Can Electrocardiographic Criteria Predict Adverse Cardiac Events and Positive Cardiac Markers?

OBJECTIVES: To determine electrocardiogram (ECG) predictors of positive cardiac markers and short-term adverse cardiac events in an undifferentiated chest pain population presenting to emergency departments (EDs). The authors hypothesized that specific ECG findings, other than those previously identified in higher-risk populations, would be predictive of cardiac outcomes and positive cardiac markers. METHODS: This study used data from a prospectively collected, retrospectively analyzed Internet-based data registry of undifferentiated chest pain patients (i*trACS). Logistic regression modeling was performed to determine the ECG findings that were predictive of 1) positive cardiac markers and 2) short-term adverse cardiac events. RESULTS: ST-segment elevation (STE), ST-segment depression (STD), pathological Q-waves (PQW), and T-wave inversion were associated with increased odds of percutaneous coronary intervention or catheterization, myocardial infarction, or coronary artery bypass grafting. The odds of creatine kinase-MB (CK-MB) measuring positive were increased if STE, STD, or PQW were present [odds ratio (OR) 2.495, 2.582, and 1.295, respectively]. A right bundle branch block tended to decrease the odds of CK-MB measuring positive (OR 0.658). A similar pattern of results was observed for troponin I (OR 3.608 for STE, 3.72 for STD, 1.538 for PQW). Troponin T showed an increased odds of measuring positive if any of STE, STD, left bundle branch block, or T-wave inversion were evident (OR 2.313, 2.816, 1.80, and 1.449, respectively). CONCLUSIONS: Initial ECG criteria can be used to predict short-term cardiac outcomes and positive cardiac markers. These findings can be important aids in the risk-stratification and aggressive treatment regimens of chest pain patients presenting to EDs.     

ST elevation measurements differ in patients with inferior myocardial infarction and right ventricular infarction

Purpose

Few studies specify the methods used to measure ST-segment elevation (STE). We therefore assessed differences in electrocardiography results depending on STE measurement methods for patients with inferior acute myocardial infarction (MI) and right ventricular infarction.

Methods

This study was a retrospective analysis. The STE group consisted of 88 patients consecutively admitted to the emergency department with inferior ST elevation MI associated with occlusion of right coronary artery or left circumflex coronary artery who underwent primary percutaneous coronary intervention. The control group consisted of 109 patients with non-ST elevation MI who had occlusion of right coronary artery or left circumflex coronary artery and underwent percutaneous coronary intervention. Measurements were performed at the J point and 60 milliseconds later for limb lead and right precordial V₄ lead (V4R). The criterion of at least 1-mm STE in 2 consecutive leads was applied, and the diagnostic accuracy of V4R was calculated.

Results

In the STE group, the measurements 60 milliseconds after the J point were significantly higher than measurements at the J point at the II, III, aVF, and V4R leads. In the control group, only the measurements at lead I differed significantly. There was a 5% difference in diagnostic sensitivity depending on the measuring points in the STE group, a 1% to 3% difference in the control group, and a 10% to 11% difference at the V4R lead.

Conclusion

In patients with inferior MI, STE depends on the method of measurement, indicating a need for the standardization of measurements.     

Successful resuscitation with extracorporeal membrane oxygenation support for refractory ventricular fibrillation caused by left main coronary artery occlusion

Refractory ventricular fibrillation with cardiac arrest caused by occlusion of the left main coronary artery may rapidly become fatal. In this report, we describe the case of a 70-year-old male who presented to emergency department with chest pain. Electrocardiogram showed ST-segment elevation in leads aVR and aVL and ST-segment depression in leads v3, v4, v5, v6, 2, 3, and aVF. Occlusion of the left main coronary artery was suspected. While waiting for percutaneous coronary intervention, the patient experienced sudden refractory ventricular fibrillation with cardiac arrest. In the emergency department, resuscitation of a patient with refractory ventricular fibrillation caused by occlusion of the left main coronary artery and ongoing cardiopulmonary resuscitation is a clinical challenge. Resuscitation with extracorporeal membrane oxygenation support was initiated approximately 35?min after prolonged conventional cardiopulmonary resuscitation. Emergency coronary angiography showed almost total occlusion of the left main coronary artery. Percutaneous coronary intervention with a stent restored coronary perfusion. The patient was discharged on day 6 without serious sequelae or neurological deficits.     

Which chest pain patients potentially benefit from continuous 12-lead ST-segment monitoring with automated serial ECG?

