensitivities and specificities of MCG and ECG for detecting a CAD were 76.2 and 47.1%, and 38.1 and 86.3%, respectively. Seventy patients showed non-diagnostic ECG for CAD. The sensitivity and specificity of MCG for detecting a CAD in this group of patients were 69.2 and 52.3%, respectively. Conclusion:MCG is a novel noninvasive technique for the diagnosis of coronary artery disease, but further investigation for the optimization of the efficacy of this technology will be required. (Korean Circulation J 2003;33 (9):779-785)

Diagnostic parameters of CK–MB and myoglobin related to chest pain duration

Cardiac marker sensitivity depends on chest pain duration at the time of sampling. Our objective was to estimate the sensitivity, specificity, and likelihood ratios of early CK-MB and myoglobin assays in patients presenting to the emergency department (ED) with nondiagnostic ECGs, stratified by the duration of ongoing chest pain at the time of ED assessment. This was a prospective observational study carried out in 10 US and 2 Canadian EDs. Patients >25 years of age with ongoing chest pain and nondiagnostic ECGs were stratified by pain duration (0-4 h, 4-8 h, 8-12 h, >12 h). CK-MB and myoglobin assays were drawn at T = 0 (ED assessment) and T = 1 hr. Patients were followed for 7-14 days to identify all cases of acute myocardial infarction (AMI). ED test results were correlated with patient outcomes. Of 5005 eligible patients, 565 had AMI. Pain duration was 0-4 h in 3014 patients, 4-8 h in 961, 8-12 h in 487, and >12 h in 543. Marker sensitivity increased with pain duration, ranging from 28%-77% for CK-MB and 39%-73% for myoglobin. The maximal sensitivity achieved by a T = 0 assay was 73%, and this was in patients with 8-12 or >12 h of ongoing pain. No combination of tests achieved 90% sensitivity in any pain duration strata. Regardless of chest pain duration, single assays and early serial markers (0+1 hr) do not rule out AMI; therefore, serial assays over longer observation periods are required. Likelihood ratios derived in this study will help physicians who use Bayesian analysis to determine post-test AMI likelihood in patients with chest pain.

QT dispersion measured by an automatic continuous method early in patients admitted for chest pain

Background: There is a need for risk markers in patients with acute chest pain. QT dispersion (QTd) is a prognostic marker in several groups of patients. A problem with the manual measurement of QTd is operator dependency. This can be avoided by using an automatic method. We investigated QTd, derived from multiple automatic measurements, as a risk marker in a population with chest pain. Methods: In 548 patients admitted to the coronary care unit for chest pain and nondiagnostic ECG, 12-lead ECG recordings were collected each minute during the initial 17 h. From recordings with ≥10 valid leads, mean QTd (QTdMean), QTd in the first satisfactory recording and estimates of variability of QTd were computed and correlated to outcome. Results: In the group with QTdMean ≥40 ms ( n=277), 10 patients died during the initial 30 days; one patient died in the group with QTdMean <40 ms ( n=271) ( P=0.07). During follow-up (median 6 months), 19 vs. five patients died in each group ( P=0.03). The figures for the triple endpoint death/myocardial infarction/revascularisation were 52 vs. 27 events during the initial 30 days ( P=0.018) and 76 vs. 41 events during follow-up ( P=0.003). QTd in the first recording did not predict new cardiac events. Conclusions: QTd measured as the mean value of multiple recordings was found to be a powerful marker for cardiac events during follow-up. It was superior to the analysis of QTd in a single ECG. It can be used for the selection of low-risk patients, but was not effective in identifying high-risk patients.

Prognostic value of 2D echocardiography in patients presenting with acute chest pain and non-diagnostic ECG for ST-elevation myocardial infarction

The purpose of the present study was to test the hypothesis that early detection of regional wall motion abnormalities (WMA) by 2D echocardiography (ECHO) accurately predicts further cardiac events in patients presenting with acute chest pain. A prospective analysis was performed in subjects admitted with the first presentation of acute chest pain and a non-diagnostic ECG for acute ST-elevation myocardial infarction. Patients with known coronary artery disease were excluded. All subjects were contacted by phone for a 30days follow-up regarding cardiac events defined as PCI/CABG, AMI, and death. In 132 consecutive patients (89 male, 43 female) complete data sets consisting of case history (H; abnormal: typical angina), ECG (abnormal: ST-depression, T-inversion, atypical ST-elevation, LBBB), serum markers (TnI; abnormal: elevation of troponin I=0.5 ng/ml), ECHO (abnormal: WMA) and follow-up were available. In 45 patients, 60 cardiac events occurred (three deaths, 24 AMI, 33 PCI/CABG). Positive (PPV; %) and negative predictive values (NPV; %) of ECHO were superior to all other diagnostic tests ( P<0.05 each) for adverse cardiac events, evolving AMI or death, and superior to history and ECG for later need of revascularisation (PCI/ACVB). Multivariate analysis revealed that WMA in ECHO predict cardiac events independently of age, gender, and the common combination of investigations (H/ECG/TnI). A significant independent impact of ECHO was also determined for the prediction of AMI/death or PCI/CABG. The study shows that early 2D echocardiography provides superior prognostic information concerning the risk of subsequent complications in patients with acute chest pain and a non-diagnostic ECG for ST-elevation–AMI.

