Exercise-induced ST-segment Elevation Research Articles

Exercise-Induced ST Changes in aVR, V5 and V1 in Differentiation between Single and Multi-Vessel Coronary Artery Disease

Background: Angina occurs when there is regional myocardial ischemia causedby inadequate coronary perfusion and is usually but not alwaysinduced by increases in myocardial oxygen requirements. Objective: The aim of this work was to study the significance of ST changes in aVR, V5, V1 during exercise ECG for diagnosis of single -or multi-vessel coronary artery disease. Patients and methods: This study had been carried out in the cardiology department, Zagazig University and National Hear Institute during the period from January 2005 to January 2007. This study included 56 patients (40 male +16 female) with chronic stable angina. Results: Comparison was done among groups regarding demographic data, resting ECG data, echocardiographic findings and there were no statistical significant difference among groups. Single vessel disease: LAD: - the ability of the test to detect left anterior descending (LAD) lesion as a single vessel disease has high specificity 87.5%, high +ve predictive value 96%, but low sensitivity 50%. Left circumflex (LCx): the sensitivity of the test to detect LCx lesion as a single vessel disease was 53.4%, specificity 60%, but with low +ve predictive value 44%. RCA: as regard RCA lesion the test has low sensitivity, specificity positive and negative predictive values. Conclusion: The concomitant appearance of exercise-induced ST-segment elevation in lead V1 and in lead aVR with simultaneous ST-segment depression in lead V5, or the isolated appearance of ST-segment elevation in lead V1 mostly detects single-vessel disease and correlates strongly with significant narrowing of the LAD coronary artery as single-vessel disease, or with significant stenosis of the LAD and LCx coronary arteries as double-vessel disease.

Prevalence and Associated Clinical Characteristics of Exercise-Induced ST-Segment Elevation in Lead aVR

BackgroundExercise-induced ST-segment elevation (STE) in lead aVR may be an important indicator of prognostically important coronary artery disease (CAD). However, the prevalence and associated clinical features of exercise-induced STE in lead aVR among consecutive patients referred for exercise stress electrocardiography (ExECG) is unknown.MethodsAll consecutive patients receiving a Bruce protocol ExECG for the diagnosis of CAD at a tertiary care academic center were included over a two-year period. Clinical characteristics, including results of coronary angiography, were compared between patients with and without exercise-induced STE in lead aVR.ResultsAmong 2227 patients undergoing ExECG, exercise-induced STE ≥1.0mm in lead aVR occurred in 3.4% of patients. Patients with STE in lead aVR had significantly lower Duke Treadmill Scores (DTS) (-0.5 vs. 7.0, p<0.01) and a higher frequency of positive test results (60.2% vs. 7.3%, p<0.01). Furthermore, patients with STE in lead aVR were more likely to undergo subsequent cardiac catheterization than those without STE in lead aVR (p<0.01, odds ratio = 4.2).ConclusionsAmong patients referred for ExECG for suspected CAD, exercise-induced STE in lead aVR was associated with a higher risk DTS, an increased likelihood of a positive ExECG, and referral for subsequent coronary angiography. These results suggest that exercise-induced STE in lead aVR may represent a useful ECG feature among patients undergoing ExECG in the risk stratification of patients.

PREVALENCE OF EXERCISE INDUCED ST-SEGMENT ELEVATION IN LEAD AVR

The exercise stress test (EST) is a valuable tool for the detection of coronary artery disease (CAD). Preliminary studies suggest that exercise induced ST-segment elevation (STE) in lead aVR may be an important indicator of prognostically important CAD. However, studies have been limited by their

Asymptomatic ST segment elevation in the recovery phase of the exercise stress test due to slow coronary flow.

Exercise-induced ST segment elevation without Q wave formation is rarely observed. Frequent causes are significant coronary stenosis, myocardial bridge and coronary vasospasm. Both exercise-induced ST segment elevation due to slow coronary flow and ST segment elevation in the recovery phase of the exercise stress test are very rare. We present a 49-year-old man with asymptomatic inferolateral ST segment elevation in the recovery phase of the exercise stress test due to slow coronary flow, which has not been reported previously. The learning points of the present paper are as follows: a) although significant coronary stenosis, myocardial bridge and coronary vasospasm are frequent causes of exercise-induced ST segment elevation, slow coronary flow might also cause it; b) one should keep in mind that ST segment elevation might also occur in the recovery phase; and c) ST segment elevation might be asymptomatic, as in the present case.