A prospective observational study was performed in 678 chest pain patients with suspected acute coronary ischemic syndrome (ACS) and absence of clinical and ECG criteria for emergent reperfusion therapy on presentation to determine how often continuous 12-lead ST-segment monitoring with automated serial ECG (SECG) results in a significant change in therapy during the initial emergency department (ED) evaluation in typical high- and low-risk chest pain patients. After initial history, physical, and ECG were obtained, patients were grouped into high and low risk subgroups based on ED physician's assessment of likelihood of ACS. Significant change in therapy was defined as thrombolytic drug administration, emergent percutaneous coronary angioplasty (PTCA), and intensive anti-ischemic therapy with intravenous heparin and/or intravenous nitroglycerin. SECG monitoring was continued until either the patient was taken for emergent PTCA or until 2-hour serum markers measurements were obtained. A total of 26 patients therapy was changed secondary to SECG monitoring which represented 14.6% of high-risk patients and 1.1% of low-risk patients. New injury (21 patients) and new ischemia (4 patients) were the only SECG findings that led to a change in therapy. SECG monitoring had a 15.2 times increased odds of changing therapy in the high risk patients as compared with the low risk patients (P < .0001; 95% CI 6.1 to 38.2). Chest pain evaluation protocols that exclude these high risk ED patients from SECG monitoring should be reevaluated. Our data also suggests that researchers designing randomized studies to show utility of SECG monitoring should focus on the high-risk patients.     

Pre-hospital body surface potential mapping improves early diagnosis of acute coronary artery occlusion in patients with ventricular fibrillation and cardiac arrest

Aims

To determine whether 80-lead body surface potential mapping (BSPM) improves detection of acute coronary artery occlusion in patients presenting with out-of-hospital cardiac arrest (OHCA) due to ventricular fibrillation (VF) and who survived to reach hospital.

Methods and results

Of 645 consecutive patients with OHCA who were attended by the mobile coronary care unit, VF was the initial rhythm in 168 patients. Eighty patients survived initial resuscitation, 59 of these having had BSPM and 12-lead ECG post-return of spontaneous circulation (ROSC) and in 35 patients (age 69 ± 13 yrs; 60% male) coronary angiography performed within 24 h post-ROSC. Of these, 26 (74%) patients had an acutely occluded coronary artery (TIMI flow grade [TFG] 0/1) at angiography. Twelve-lead ECG criteria showed ST-segment elevation (STE) myocardial infarction (STEMI) using Minnesota 9-2 criteria – sensitivity 19%, specificity 100%; ST-segment depression (STD) ≥0.05 mV in ≥2 contiguous leads – sensitivity 23%, specificity 89%; and, combination of STEMI or STD criteria – sensitivity 46%, specificity 100%. BSPM STE occurred in 23 (66%) patients. For the diagnosis of TFG 0/1 in a main coronary artery, BSPM STE had sensitivity 88% and specificity 100% (c-statistic 0.94), with STE occurring most commonly in either the posterior, right ventricular or high right anterior territories.

Conclusion

Among OHCA patients presenting with VF and who survived resuscitation to reach hospital, post-resuscitation BSPM STE identifies acute coronary occlusion with sensitivity 88% and specificity 100% (c-statistic 0.94).     

ST Segment Elevation Differs Depending on the Method of Measurement

Objectives: The literature seldom specifies the location or method of measurement of ST segment elevation (STE) for determining eligibility in reperfusion trials. The objective of this study was to assess if different methods of measurement of STE in precordial leads of patients with anterior acute myocardial infarction due to left anterior descending occlusion result in significantly different scores.
Methods: This was a retrospective review of diagnostic electrocardiograms (ECGs) of consecutive patients presenting to our emergency department with acute myocardial infarction who had emergent primary percutaneous coronary intervention, left anterior descending occlusion, and no bundle branch block. STE was measured at the J point and at 60 milliseconds after the J point, relative to the PR segment, in leads V1–V6. STE by the two methods was compared for each lead, as were ST scores (sum of STE in leads V1–V6) and the sum of the STE in V2–V4. Eligibility for reperfusion therapy using 1-mm and 2-mm STE criteria in two consecutive anterior leads, as well as ST scores and the sum of the STE in V2–V4, were evaluated.
Results: Thirty-seven ECGs were analyzed. Mean ST measurements in every lead were significantly lower when measured at the J point versus 60 milliseconds after the J point, as were ST scores (9.7 ± 2.14 mm vs. 14.9 ± 2.69 mm; p < 0.00001). Fewer ECGs met enrollment criteria when based on STE at the J point versus at 60 milliseconds after the J point. Fewer ECGs met an ST score of 6 mm when measured at the J point (70% vs. 88%).
Conclusions: In anterior STE myocardial infarction, STE measurements produce different results depending on the method of measurement. Future clinical trials should specify the method of measurement.     