Chest pain unit management of patients at low and not low-risk for coronary artery disease in the emergency department. A 5-year experience in the Florence area.

In this study, we screened a total of 6723 consecutive patients with chest pain and ECG non-diagnostic for acute myocardial infarction (AMI) on presentation to the emergency department (ED). The aim of the study was to avoid missed AMI, improve safe early discharge and reduce inappropriate coronary care unit (CCU) admission. Chest pain patients were triaged using a clinical chest pain score and managed in a chest pain unit (CPU). Patients with a low clinical chest pain score were considered at very 'low-risk' for cardiovascular events and discharged from the ED; patients with a high chest pain score were submitted to CPU management. Observation and titration of serum markers of myocardial injury were obtained up to 6 hours. Rest or stress myocardial scintigraphy (SPECT) was performed in patients > 40 years or with > or = 2 major coronary risk factors. Exercise Tolerance Test (ETT) or Stress-Echocardiogram (stress-Echo) were performed in younger patients or with < 2 coronary risk factor, or unable to exercise, respectively We discharged directly from the ED the majority of patients (4454; 66%): in this group there was only a 0.2% final diagnosis of coronary artery disease (CAD) at follow-up. The remaining 34% of patients, with non-diagnostic or normal ECG, were managed in the CPU. In this group, 1487 patients (representing 22% of the overall study group) were found positive for CAD, two-thirds because of delayed ECG or serum markers of myocardial injury, and one-third by Echo, SPECT or ETT. In conclusion, CPU based management allowed 22% early detection of myocardial ischaemia and 78% early discharge from the ED avoiding inappropriate CCU admission and optimizing the use of urgent angiography.

Unidades de dolor torácico. Organización y protocolo para el diagnóstico de los síndromes coronarios agudos

The two main goals of chest pain units are the early, accurate diagnosis of acute coronary syndromes and the rapid, efficient recognition of low-risk patients who do not need hospital admission. Many clinical, practical, and economic reasons support the establishment of such units. Patients with chest pain account for a substantial proportion of emergency room turnover and their care is still far from optimal: 8% of patients sent home are later diagnosed of acute coronary syndrome and 60% of admissions for chest pain eventually prove to have been unnecessary.We present a systematic approach to create and manage a chest pain unit employing specialists headed by a cardiologist. The unit may be functional or located in a separate area of the emergency room. Initial triage is based on the clinical characteristics, the ECG and biomarkers of myocardial infarct. Risk stratification in the second phase selects patients to be admitted to the chest pain unit for 6-12 h. Finally, we propose treadmill testing before discharge to rule out the presence of acute myocardial ischemia or damage in patients with negative biomarkers and non-diagnostic serial ECGs.

Early detection of myocardial ischaemia in the emergency department by rest or exercise 99mTc tracer myocardial SPET in patients with chest pain and non-diagnostic ECG

Chest pain (CP) represents a frequent reason for presentation at the emergency department (ED). A large proportion of patients have non-diagnostic ECG on presentation, and in many cases several hours have elapsed since onset of symptoms. Acute rest myocardial scintigraphy (rest SPET) has been shown to have a relevant role in the detection of patients at risk for coronary events, but its sensitivity and negative predictive value are optimal only within the first 3 h following onset of symptoms. In those with delayed presentation, exercise SPET alone, as a screening approach, appears more promising, but its feasibility and diagnostic role in the ED are still unresolved. A total of 231 consecutive patients with a recent-onset (<24 h) first episode of CP had a negative first-line work-up including ECG, troponins, creatine kinase-MB and echocardiography. These patients were considered at low risk for short-term coronary events. Patients were studied with rest SPET if they presented <3 h after onset of CP and exercise SPET if they presented after > or =3 h. The end-points of the study were detection of significant coronary artery disease (CAD) by angiography and major coronary events or cardiac death at 6 months. Eighty patients (35%) underwent rest SPET, while 151 (65%) underwent exercise SPET. Two of the 159 patients with negative SPET had evidence of critical CAD at 6-month follow-up (one patient in the rest SPET group and one in the exercise SPET group; P=NS). Of the 72 patients (31%) with a positive scan, 34 (15%) had documented CAD (16 patients in the rest SPET group and 18 in the exercise SPET group; P=NS). Sensitivity, specificity, accuracy and predictive value were not statistically different between the two groups. In conclusion, the accuracy of exercise SPET in patients with CP and delayed presentation to the ED is comparable to that of validated rest SPET in patients with early presentation. Owing to the high negative predictive value (99%), exercise SPET is especially valuable as a screening tool for the exclusion of CAD in low-risk patients and implementation of early discharge.