Exercise-Induced ST-Segment Elevation in ECG Lead aVR Is a Useful Indicator of Significant Left Main or Ostial LAD Coronary Artery Stenosis

The authors tested the hypothesis that exercise treadmill testing (ETT)-induced ST-segment elevation (STE) in electrocardiographic lead aVR is an important indicator of significant left main coronary artery (LMCA) or ostial left anterior descending coronary artery (LAD) stenosis. Although STE in lead aVR is an indicator of LMCA or very proximal LAD occlusion in acute coronary syndromes, its predictive power in the setting of ETT is uncertain. Rest and stress electrocardiograms, clinical and stress test parameters, and single photon-emission computed tomographic myocardial perfusion imaging (MPI) data, when available, were obtained in 454 subjects (378 with MPI) who underwent cardiac catheterization and standard Bruce ETT ≤ 6 months before catheterization. Patients were selected for LMCA or ostial LAD disease (≥ 50% stenosis) with or without other coronary artery disease (CAD), CAD (≥ 70% stenosis) without significant LMCA or ostial LAD, or no significant CAD. Univariate followed by multivariate logistic regression analyses of clinical, electrocardiographic, stress test, and single photon-emission computed tomographic MPI variables were used to identify significant correlates of LMCA or ostial LAD stenosis. Bayesian analysis of the data also was performed. LMCA (n = 38) or ostial LAD (n = 42) stenosis occurred in 75 patients (5 patients had both). The remainder had CAD without LMCA or ostial LAD stenosis (n = 276) or no CAD (n = 103). In multivariate analysis, the strongest predictor was stress-induced STE in lead aVR (p < 0.0001, area under the curve 0.82). Both left ventricular ejection fraction (after stress) and percent reversible LAD ischemia on single photon-emission computed tomographic MPI also contributed significantly in multivariate analysis (p < 0.005 and p < 0.05, respectively, areas under the curve 0.60 and 0.64, respectively). Although additional electrocardiographic, stress test, and MPI variables were significant univariate predictors, none was statistically significant in multivariate analysis. At 1-mm STE in lead aVR, sensitivity for LMCA or ostial LAD stenosis was 75%, specificity was 81%, overall predictive accuracy was 80%, and post-test probability increased nearly 3 times from 17% to 45%. Stress (ETT)-induced STE in lead aVR is an important indicator of significant LMCA or ostial LAD stenosis and should not be ignored.

Exercise-induced ST-segment elevation

Exercise-induced ST-segment elevation in patients without previous myocardial infarction is a relatively uncommon finding. When it does occur, it may be associated with significant coronary artery disease or coronary vasospasm. Here we describe a case of exercise-induced ST-segment elevation in both anterior and inferior leads in a patient with a critical stenosis on a wrapped left anterior descending artery, successfully treated with transluminal coronary artery angioplasty.

Acute myocardial infarction with significant left main coronary artery stenosis, significant 3-vessel coronary artery disease and elevated troponin-I at admission

Exercise-induced ST-segment elevation in lead aVR accompanied by ST-segment elevation in lead V1 might be a specific finding of left main coronary artery (LMCA) stenosis. Lead aVR and lead v1 ST segment elevation has been reported, during an attack of chest pain, in patients with LMCA disease with ST segment depression in leads V3, V4 and V5 (with maximal depression in V4). ST-segment elevation in lead aVR in patients with angina at rest can be related to transmural ischemia of the basal part of the interventricular septum, frequently due to LMCA or multivessel coronary disease too. 3-vessel coronary artery disease (CAD) and LMCA disease show a frequent combination of leads with abnormal ST segments during chest pain with ST-segment depression in leads I II V4-V6, and ST-segment elevation in lead aVR. When ST-segment status in lead aVR combines with troponin T, ST-segment elevation in lead aVR and positive troponin T on admission are useful predictors of LMCA or 3-vessel CAD. We present a case of acute myocardial infarction with significant left main coronary artery stenosis, significant 3-vessel coronary artery disease and elevated troponin I at admission in an 83-year-old Italian woman. Also this case focuses attention on the importance of the recognition of the patterns suspected for LMCA and/or 3-vessel coronary disease.