Contemporary diagnosis and management of unstable angina

Unstable angina (UA) is one of the acute coronary syndromes, a group of conditions that also includes non-ST elevation myocardial infarction (MI) and ST elevation MI. The underlying pathogenic substrate of all these entities is the unstable coronary plaque with an overlying intracoronary thrombus. Initial management for the patient with suspected UA includes a resting electrocardiogram and oral administration of aspirin. ST-segment elevation indicates acute MI with the need for urgent reperfusion therapy. Patients without ST-segment elevation commonly have a mixture of UA and non-ST elevation MI; initial management is similar with assessment of near-term risk of MI or death as the next step. Features of UA indicating high risk include persistent ST-segment depression, persistent ischemic pain, elevated troponin level, or features of heart failure. Such patients undergo intensive medical therapy with heparin (unfractionated or low-molecular-weight), beta-blockade, and IIb/IIa antiplatelet agents, usually followed by coronary angiography and percutaneous intervention. The timing of intervention depends on the patient's response to therapy. Intermediate- or low-risk patients (including those presenting to the emergency department) can be managed with a chest pain unit strategy, and those with normal results on serial electrocardiograms, cardiac marker studies, and functional testing can be safely discharged home. Others are admitted for elective angiography, intensive medical therapy, or both. Assessment of coronary risk factors and their modification is an important component of long-term therapy for both high-risk and low-risk patients with UA, as well as those determined to have had non-ST elevation MI.     

Severe hypocalcemia simulating ST-elevation myocardial infarction

ST-elevation myocardial infarction (STEMI) is an emergency situation in which immediate measures for myocardial reperfusion are needed. The diagnosis is based on the recognition of ST-segment elevation in the electrocardiogram (ECG). In case of coronary artery occlusion, ST-segment elevation is caused by an injury current from the ischemic myocardium. Rarely, other mechanisms may lead to ECG changes mimicking STEMI. In our case, a 65-year-old man was presented to our institution with ECG abnormalities suggestive of STEMI. However, coronary angiography showed open arteries. Laboratory tests revealed severe hypocalcemia caused by a deficiency of vitamin D. After calcium replacement therapy, the ECG normalized, and the patient was discharged in good condition. Only a few case reports on hypocalcemia-induced ST-segment elevation exist, and the mechanism remains unknown.     

Syncope with ST-segment abnormalities resembling Brugada syndrome due to reversible myocardial ischemia

This report describes a case of syncope with an initial ECG that showed ST-segment elevation in the right precordial leads suggestive of Brugada syndrome. Procainamide infusion induced a significant increase in the ST-segment abnormalities, further increasing the suspicion for this syndrome. Cardiac catheterization showed lesions in the proximal left anterior descending artery and distal right coronary artery. Following percutaneous coronary intervention at these sites, the ST-segment abnormalities resolved and a repeat procainamide challenge was negative. Electrophysiological study did not provoke any ventricular arrhythmias. Silent myocardial ischemia may result in ECG changes that resemble those seen in patients with Brugada syndrome.     

Discriminating between right coronary artery and circumflex artery occlusion by using a noninvasive 18-lead electrocardiogram.

BACKGROUND: Differentiating occlusion of the circumflex branch of the left coronary artery (also called the circumflex artery) from occlusion of the right coronary artery is often difficult because either may be associated with a pattern of acute inferior myocardial infarction on the electrocardiogram. OBJECTIVES: To determine if an inexpensive 18-lead electrocardiogram can provide useful information in differentiating sites of coronary occlusion. METHODS: Continuous 18-lead electrocardiograms, including standard 12-lead, right ventricular, and posterior leads, were recorded in 38 and 50 subjects undergoing percutaneous coronary interventions in the right coronary artery and the circumflex artery, respectively. RESULTS: ST-segment elevation in the posterior leads was twice as frequent during occlusion of the circumflex artery as during right coronary occlusion (P < .001). ST-segment elevation in the right ventricular leads and inferior leads occurred more often during occlusion of the right coronary artery than during occlusion of the circumflex artery. ST-segment depression in lead aVL is highly suggestive of right coronary occlusion, whereas ST-segment elevation in posterior leads without depression of the ST segment in lead aVL is highly sensitive and specific for occlusion of the circumflex artery. CONCLUSIONS: ST-segment changes in the 18-lead electrocardiogram can be used to differentiate between occlusions of the circumflex artery and occlusions of the right coronary artery. Knowing which vessel is occluded before percutaneous coronary intervention can help in planning the procedure and recognizing when patients are at high risk for disturbances in conduction at the atrioventricular node.     

