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Assessment of the Standardized Reporting Guidelines ECG Classification System: The Presenting ECG Predicts 30-Day Outcomes ANNALS OF EMERGENCY MEDICINE 4 4 : 3 SEPTEMBER 2004 INTRODUCTION Chest pain at ED: 1/3 cardiac cause Inappropriate discharge leads to medical error Many studies for better methods to risk-stratify: none widespread accepted Current draft of guidelines (Standardized Reporting Criteria Working Group of the Emergency Medicine Cardiovascular Research and Education Group): recommend ECG classified into 1 of 6 categories Evaluate recommended classification system to predict endpoint of death, MI, revascularization within 30 days MATERIALS AND METHODS Study Design Prospective study Setting July 1999 to March 2002: Hospital of the University of Pennsylvania, urban tertiary care hospital ED in Philadelphia Included: >24 y/o or <24 y/o with cocaine use, with chest pain prompting an ECG Excluded: <24 y/o, without chest pain, chest pain without ECG. MATERIALS AND METHODS Data Collection and Processing Information: directly from the treating physician Demographic characteristics, cardiac risk factors, chest pain characteristics, associated symptoms, medications, initial vital signs, treatment, disposition. Daily f/u for death, MI, revascularization for 30 days MATERIALS AND METHODS Standardized Reporting Criteria Standardized Reporting Criteria Working Group of the Emergency Medicine Cardiovascular Research and Education Group 47 ‘core characteristics’ organized into 8 major reporting categories: inclusion criteria, demographic characteristics, ECG interpretation, cardiac risk factors, chief complaint, cardiac markers, patient course, outcomes. Figure 1. Electrocardiographic core criteria advocated by the guidelines. Report who interpreted the ECGs. The investigator should clarify whether the ECG interpretation was done by the clinician when patient care was provided or by an investigator after patient enrollment in the study. ECG analysis should be reported in terms of specific findings suggestive of acute coronary syndrome. Rate Rhythm ST-segment elevation and depression (and unit of deviation: 1 vs 2 mm/mV). Should be reported as ‘‘known to be old’’ or ‘‘not known to be old.’’ T-wave inversion (should report standardized depth). Should be reported as ‘‘known to be old’’ or ‘‘not known to be old.’’ Left bundle-branch block (presence or absence). Should be reported as ‘‘known to be old’’ or ‘‘not known to be old.’’ Right bundle-branch block (presence or absence). Should be reported as ‘‘known to be old’’ or ‘‘not known to be old.’’ Report overall categorization of the ECG Normal Nonspecific Abnormal but not diagnostic of ischemia Ischemia known to be old Ischemia or previous infarction not known to be old ST elevation consistent with acute myocardial infarction The definitions assigned to each category are as follows: Normal: no possible evidence for ischemia Nonspecific: accepted deviation from the norm, with the lowest likelihood of ischemia (eg, inverted T-wave axis in III or V1) Abnormal but not diagnostic of ischemia: prolonged PR, QRS, QTc intervals, bundle branch blocks, left ventricular hypertrophy with strain Ischemia or previous infarction not known to be old: ST-segment depression >0.1 mV measured 80 ms from the J point, inverted T waves >0.3 mV, or Q waves 30 ms in duration Ischemia or previous infarction known to be old Suggestive of acute myocardial infarction: ST elevation >0.1 mV measured 80 ms from the J point in 2 contiguous leads, with or without reciprocal ST depressions. MATERIALS AND METHODS Outcome Measures Include physicians of all specialties rotating to ED at all levels of training Assess whether the proposed classification system is generalized to any treating physician. 