Exercise-induced ST-segment elevation during treadmill exercise testing

The exercise electrocardiogram is a commonly used non-invasive and inexpensive method for detection of electrocardiogram (ECG) changes secondary to myocardial ischemia. It has been reported that in patients with a first myocardial infarction and without residual ischemia, exercise-induced ST-segment elevation in Q leads is related to a more damaged coronary microcirculation and to less viable myocardium. Exercise-induced ST-segment elevation is a rare phenomenon in patients without prior myocardial infarction. When occurring purely during exercise, coronary lesions are frequent and often severe, and on the other hand ST-segment elevation of the recovery phase is frequently associated with normal arteries or less severe lesions. We present a case of exercise-induced ST-segment elevation in a 51-year-old Italian man. Coronary angiography revealed a significant left anterior descending coronary artery stenosis, a significant circumflex coronary artery stenosis, a significant first obtuse marginal coronary artery stenosis and a significant second obtuse marginal coronary artery stenosis. Percutaneous transluminal coronary angioplasty with implantation of stents was successfully performed. Also this case is illustrative of the rare phenomenon of exercise-induced ST-segment elevation.

Exercise‐Induced ST‐Segment Elevation in Patients with a Recent Acute Myocardial Infarction Treated by Primary Percutaneous Coronary Intervention

To get insight in the mechanism of exercise-induced ST-segment elevation (STE) in patients with Q/QS waves at the electrocardiogram (ECG). We performed exercise stress test in 13 patients with anterior acute myocardial infarction treated by successful primary percutaneous coronary intervention (PCI). Compared to rest, an additional STE > or = 1 mm in one or more precordial ECG leads during exercise occurred in nine patients (69%), in the absence of symptoms. In acute myocardial infarction (MI) patients, treated by primary PCI and showing optimal coronary blood flow restoration at angiography, STE can still be induced by exercise in Q/QS wave ECG leads. This finding lends further support to the theory that exercise-induced STE in this clinical context is unlikely to represent by itself transient myocardial ischemia or viability.

Exercise-induced ST-segment elevation in leads aVR and V 1 for the prediction of left main disease

Background This study investigated the value of exercise-induced ST-segment elevation in lead aVR with or without concomitant ST-segment elevation in lead V 1 for detection of left main (LM) coronary artery disease in patients with Duke treadmill score ≤− 11. Methods One hundred and four patients with Duke treadmill score ≤− 11 were retrospectively screened for presence of ST-segment elevation in lead aVR and lead V 1. Results Twenty-six out of 65 patients with ST-segment elevation in lead aVR and 24 out 38 patients with ST-segment elevation in lead aVR with concomitant ST-segment elevation in lead V 1 were found to have LM disease. Exercise-induced ST-segment elevation in lead aVR had a sensitivity of 92.9% and a specificity of 48.6% and ST-segment elevation in lead aVR accompanied by ST-segment elevation in lead V 1 had a sensitivity of 85.7% and a specificity of 81.6% in predicting LM disease. Conclusions This study shows that the observation of exercise-induced ST-segment elevation in lead aVR is a sensitive, but not a specific, electrocardiographic finding of significant LM coronary artery disease. However, exercise-induced ST-segment elevation in lead aVR accompanied by ST-segment elevation in lead V 1 might be not only a sensitive but also a specific finding of LM stenosis in these patients.

Relationship Between the Exercise-induced ST-segment Elevation in Infarct-related Leads and Parameters of Cardiopulmonary Exercise Test on Acute Myocardial Infarction

Purpose: Exercise-induced ST-segment elevation in infarct-related leads is often seen in the treadmill exercise test of patients with myocardial infarction (MI). The purpose of this study is to evaluate the relationship between this phenomenon and parameters of cardiopulmonary exercise test during cardiac rehabilitation on acute MI.