Chest pain showing precordial ST-segment elevation in a 96-year-old woman with right coronary artery occlusion: A case report

BACKGROUNDTypically, right coronary artery (RCA) occlusion causes ST-segment elevation in inferior leads. However, it is rarely observed that RCA occlusion causes ST-segment elevation only in precordial leads. In general, an electrocardiogram is considered to be the most important method for determining the infarct-related artery, and recognizing this is helpful for timely discrimination of the culprit artery for reperfusion therapy. In this case, an elderly woman presented with chest pain showing dynamic changes in precordial ST-segment elevation with RCA occlusion.CASE SUMMARYA 96-year-old woman presented with acute chest pain showing precordial ST-segment elevation with dynamic changes. Myocardial injury markers became positive. Coronary angiography indicated acute total occlusion of the proximal nondominant RCA, mild atherosclerosis of left anterior descending artery and 75% stenosis in the left circumflex coronary artery. Percutaneous coronary intervention was conducted for the RCA. Repeated manual thrombus aspiration was performed, and fresh thrombus was aspirated. A 2 mm × 15 mm balloon was used to dilate the RCA with an acceptable angiographic result. The patient’s chest pain was relieved immediately. A postprocedural electrocardiogram showed alleviation of precordial ST-segment elevation. The diagnosis of acute isolated right ventricular infarction caused by proximal nondominant RCA occlusion was confirmed. Echocardiography indicated normal motion of the left ventricular anterior wall and interventricular septum (ejection fraction of 54%), and the right ventricle was slightly dilated. The patient was asymptomatic during the 9-mo follow-up period.CONCLUSIONCardiologists should be conscious that precordial ST-segment elevation may be caused by occlusion of the nondominant RCA.     

急诊经皮冠状动脉介入治疗术前心电图参数对术后心肌再灌注水平的预测价值

目的探讨急性ST段抬高型心肌梗死（STEMI）患者经皮冠状动脉介入治疗（PCI）术前心电图参数预测急诊PCI术后的心肌再灌注水平的价值,寻找能够尽早提示急诊PCI术后疗效的检测手段。方法回顾性分析65例行急诊PCI术的急性STEMI患者发病时心电图的各项参数与术后心肌梗死溶栓治疗（TIMI）分级的相关程度,筛选无复流现象的独立危险因素。结果65例急诊PCI患者中,无复流患者17例,发生率为26．2％。比较无复流组与正常血流组患者的术前心电图参数,ST段抬高类型差异有统计学意义（P〈0．05）,以ST段呈C型抬高者无复流发生率最高（34．8％,16／46）;而QRS记分、ST段抬高导联数目、ST段抬高总和差异无统计学意义。多因素logistic回归分析表明：C型ST段抬高是无复流现象发生的独立危险因素（OR=8．956,95％CI=1．189,67．456,P=0．033）。结论作为一项简明的心电图参数,C型ST段抬高可以预测急诊PCI术后冠状动脉无复流现象,有利于术前、术中预见性地采取防治该现象的措施。     

Fibrinolysis in patients with acute coronary syndrome

The reperfusion therapy including both fibrinolytic therapy and primary percutaneous coronary intervention (PCI) has been established in patients with ST-segment elevation acute myocardial infarction (STEMI). Fibrinolysis has the advantage of universal availability and short time to administration. Because the benefit of fibrinolysis is directly related to the time from symptom onset to treatment as demonstrated in many studies, every effort must be made to minimize any delays between symptom onset and the initiation of a safe and effective reperfusion strategy in patients with STEMI. Although the benefit of fibrinolysis is limited by inadequate reperfusion or reocclusion of the infarct-related artery in a sizable portion of patients, fibrinolysis followed by planned PCI can be one of approaches in patients presenting within 2 or 3 hours from onset of STEMI.     

