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Year : 2002  |  Volume : 3  |  Issue : 3  |  Page : 5 Table of Contents     

ST- Segment Elevation During Stress Test in Left Main Coronary Artery Stenosis

Director, Cardiac Catheterization Laboratory, Cardiology & Cardiovascular Surgery Department, Hamad Medical Corporation, Doha, Qatar

Date of Web Publication22-Jun-2010

Correspondence Address:
Ayman Elmenyar
Director, Cardiac Catheterization Laboratory, Cardiology & Cardiovascular Surgery Department, Hamad Medical Corporation, Doha
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Source of Support: None, Conflict of Interest: None

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How to cite this article:
Elmenyar A. ST- Segment Elevation During Stress Test in Left Main Coronary Artery Stenosis. Heart Views 2002;3:5

How to cite this URL:
Elmenyar A. ST- Segment Elevation During Stress Test in Left Main Coronary Artery Stenosis. Heart Views [serial online] 2002 [cited 2023 Sep 23];3:5. Available from: https://www.heartviews.org/text.asp?2002/3/3/5/64478

   Introduction Top

Left main coronary artery (LMCA) stenosis is associated with poor long-term prognosis without surgery [1],[2],[3] . Patients with LMCA stenosis cannot be detected on the basis of their clinical presentation alone, which may not be different from those with milder coronary artery disease (CAD), hence additional investigations are needed [4],[5],[6] . Exercise treadmill test may suggest the presence of such lesion and other serious CAD by giving a high index of suspicion [6],[7],[8],[9].

   Case presentation Top

A 48-year-old Indian male patient presented to the cardiology outpatient clinic with atypical chest pain of a few day's duration. Apart from a family history of CAD, he had no other risk factors such as smoking, diabetes or hypertension. Physical examination was not remarkable. He was referred for exercise treadmill test. On the day of ETT, the patient was stable, his BP 130/80, pulse 70/min. and resting ECG was normal [Figure 1]. At the end of stage 1, he felt tired and developed mild chest pain with ST-elevation in V2 - V4 [Figure 2]. The test was stopped and the patient was given sublingual Nitroglycerin with relief of chest pain and resolution of ST-elevation within one minute. However, almost immediately, he developed ST depression in leads II, III, AVF, V5 and V6 [Figure 3], which lasted for 5 minutes followed by complete normalization of the ECG [Figure 4]. He was admitted to the coronary care unit (CCU). Anti-ischemic therapy with aspirin, betablocker and nitrate was initiated, including subcutaneous Enoxaparin. Cardiac enzymes were normal and Troponin T-test was negative; serum cholesterol was 4.8 and triglyceride was 2.0. Echocardiogram revealed left ventricular ejection fraction of 58% with hypokinesia of the apex and inferolateral wall. A coronary angiogram revealed 80% left main coronary artery stenosis with total occlusion of the left anterior descending coronary artery, 80% lesion in the circumflex, and 60% distal RCA lesion [Figure 5]. The patient underwent urgent coronary artery bypass graft (CABG). Postoperative recovery was uneventful.

   Discussion Top

Exercise treadmill test (ETT) has been used to identify patients with coronary artery disease (CAD) as well as predict its severity and the urgency for intervention [5],[10],[11] . Patients with 3-vessel disease with significant LMCA stenosis have a 60% 4-year survival compared to a 70% 4-year survival in those without LMCA disease [12] . Good exercise performance indicates a better prognosis in patients with LMCA and/or 3-vessel disease than those with similar lesions but have poor exercise performance [11],[13] . Most of the patients with LMCA stenosis have extensive disease elsewhere in their coronary artery tree as well [14] . It is not surprising that patients with left main and 3-vessel disease have similar exercise performance but the difference in prognosis reflects the difference in mortality associated with a chance event such as plaque rupture with thrombus formation when it occurs in the left main coronary artery rather than elsewhere. The clinical and noninvasive indicators of LMCA stenosis such as crescendo angina, transient ST-depression with pain, simultaneous anterior and inferior ST-T changes during pain and fluoroscopic calcification of LMCA are well recognized but still have a low sensitivity and low predictive value to be of diagnostic value [15] . During ETT, patients with LMCA disease tend to show an earlier onset, longer duration and more widespread ST-depression than those with 3-vessel disease. However, there is no single variable that helps to distinguish LMCA from 3-vessel CAD or to predict the presence of LMCA stenosis. The predictive accuracy of ETT findings can be increased to 74% if more than one of the following variables are recognized [5] : development of downsloping ST depression, ST-depression >2mm, onset of ST changes in stage 1, persistence of ST-changes beyond 3 minutes, appearance of ST-changes in at least 3 ECG leads or exertional ST-elevation [9],[17] . Thomson and Keleman [16] found that 33% of their patients with exercise-induced hypotension had at least 75% stenosis of LMCA. Goldschlager et al [7] reported also that the duration of exercise-induced ischemia is extended longer in the recovery period in patients with LMCA stenosis. Stone et al observed that the presence of coexistent RCA disease exerted a major adverse effect on ETT performance in patients with LMCA disease and these patients had higher incidence of ventricular arrhythmia, exertional hypotension, and exertional ST elevation more than those with normal RCA [18].