A New Application of the ST-HR Loop to Evaluate the Exercise-Induced Reversible Ischemia in Healed Anterior Wall Myocardial Infarction

Exercise-induced ST-segment elevation in infarct-related leads is often seen on the treadmill exercise electrocardiogram of patients with anterior wall myocardial infarction. However, the cause of this phenomenon is still a matter of controversy. The purpose of this study was to evaluate the relation between the direction of ST-segment-heart rate (ST-HR) loop rotation and reversible myocardial ischemia in the infarct-related area. A total of 58 patients were enrolled in this study. They had healed anterior wall myocardial infarctions with single-vessel coronary artery disease and exercise-induced ST-segment elevations in the infarct-related leads, as observed on treadmill exercise electrocardiograms. All patients underwent treadmill exercise electrocardiography and dobutamine stress echocardiography at discharge. The direction of rotation of the ST-HR loop constructed from the treadmill exercise electrocardiogram and the dobutamine stress echocardiographic findings in the infarct-related area were compared. Counterclockwise rotation was seen in 26 of 58 patients. Compared with clockwise rotation, patients with counterclockwise rotation had significantly more viable myocardium (92% vs 69%, p = 0.04) and presence of reversible myocardial ischemia (58% vs 6%, p < 0.01). On the basis of the counterclockwise rotation findings, the diagnostic value of the presence of reversible myocardial ischemia was calculated. The sensitivity, specificity, and accuracy was 88%, 73%, and 77%, respectively. Counterclockwise rotation of ST-HR loops was strongly related to reversible myocardial ischemia in the infarct-related area. In conclusion, our results have shown that analysis of ST-HR loops may be useful in evaluating the cause of exercise-induced ST-segment elevation in infarct-related leads.

Clinical Characteristics of Patients With Exercise-Induced ST-Segment Elevation Without Prior Myocardial Infarction

Exercise-induced ST-segment elevation is a relatively uncommon problem and occurs more frequently in patients who have had a myocardial infarction. Data is limited on the characteristics of Taiwanese patients without prior myocardial infarction who develop exercise-induced ST-segment elevation. Exercise-induced ST-segment elevation developed in 9 of 6,147 consecutive patients without myocardial infarction who underwent treadmill exercise testing at out institution over a 4-year period. The clinical and angiographic characteristics of these patients were studied. Angiographically normal coronary arteries with coronary vasospasm were found in 5 patients, hemodynamically significant coronary stenosis was found in 3 patients, and coexisting spasm in angiographically normal coronary arteries combined with hemodynamically significant coronary stenosis in the different vessel was found in 1 patient. During a median follow-up of 71 months, 2 patients with coronary vasospasm developed recurrent angina after self-discontinuation of calcium antagonists and 2 patients (1 with coronary vasospasm and 1 with hemodynamically significant coronary stenosis) died of cardiac causes before arrival at the emergency department. Coronary vasospasm was a more common underlying pathology of exercise-induced ST-segment elevation in this Taiwanese cohort. Coronary angiography +/- intracoronary ergonovine provocation testing is necessary in these patients to identify the underlying pathology and appropriate treatment.

Significance of exercise-induced ST segment elevation in Q leads in patients with a recent myocardial infarction and an open infarct-related artery: Analysis with angiography, intracoronary myocardial contrast echocardiography and cardiac magnetic resonance

Aims The significance of exercise-induced ST segment elevation in Q leads in patients with a recent myocardial infarction and without significant residual stenosis in the infarct-related artery has not been defined. We aimed to elucidate the role of myocardial perfusion and viability in this scenario. Methods and Results Sixty-six patients with a first myocardial infarction, single-vessel disease and an open artery were studied. Myocardial perfusion was assessed with angiographic blush, intracoronary myocardial contrast echocardiography and magnetic resonance. Myocardial viability was quantified by means of magnetic resonance (transmural extent of necrosis). Exercise-induced ST elevation in Q leads was observed only in 13 cases (20%); 53 patients (80%) did not show this finding. The group with ST elevation had fewer cases with normal perfusion: Blush 3 (15% vs. 74%, p=0.001), myocardial contrast echocardiography score >0.75 (8% vs. 81%, p=0.001) and magnetic resonance score >0.75 (31% vs. 68%, p=0.03). Similarly, myocardial viability (necrosis <50%) was less frequent in patients with ST elevation (8% vs. 72%, p=0.001). Conclusion In patients with a first myocardial infarction and without residual ischemia, exercise-induced ST segment elevation in Q leads is an uncommon finding and it is related to a more damaged coronary microcirculation and to less viable myocardium.