急性ST段抬高型心肌梗死经桡动脉急诊经皮冠状动脉介入治疗23例

目的评价经桡动脉途径急诊经皮冠状动脉介入治疗(PCI)治疗急性ST段抬高型心肌梗死(STEAMI)的临床疗效。方法对23例STEAMI患者在发病12 h内行急诊PCI治疗,23例植入支架。结果 STEAMI患者23例中,手术后获得前向血流TIMI 3级23例(100%),存活的23例患者术后随访30 d,无一例发生再次心肌梗死或死亡。结论经桡动脉途径行急诊PCI治疗STEAMI,成功率高,住院病死率低,近期预后良好。     

A case of myocardial infarction due to acute left main coronary artery occlusion presenting with peculiar electrocardiographic changes

Myocardial infarction (MI) due to acute obstruction of the left main coronary artery (LMCA) occlusion is a medical emergency, requiring early and prompt diagnosis and revascularization, and unless it is treated, it will frequently result in cardiogenic shock, which has a high fatality rate. Our case focused on a patient, who was transferred to our hospital relatively late due to peculiar ECG. He had acute MI, and was in cardiogenic shock. ECG is the easiest diagnostic method in the early diagnosis of the acute coronary syndromes and in deciding on the early invasive intervention in the high risk group. Before he was sent to us, the patient had an ECG showing right bundle branch block (RBBB) and a AVR ST segment elevation. At the time of the urgent coronary angiography, it was noticed that the LMCA was totally occluded. This case has been presented in order to emphasize that peculiar changes might bring about devastating consequences as in our rare case, showing acute left main coronary artery occlusion, and ST segment elevation only in the AVR on the 12-lead ECG along with upward deflection of ST segment vector might be critical for accurate diagnosis.     

T/QRS ratio best distinguishes ventricular aneurysm from anterior myocardial infarction

OBJECTIVES: Reperfusion therapy for acute myocardial infarction (AMI) is indicated in the presence of ST elevation (STE) and ischemic symptoms. Previous MI may present with persistent STE or "left ventricular aneurysm" (LVA) morphology that mimics AMI. Hypothesis A high ratio of T amplitude to QRS amplitude best distinguishes AMI from LVA. METHODS: This was a retrospective cohort analysis. Patients with anatomical LVA by echocardiography were identified and those who presented to the ED with ischemic symptoms and STE of at least 1 mm in 2 consecutive leads and ruled out for acute left anterior descending coronary artery (LAD) occlusion were selected. Electrocardiograms (ECGs) were compared with a control group of 37 consecutive anterior AMI (aAMI) with proven acute LAD occlusion. Bundle-branch block was excluded. Various ECG measurements and ratios were compared. RESULTS: Twenty patients with LVA met the inclusion criteria. The best discriminator was T amplitude sum to QRS amplitude sum ratio V1-V4, misclassifying only 4 (6.8%) of 59 cases at a cutoff of >0.22 for AMI. For aAMI and LVA, respectively, mean (+/-95% CI) ratio of the sum of T amplitudes in V 1 to V 4 to the sum of QRS amplitude in V1-V4 was 0.54+/-0.085 and 0.16+/-0.021 (P<.00012). Thirty-five of 37 aAMI had a ratio>0.22; the false negatives (ratio<0.22) had 11.5 and 6 hours of symptoms before the ECG. Twenty of 22 LVA had a ratio相似文献   

Lead aVL on electrocardiogram: emerging as important lead in early diagnosis of myocardial infarction?

Although a diagnosis of acute myocardial infarction (AMI) that mandates emergency reperfusion therapy requires ST-segment elevation greater than 1 mm in at least 2 contiguous leads, some of the early electrocardiogram (ECG) changes of AMI can be subtle. Any ST-segment depression or T-wave inversion in lead aVL may be implicated in left anterior descending artery lesion or early reciprocal changes of inferior wall myocardial infarction, particularly when the clinical context suggests ischemia. Early recognition of reciprocal changes and serial ECG help initiate early appropriate intervention. Heightened awareness of ST segment and T-wave changes in lead aVL is of paramount importance to quickly identifying life-threatening condition.     

Primary Angioplasty in Patient with St-Segment Elevation Myocardial Infarction in the Setting of Intentional Carbon Monoxide Poisoning

Background

ST-segment elevation myocardial infarction (STEMI) due to coronary artery occlusion in the setting of acute carbon monoxide (CO) poisoning is a very rare presentation.

Objective

Our aim was to report on the use of primary angioplasty in a patient with STEMI in the setting of CO poisoning.