5 categories in this study: (1) normal (2) early repolarization without other abnormalities (3) abnormal but not diagnostic of ischemia: prolonged PR, QRS, or QTc, BBB, LVH with strain, nonspecific intraventricular conduction deficits, NSSTTC (4) ischemia: STD > 0.1 mV, 80 ms from J, TWI > 0.3 mV, Q wave at least 30 ms (5) suggestive of MI: STE > 0.1 mV, 80 ms from J in > 2 contiguous leads, with or without reciprocal change MATERIALS AND METHODS Diagnosis of AMI: troponin I >= 2 ng/mL, CK-MB >=10 ng/mL Revascularization: PCI, bypass Death: all-cause mortality. Primary Data Analysis ECG classification category in relation to rate of death, MI, revascularization within 30 days SAS statistical software Patient with multiple ED visits: each visit counted separately, evaluated as an individual event MATERIALS AND METHODS Standardized reporting guidelines not available in beginning: ECG classification in study slightly different. Standardized: Normal, Nonspecific, Abnormal but not diagnostic of ischemia, Ischemia known to be old, Ischemia or previous infarction not known to be old, ST elevation consistent with acute myocardial infarction Normal, ischemia, suggestive of MI: identical to guidelines Abnormal nondiagnostic: nonspecific, abnormal nondiagnostic Further analysis in final: ST, T-wave changes or BBB: abnormal nondiagnostic, without: nonspecific. RESULTS Demographic characteristics of the patient population. Characteristic Study Patients,No. (%) (N=4,487 Visits) Mean age (6SD), y* 51.86+-15.9 Ethnicity* Asian 69 (2) Black 2,611 (68) Hispanic 43 (1) Other/unknown 31 (1) White 1,060 (28) Sex* Male 1,547 (41) Female 2,267 (59) Cardiac risk factors Hypertension 2,192 (49) Family history of premature coronary artery disease 903 (20) Diabetes mellitus 805 (18) Tobacco use 1,684 (38) Hypercholesterolemia/hyperlipidemia 789 (18) Cocaine use 104 (2) Previous myocardial infarction 497 (11) Known coronary artery disease 878 (20) *Age, sex, and ethnicity are counted only once per patient (n=3,814), regardless of the number of visits. RESULTS 1,672 (37%) patients: discharged; 2,147 (48%) admitted to telemetry, 496 (11%): ICU, 134 (3%): unmonitored beds, 14 (<1%): catheterization; 13: AAD, 10: transfer. Cardiac markers obtained in 3,262 (73%) patient visits. RESULTS Details of the presenting ECG. Characteristic* Study Patients,No. (%) (N=4,487) Overall ECG impression Normal 1,912 (43) Early repolarization only 171 (4) Nonspecific/nondiagnostic changes 2,081 (50) Ischemia 224 (5) Acute myocardial infarction 99 (2) ST-segment elevation >1 mm 420 (9) ST-segment depression >0.5 mm 338 (8) T-wave inversion >5 mm 885 (20) Hyperacute T waves 115 (3) Pathologic Q waves 261 (6) Left bundle-branch block 90 (2) Right bundle-branch block 125 (3) * Specific definitions were used for the classification system, ST-segment elevation, ST-segment depression, and T-wave inversion. There were no specific definitions onthe case report forms for the other items. RESULTS Most: nonspecific, nondiagnostic Initial hospital course: 318 (7%) AMI, additional 545 (12%) unstable angina, 28 died, 11 late MI (>24 hours), 111 PCI, 26 CABG, 399 meet endpoint (death, MI, revascularization) 98% 30 days follow-up, 446 patients meet endpoint, 52 deaths, 30 MI, 17 PCI, 11 CABG. Significant (P<.0.01) relationship between initial ECG classification and 30-day outcome. Further analysis in abnormal nondiagnostic: nonspecific, abnormal nondiagnostic ST, T-wave abnormalities, BBB: higher risk than patients without these LIMITATIONS ECG classification system in this study: not exactly match recommended classification guidelines. Subset analysis in abnormal but not diagnostic: different prognosis between with and without ST, T-wave changes. Presenting ECG vs outcome: additional ECGs would be better? Whether ECGs were obtained during chest pain attack? A triple composite outcome not individual: need more samples Population predominantly black DISCUSSION Developing standardized reporting guidelines for risk- stratification in potential acute coronary syndromes. Include 8 major reporting categories with 47 core criteria: 9 of these are electrocardiographic criteria. High interrater reliability in this recommend ECG classification system: presenting ECG classification predicts inhospital, 30-day triple composite endpoint (death, MI, revascularization) Similar ECG interpretation schemes in predicting short- term complication in critical care populations, AMI in older ED chest pain populations. DISCUSSION Normal, nonspecific ECG: low risk short-term cardiovascular complications. Ischemia: higher risk Abnormal but nondiagnostic: intermediate risk, Further analysis: lower risk in nonspecific then abnormal but nondiagnostic Conclusion: 6-item ECG classification system recommended in the standardized guidelines predicts 30-day rates of death, acute myocardial infarction, revascularization. THNAKS FOR YOUR ATTENTION.
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