Significance of exercise-induced ST changes in leads aVR, V5, and V1. Discrimination of patients with single- or multivessel coronary artery disease.

It is known that exercise-induced ST-segment elevation in lead V1 (V1-E) detects left anterior descending (LAD) stenosis. It was also postulated that ST elevation in aVR and simultaneous ST depression in V5 (aVR-E + V5-D) is a marker of ischemia due to significant stenosis of the LAD in patients with single-vessel disease. This study was undertaken to investigate the significance of the concomitant appearance of both electrocardiographic (ECG) ischemic markers, and of each of them alone during exercise, to detect either LAD stenosis as single-vessel coronary artery disease (CAD), or multivessel CAD involving LAD stenosis. A total of 196 consecutive patients (152 men and 44 women, mean age 54 +/- 7 years) with at least one of these ECG markers, who underwent treadmill exercise testing with the Bruce protocol and coronary arteriography, were studied. Patients were divided into three groups. In Group A (83 patients with V1-E + aVR-E & V5-D), 93% of patients with single-vessel disease had significant LAD stenosis (p<0.001), whereas 75% of patients with double-vessel disease had significant stenoses of the LAD and the left circumflex (LCx) coronary arteries (p<0.01). In Group B (97 patients with aVR-E & V5-D but without V1-E), 43% of patients with single-vessel disease had significant LAD stenosis (p<0.08), whereas 85% of patients with double-vessel disease had significant stenoses of the LAD and the right coronary artery (RCA) (p<0.01). In Group C (16 patients with only V1-E), 60% of patients with single-vessel disease had significant LAD stenosis (p<0.05), whereas 75% of patients with double-vessel disease had significant LAD and LCx stenoses (p<0.05). The concomitant appearance of exercise-induced ST elevation in lead V1, ST elevation in lead aVR, and ST depression in lead V5, as well as the isolated appearance of ST elevation in lead V1 detect significant LAD stenosis as single-vessel disease, or significant stenoses of LAD and LCx arteries in patients with double-vessel disease, whereas the appearance of ST elevation in aVR & ST depression in V5 but without ST elevation in V1 correlates strongly with significant LAD and RCA stenoses and usually indicates double-vessel disease.

Utility of immediate exercise treadmill testing in patients taking beta blockers or calcium channel blockers

echocardiography for diagnosis of viable myocardium. Am J Cardiol 1995;75: 505–507. 8. Margonato A, Ballarotto C, Bonetti F, Cappelletti A, Sciammarella M, Cianflone D, Chierchia SL. Assessment of residual tissue viability by exercise testing in recent myocardial infarction: comparison of the electrocardiogram and myocardial perfusion scintigraphy. J Am Coll Cardiol 1992;19:948–952. 9. Margonato A, Chierchia SL, Xuereb RG, Xuereb M, Fragasso G, Cappelletti A, Landoni C, Lucignani G, Fazio F. Specificity and sensitivity of exerciseinduced ST segment elevation for detection of residual viability: comparison with fluorodeoxyglucose and PET. J Am Coll Cardiol 1995;25:1032–1038. 10. Schneider C, Voth E, Baer F, Horst M, Wagner R, Sechtem U. QT dispersion is determined by the extent of viable myocardium in patients with chronic Q-wave myocardial infarction. Circulation 1997;96:3913–3920. 11. Al Mohammad A, Mahy IR, Buckley A, Cargill RI, Norton MY, Welch AE, Walton S. Does the presence of hibernating myocardium in patients with impaired left ventricular contraction affect QT dispersion? Am Heart J 2001;141:944–948. 12. Bertella M, Scalise F, Lanzone A, Eriano G, Valentini R. Exercise standards (letter). Circulation 1995;92:3579–3580. 13. Ellestad MH. Stress Testing Principles and Practice. Philadelphia: FA Davis, 1986 256–259. 14. Lewis P, Nunan T, Dynes A, Maisey M. The use of low-dose intravenous insulin in clinical myocardial F-18 FDG PET scanning. Clin Nucl Med 1996;21:15–18. 15. Dodge HT, Sandler H, Ballew DW, Lord JD Jr. The use of biplane angiocardiography for the measurement of left ventricular volume in man. Am Heart J 1960;60:762–766. 16. Yu PNG, Soffer A. Studies of electrocardiographic changes during exercise (modified double two-step test). Circulation 1952;6:183–192. 17. Elhendy A, Geleijnse A, Salustri A, van Domburg RT, Cornel JH, Arnese M, Roelandt JRTC, Fioretti PM. T wave normalization during dobutamine stress testing in patients with non-Q wave myocardial infarction. A marker of myocardial ischemia? Eur Heart J 1996;17:526–531. 18. Mezlis NE, Parthenakis F, Kanakaraki M, Marketou M, Mavrakis H, Vardas PE. Dobutamine vs exercise-induced ST segment elevation early after Q wave myocardial infarction. Eur Heart J 2000;21:814–822. 19. Marwick TH. ST-segment elevation after myocardial infarction: what does it mean and when is it useful? Am Heart J 1999;137:1002–1003. 20. Bodi V, Sanchis J, Llacer A, Insa L, Chorro FJ, Lopez-Merino V. ST-segment elevation on Q leads at rest and during exercise: relation with myocardial viability and left ventricular remodelling within the first 6 months after infarction. Am Heart J 1999;137:1107–1115.