   ST elevation during ETT Top

ST elevation during ETT is not a common finding and it is important to differentiate elevation occurring over or adjacent to Q waves from elevation in non-Q areas. Candell et al, reported that in patients without previous infarction and with exercise-induced ST-elevation, very severe perfusion defects were detected when the radionuclide has been injected during the crisis of Thalium stress test [19] . ST elevation during ETT on normal resting ECG represents severe transmural ischemia [Table 1] [9],[17],[20] it is very arrythmogenic and more accurate in localizing the affected vessel than ST depression [Table 2] [21],[22].

ST-elevation in non-Q areas is a very rare event. It occurs in 0.1%-0.5% of cases [23],[24] . During ETT, ST-elevation occurring purely during exercise indicates more severe lesions than when it occurs in the recovery period [25] . ST elevation on normal ECG may occur in patients with variant angina during ETT [26] . On the other hand, ST elevation in the presence of Q-waves represents wall motion abnormalities, left ventricular aneurysm, or residual viable myocardium within an infarct [27],[28] . In the CASS study, ST elevation during both exercise and recovery phase showed a significant reduction in coronary event-free survival and it was also noted that exercise-induced ST elevation when tested 2 weeks after uncomplicated myocardial infarction indicated higher morbidity and mortality [29],[30],[31] . Our patient had normal resting ECG and no major risk factors apart from his family history. The pretest probability of CAD was low. The grossly abnormal ECG changes during ETT were rather surprising. The early development of chest pain in stage 1 with accompanying ST-elevation in leads V2-V4 indicated tight proximal left system stenosis whereas the subsequent development of ST-depression in the inferolateral leads suggested concomitant significant lesions in the RCA and circumflex arteries. The ST depression was not due to reciprocal change since it occurred after resolution of ST-elevation. Coronary angiography confirmed the pathology highly suspected from the results of the ETT.

   Conclusion Top

Exercise testing might give a high index of suspicion for the presence of LMCA before angiography. ST elevation during ETT in the absence of prior infarction should be taken seriously as a clue to the presence of LMCA stenosis or its equivalent.