Case Report

A 36-year-old man with retrosternal chest pain was admitted after exposure to CO. The initial electrocardiogram (ECG) showed ST depression in I, aVL, and V3−V4 with slight ST elevation in II, III, aVF leads. Toxic carboxyhemoglobin level of 22% and troponin I of 2.19 μg/L were confirmed. After oxygen therapy the chest pain diminished, but after about 15 h it returned. The repeat ECG revealed normalization of previous ST depression with persistent ST elevation in II, III, aVF leads. The troponin I concentration was 5.94 μg/L. An echocardiogram demonstrated an apex hypokinesia involving the adjacent segments of the anterior and lateral wall. On the coronary angiogram, an acute occlusion of the distal left anterior descending coronary artery was confirmed. Primary percutaneous coronary intervention (PCI) of the infarct-related artery was performed. After PCI, the patient was symptom free and had partial ST-segment elevation resolution. The patient was discharged home after 7 days, with persistent ST-T changes and mild hypokinesia of the apex suggesting myocardial injury.

Conclusions

Patients with toxic CO exposure who have symptoms of STEMI should be carefully evaluated with serial ECG, cardiac necrosis marker measurements, and an echocardiogram. When there is evidence of myocardial injury, a wider use of coronary angiography can identify patients who could benefit from PCI.     

Errors in Emergency Physician Interpretation of ST-segment Elevation in Emergency Department Chest Pain Patients

OBJECTIVE: To determine the rate of error in emergency physician (EP) interpretation of the cause of electrocardiographic (ECG) ST-segment elevation (STE) in adult chest pain patients. METHODS: The authors conducted a retrospective ECG review of adult chest pain patients in a university hospital emergency department (ED) over a three-month period (January 1 to March 31, 1996). ST-segment elevation was determined to be present if the ST segment was elevated >/=1 mm in the limb leads and >/=2 mm in the precordial leads in at least two anatomically contiguous leads. Initial EP ECG interpretation was compared with the final interpretation by a cardiologist supported by the results of various clinical investigations. The rate of incorrect ECG diagnosis was calculated. RESULTS: Two hundred two patients had STEs. The rate of ECG STE misinterpretation was 12 of 202 (5.9%). The most frequently misdiagnosed form of STE was left ventricular aneurysm, for which two of five cases were believed to represent acute myocardial infarction (AMI). The benign early repolarization (BER) pattern was the second most frequently misinterpreted STE entity-in a total of three cases, two were initially noted to represent pericarditis and one AMI. ST-segment elevation resulting from actual AMI was initially incorrectly noted to be noninfarction in etiology in two cases, one patient with BER and the other with left ventricular hypertrophy. CONCLUSIONS: Emergency physicians show a low rate of ECG misinterpretation in the patient with chest pain and STE. The clinical consequences of this misinterpretation are minimal.     

Diagnostic and prognostic value of exercise electrocardiography for coronary artery disease

A positive exercise ECG with greater than or equal to 1.0 mm ischemic ST-segment depression, limited exercise duration, persistence of ischemic ST-segment depression past 8 minutes in the recovery period, and exertional hypotension is associated with increasing severity and extent of CAD. The sensitivity and specificity of the exercise ECG are not dependent on the prevalence of CAD in the population tested. The positive and negative predictive values of the exercise ECG are both dependent on the prevalence of CAD in the population tested. Exercise-induced ST-segment elevation greater than or equal to 1.0 mm is associated with severe myocardial ischemia, left ventricular aneurysm, left ventricular wall motion abnormalities, and coronary artery spasm in patients with variant angina. Ischemic ST-segment depression greater than or equal to 1.0 mm, exercise duration, maximal exercise heart rate, and blood pressure response to exercise are correlated with new coronary events in patients with documented CAD. Low-level exercise tests within 3 weeks of uncomplicated MI can identify patients at high risk for new cardiac events. Early post-MI patients with exercise-induced ischemic ST-segment depression greater than or equal to 1.0 mm, exercise-induced angina, an inadequate blood pressure response to exercise, or limited exercise duration during a low-level exercise test should undergo coronary angiography and be considered for possible coronary artery surgery or angioplasty. Exercise testing will also help in the medical treatment of patients with exercise-induced angina or malignant ventricular arrhythmias. An exercise test performed 6 months after MI also provides prognostic information not available from clinical evaluation.(ABSTRACT TRUNCATED AT 250 WORDS)