ST-segment elevation on Q-leads during exercise in patients with ST-segment elevation at rest after myocardial infarction

Introduction: ST-segment elevation on Q-leads after an acute myocardial infarction is related to a greater infarct size. The meaning of a further exercise-induced ST-segment elevation in these patients has not been analyzed. Method: Thirty-six patients with ST-segment elevation on Q-leads were studied after a first acute myocardial infarction. Exercise testing and cardiac catheterization were performed at the first week. Left ventricular volumes (ml/m 2); the extent of abnormal wall motion (AWM: chords); contractile reserve (AWM improvement with low dose dobutamine) and coronary patency in the culprit artery were analyzed. Cardiac catheterization was repeated at the sixth month in 20 patients; systolic recovery (AWM improvement), left ventricular volumes and coronary patency were again evaluated. Results: Patients with exercise-induced ST-segment elevation in two or more Q-leads ( n=21) showed lesser contractile reserve (6±6 vs. 12±7 chords, P=0.01) than patients without exercise-induced ST-segment elevation ( n=13). AWM ( F=8.1) and absence of exercise-induced ST-segment elevation ( F=9.5; positive predictive value: 80%; negative predictive value: 68%) were the only independent predictors of contractile reserve. Nevertheless, this electrocardiographic sign was not related to left ventricular volumes, coronary patency or systolic function and it did not predicted late systolic recovery. Conclusions: In patients with baseline ST-segment elevation on Q-leads an exercise-induced ST-segment elevation is independently related to a lesser contractile reserve but not to the evolution of volumes or regional dysfunction during the first 6 months post-infarction. Therefore, the clinical value of this sign seems to be limited to the non-invasive detection of myocardial viability during the early post-infarction phase.

Dobutamine- vs exercise-induced ST segment elevation early after Q wave myocardial infarction. Prediction of functional recovery after revascularization.

The association between stress-induced ST elevation and functional recovery following revascularization after myocardial infarction remains unclear. We assessed the relative accuracy of dobutamine- and exercise-induced ST elevation in Q wave leads in predicting functional recovery following revascularization, and we investigated the relationship of ST elevation to different wall motion responses to dobutamine. Thirty-nine patients underwent dobutamine stress echo and exercise test 8+/-2 days after Q wave myocardial infarction. All patients underwent angiography and subsequent revascularization. Follow-up echocardiograms were obtained 7+/-4 weeks after revascularization. Functional recovery was assessed by the difference between the baseline and the follow-up asynergy index. Nineteen patients (48%) developed dobutamine- and exercise-induced ST elevation. There was significant agreement between the tests (k=0.58, P<0.001). We found a significant correlation between dobutamine and exercise-induced ST elevation with functional recovery following revascularization (r=0. 45, P<0.005 and r=0.7, P<0.001, respectively). The parameters with the highest predictive value for functional recovery were: (a) the biphasic response during dobutamine infusion, (b) the development of ST elevation in both tests, and (c) the development of exercise-induced ST elevation in more than three leads. There is a strong association between dobutamine- and exercise-induced ST elevation with functional recovery following revascularization. Exercise-induced ST elevation in more than three leads and a biphasic response during dobutamine infusion accurately predict functional recovery.