   References Top

1.Takaro T, Hultgren HN, Lipton MJ, Detre KM, and participants in the study groups: the VA cooperative randomized study of surgery for coronary arterial occlusive disease: II. Subgroup with significant left main lesions. Circulation 1976; 54 (Suppl 3):III-107-116.  Back to cited text no. 1      
2.European Coronary Surgery Study Group: Long-term results of prospective randomized study of coronary artery bypass surgery instable angina pectoris. Lancet 1982; 2:1173-1180.  Back to cited text no. 2      
3.Mock MB, Killip T. Effect of coronary bypass surgery on survival patterns in subsets of patients with left main coronary artery disease: report of the collaborative study in coronary artery surgery (CASS). Am J Cardiol 1981; 48:765-777.  Back to cited text no. 3      
4.Stone PH, Goldschlager N: Left main coronary artery disease: Review and appraisal. Cardiovasc Med 1979; 4:165.  Back to cited text no. 4      
5.Weiner DA, McCabe CH, Ryan TJ: Identification of patients with left main and three-vessel coronary disease with clinical and exercise test variables. Am J Cardiol 1980; 46:21-27.  Back to cited text no. 5      
6.Cheitlin MD, Davia JE, deCastro CM, Barrow EA, Andersen WT: Correlation of "critical" left coronary artery lesions with positive submaximized exercise tests in patients with chest pain. AM heart J 1975; 89:305.  Back to cited text no. 6      
7.Goldschlager N, Selzer A, Cohn K: Treadmill stress tests as indicators of presence and severity of coronary artery disease. Ann Intern Med 1976; 85:277.  Back to cited text no. 7      
8.Cohn K, Kamm B, Feteih N, Brand R, Goldschlager N: Use of treadmill score to quantify ischemic response and predict extent of coronary disease. Circulation 1979; 59:286.  Back to cited text no. 8      
9.Longhurst JC, Kraus WL: Exercise-induced ST elevation in patients without myocardial infarction. Circulation 1979; 60:616.  Back to cited text no. 9      
10.Cohn K, Kamm B, Feteih N, Brand R, Goldschlager N: Use of treadmill score to quantify ischemic response and predict extent of coronary disease. Circulation 1979; 59:286-296.  Back to cited text no. 10      
11.Raymond J, Gibbon SF, Earl F, Manuel L, Brown C, et al. Comparison of exercise performance in left main and 3 - vessel coronary artery disease. Catheterization and Cardiovascular Diagnosis 1991; 22:14 - 20.  Back to cited text no. 11      
12.Mock MB, Ringquist I, Fisher LD, David KB, Chaitman BR, Kouchoukos NT, Kaiser GC, Alderman E, Ryan TJ, Russell RO, Jr, Mullin S, Fray D, Killip T, III, Participants in the CASS: Survival of medically treated patients in the Coronary Artery Surgery Study (CASS) registry. Circulation 1982; 66:562-568.  Back to cited text no. 12      
13.Bonow RO, Kent KM, Rosing DR, Lan KKG, Lakatos E, Borer JS, Bacharach SL, Green MC, Epstein SE: Exercise-induced ischemia in mildly symptomatic patients with coronary artery disease and preserved left ventricular function: Identification of sub-groups at risk of death during medical therapy. N Engl J Med 1984; 311:1339- 1345.  Back to cited text no. 13      
14.Bulkley BH, Roberts WC: Atherosclerotic narrowing of the left main coronary artery. Necropsy analysis of 152 patients with fatal coronary heart disease and varying degrees of left main narrowing. Circulation 1976; 53:823- 828.  Back to cited text no. 14      
15.Plotnick GD, Greene HL, Carliner NH, Becker LC, and Fisher ML. Clinical indicators of left main coronary artery disease in unstable angina. Ann Intern Med 1979; 91:149- 153.  Back to cited text no. 15      
16.Thomson PD, Kelemen MH. Hypotension accompanying the onset of exertional angina. Circulation 1975; 52:28- 32.  Back to cited text no. 16      
17.Chahine RA, Raiznar AE, Ishimori T: The clinical significance of exercise-induced ST-segment elevation. Circulation 1976; 54:209.  Back to cited text no. 17      
18.Stone PH,Lafolette LE,Cohn K.Pattern of exercise treadmill test performance in patients with left main coronary artery disease:detection dependent on left dominance or coexistent dominant right coronary artery. Am Heart J 1982; 104:13-19.  Back to cited text no. 18      
19.Candell Riera J, Castell J, Rius A, Buxeda M, et al. ST segment elevation during exercise test and perfusion scintigraphy in patients without infarction. Rev Esp Cardiol 1995 Sep;48(9):600 - 605.  Back to cited text no. 19      
20.Hegge FN, Tuna N, Burchell HB. Coronary arteriographic ` findings in patients with axis shifts or ST elevation on exercise testing. Am Heart J 1973;86:603.  Back to cited text no. 20      
21.Roelli H, Tartini R, et al. The significance of ST elevation in the exercise ECG. Schweiz Med Wochenschr 1985; 11:115 (19): 644 - 650.  Back to cited text no. 21      
22.Victor FF, Susan Q. ECG responses in: Handbook of exercise testing. Little Brown of Boston 1992; (Chap.15); 108 - 109.  Back to cited text no. 22      
23.Lobbe L, Douard H, Espil G, Chevalier L, et al. Significance of exercise induced ST elevation in patient without a history of previous myocardial infarction. Arch Mal Coeur Vaisis 1999; 92 (10): 1287 - 1294.  Back to cited text no. 23      
24.Ekmekei A., Toyoshima H. Et al. Angina pectoris. IV. Clinical and experimental difference between ischemia with ST elevation and ischemia with ST depression. Am J. Cardiol 1961;7:412.  Back to cited text no. 24      
25.Irace L, Aquino D, Scialdyne , et al. ST elevation during ergometric test: Correlation with coronary angiography. Minerva Cardiolioangiol 1993 May; 41(5): 177 - 185.  Back to cited text no. 25      
26.Mark DB, Hlatky MA, Lee KL, Harrel FE, et al. Localizing coronary artery obstructions with the exercise treadmill test. Ann Intern Med 1987 January; 106(1): 53 - 55.  Back to cited text no. 26      
27.Detry JR, Mengeot P, Rousseau MF, Cosyns J, Ponlot R, Brasseur LA: Maximal exercise testing in patients with spontaneous angina pectoris associated with transient ST segment elevation: risks and electrocardiographic findings. Br Heart J 1975; 37: 897.  Back to cited text no. 27      
28.Manvi KN, Ellestad MH: Elevated ST segments with exercise in ventricular aneurysm. J Electrocardiol 1972; 5: 317.  Back to cited text no. 28      
29.The Principal Investigators of CASS and their Associates: The National Heart, Lung, and Blood Institute Coronary Artery Surgery Study (CASS). Circulation 63(Suppl III): I I-1, 1981.  Back to cited text no. 29      
30.Hossack KF, Sivarjian ES, Almes MJ, Belanger R, Green B, Bruce RA: Prognostic alue of ST elevation during low level treadmill testing early after myocardial infarction. Am J Cardiol 1982; 49:932.  Back to cited text no. 30      
31.Haines DE, Beller BA, Watson DD, Kaiser DL, Sayre SL, Gibson RS: Exercise-induced ST segment elevation two weeks after uncomplicated myocardial infarction: contributing factors and prognostic significance. J Am Coll Cardiol 1987; 9:996.  Back to cited text no. 31      


  [Figure 1], [Figure 2], [Figure 3], [Figure 4], [Figure 5]

  [Table 1], [Table 2]


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