Diagnostic Value of Exercise-Induced ST-Segment Elevation in Q-Wave Leads. After Recent Myocardial Infarction

Background: Exercise-induced ST-segment elevation in an infarct territory with abnormal Q waves is a known marker for more severe left ventricular wall-motion abnormalities. However, it is reported, that exercise-induced ST-segment elevation in infarct leads may indicate residual viability in the intarctregion. The aim of the study was to test whether exercise-induced ST-segment elevation is related to left ventricular (LV) dysfunction or to persistent viability in patients with previous myocardial infarction (MI). Methods: 145 consecutive patients (119 men, 26 women, age 58 ± 11 years) 2–3 weeks after Q-wave Ml but without ST elevation at rest ECG were enrolled in the study. All patients underwent a target heart rate or symptom-limited exercise testing (ET) with Bruce protocol. Exercise-induced ST-segment elevation < 1 mm above the baseline ST segment level (80 ms after J point) in more than 1 ECG lead with Q wave was considered to be significant. Patients were divided in two groups according to ET results: group I, 25 patients with significant exercise-induced ST-segment elevation and group II, 120 patients without exercise-induced ST-segment elevation. All patients underwent rest ECHO and low dose dobutamine stress echo (LOSE) within 7 days after ET. LV function was estimated using ejection fraction (EF). Results: More severe LV dysfunction was observed in patients from group 1 (EF 31 ± 8.16% vs EF 45 ± 10.3%). Myocardial viability (defined as an improvement of regional systolic wall thickening in the regions with resting regional wall-motion abnormalities during LOSE 5 to 15 g/kg/min was recognized in 8 patients (32%) in group I and 31 patients (25.8%) in group II. There was no relation between exercise-induced ST-segment elevation and myocardial viability (chi-square test: 2,809; NS). Conclusions: Exercise-induced ST-segment elevation in most cases is associated with left ventricular dysfunction. Patients with exercise-induced ST-segment elevation have a lower EF than those without and greater severity of resting wall-motion abnormalities. Our results suggest that exercise-induced ST-segment elevation is not related to residual myocardial viability.

Comparative localization of myocardial ischemia by exercise electrocardiography and myocardial perfusion SPECT

Background. Prior angiographic study has shown that the patterns of ST-segment depression during exercise do not provide localizing information of the responsible coronary lesion. However, little is known regarding the ability of exercise-induced ST segment displacement to localize myocardial perfusion defects. Methods and Results. We studied 552 consecutive patients without prior myocardial infarction who had reversible perfusion defect in one vascular territory on rest 201TI/exercise 99mTc-labeled sestamibi dual-isotope myocardial perfusion single photon emission computed tomography (SPECT) and ischemic ST depression or elevation during exercise. Of these, 192 patients had angiographically documented coronary artery disease (CAD). Two hundred thirty-two patients had maximal ST depression in anterior leads, 247 patients had maximal ST depression in inferior leads, and 45 patients had similar maximal ST depression in both anterior and inferior leads. Twenty-eight (5%) patients had ST elevation with absent Q waves. In patients with maximal ST depression in anterior leads, perfusion defects were found in the territory of the left anterior descending coronary artery (LAD) in 30%, in the territory of the right coronary artery (RCA) in 52%, and in the territory of the left circumflex coronary artery (LCX) in 18%. In patients with maximal ST depression in inferior leads, perfusion defects were found in RCA territory in 44%, in the LAD territory in 42%, and in the LCX territory in 14%. Compared with exercise ST depression, the less common finding of ST elevation did provide accurate localization of perfusion defects. When ST elevation was greatest in the anterior leads, 96% of patients had LAD territory defects. When ST elevation was most prominent in the inferior leads, 100% patients had RCA territory defects. Data of coronary angiograms demonstrated that myocardial perfusion SPECT correctly identified the most stenotic coronary disease for LAD (94%), LCX (72%), and RCA (75%). Conclusions. The findings of this study indicate that the site of maximal ST-segment depression does not identify the localization of myocardial perfusion defects. However, the less common finding of exercise-induced ST-segment elevation does predict localization of myocardial ischemia.