Post-infarction exercise testing in patients under 55 years. Relation between ischaemic abnormalities and the extent of coronary artery disease.

Previous studies have suggested that the early post-infarction exercise test is useful in predicting the extent of coronary artery disease. The results of a heart rate limited exercise test three weeks after infarction and a symptom limited exercise test six weeks after infarction obtained by both standard lead electrocardiograms and 16 lead precordial maps were compared in 100 consecutive survivors of acute myocardial infarction under 55 years of age. Exercise tests were defined as being positive on the basis of angina, ST segment depression greater than or equal to 1 mm in any electrocardiogram lead, or exertional hypotension. Multivessel disease, that is two or three vessel disease, was present in 60 patients, and three vessel disease in 22 patients. The sensitivity, specificity, and predictive value for multivessel disease of the three week test were 38%, 83%, and 76% respectively; and results for the six week test were 55%, 75%, and 77% respectively. Only 32% of patients with three vessel disease were identified at the three week test, and 59% at the six week test. Significantly more patients with multivessel and three vessel disease were identified by the symptom limited six week test. Precordial mapping offered no advantages over the standard 12 lead electrocardiogram in either the identification of patients with multivessel disease or the prediction of the distribution of coronary artery disease. Angina pectoris during the exercise test at six weeks was the single most useful predictor of multivessel disease. Multivessel disease was found in 27 (87%) of the 31 patients with angina with or without ST depression during the test at six weeks compared with 33 (48%) of the 69 patients who did not have angina during the test at six weeks. Exercise testing in the early post-infarction period in patients under 55 years of age is of limited value in predicting the extent of coronary artery disease. It is, therefore, unreasonable to use such exercise tests to select patients for coronary arteriography after myocardial infarction. None the less angina pectoris occurring during a symptom limited exercise test six weeks after infarction is a strong predictor of multivessel disease, and coronary arteriography is recommended in these patients.     

Significance of exercise induced ST elevation in patient without a history of previous myocardial infarct

Between 1980 and 1995, we observed twenty-five patients (22 males, 3 females) at the mean age of 50.6 +/- 13 years, without previous myocardial infarction who presented exercise induced ST elevation on a bicycle stress test. METHODS: Significant ST elevation was defined as a > or = 1 mm change present in > or = 1 lead measured 0.08 sec after the J point and in 3 consecutive beats. All patients have undergone coronary angiography in the days following the exercise test. RESULTS: Most of patients (56%) presented a history of typical angina that was either purely exertional (8 pts) or also occurred at rest (6 pts). Others (36%) had non typical angina or no angina (8%); 78% of pts were smokers. Sixteen patients (group I) had ST elevation during exercise (exercise duration: 7.6 +/- 4 min; peak heart rate: 135.5 +/- 29 batt/min; ST = 3.5 +/- 1.5 mm) and nine (group II) during the recovery phase (exercise duration 16.3 +/- 1.6 min; p < 0.05; peak heart rate 168 +/- 22 batt/min; p < 0.05; ST: 5.8 +/- 3 mm; p < 0.05). In group I, 1 patient had no vessel disease, 12 had one vessel disease, 3 had multivessel disease with 6 cases of hypersevere coronary stenose (> 90%). In group II, 4 patients had normal coronary arteries, there was one vessel coronary artery disease in 4 patients and multivessel in one subject, without hypersevere coronary stenosis. Correlation between anatomic location of stenosis and electrocardiographic ST elevation was excellent, particularly in case of single vessel disease (100%). All patients underwent one or more new exercise tests after therapeutic intervention (surgery n = 3; angioplasty n = 7; medical treatment n = 15), only 2 patients had persistent exercise induced ST elevation. During follow-up (5 +/- 3 years), 3 patients died (2 cardiac deaths) and 3 had recurrent angina controlled by new treatment. CONCLUSION: Exercise-induced ST elevation is a rare phenomenon in patients without prior myocardial infarction. When occurring purely during exercise, coronary lesions are frequent and often servere, in the other hand ST elevation of the recovery phase is frequently associate with normal arteries or less severe lesions. In most cases, revascularisation or medical therapy can abolish clinical and electrocardiographic abnormalities.     

Post-infarction exercise testing in patients under 55 years. Relation between ischaemic abnormalities and the extent of coronary artery disease

Previous studies have suggested that the early post-infarction exercise test is useful in predicting the extent of coronary artery disease. The results of a heart rate limited exercise test three weeks after infarction and a symptom limited exercise test six weeks after infarction obtained by both standard lead electrocardiograms and 16 lead precordial maps were compared in 100 consecutive survivors of acute myocardial infarction under 55 years of age. Exercise tests were defined as being positive on the basis of angina, ST segment depression greater than or equal to 1 mm in any electrocardiogram lead, or exertional hypotension. Multivessel disease, that is two or three vessel disease, was present in 60 patients, and three vessel disease in 22 patients. The sensitivity, specificity, and predictive value for multivessel disease of the three week test were 38%, 83%, and 76% respectively; and results for the six week test were 55%, 75%, and 77% respectively. Only 32% of patients with three vessel disease were identified at the three week test, and 59% at the six week test. Significantly more patients with multivessel and three vessel disease were identified by the symptom limited six week test. Precordial mapping offered no advantages over the standard 12 lead electrocardiogram in either the identification of patients with multivessel disease or the prediction of the distribution of coronary artery disease. Angina pectoris during the exercise test at six weeks was the single most useful predictor of multivessel disease. Multivessel disease was found in 27 (87%) of the 31 patients with angina with or without ST depression during the test at six weeks compared with 33 (48%) of the 69 patients who did not have angina during the test at six weeks. Exercise testing in the early post-infarction period in patients under 55 years of age is of limited value in predicting the extent of coronary artery disease. It is, therefore, unreasonable to use such exercise tests to select patients for coronary arteriography after myocardial infarction. None the less angina pectoris occurring during a symptom limited exercise test six weeks after infarction is a strong predictor of multivessel disease, and coronary arteriography is recommended in these patients.     

Is there an indication for coronary angiography in patients under 60 years of age with no or minimal angina pectoris after a first myocardial infarction?

Coronary angiography and exercise stress tests were performed in 91 consecutive patients under 60 years of age having either no or only mild angina pectoris with or without medication after a first myocardial infarction. Nine (10%) patients had angiographic high risk coronary artery disease defined as three vessel disease, left main stenosis, or proximal stenosis of the left anterior descending artery. Eighteen patients had a positive electrocardiographic exercise stress test including eight of the nine patients with angiographic high risk coronary artery disease. It may be concluded therefore that coronary angiography to detect high risk coronary artery disease in this group can be restricted to patients with a positive exercise stress test. This policy would obviate the need for about 80% of coronary angiograms performed in this age group.     

Is there an indication for coronary angiography in patients under 60 years of age with no or minimal angina pectoris after a first myocardial infarction?

Coronary angiography and exercise stress tests were performed in 91 consecutive patients under 60 years of age having either no or only mild angina pectoris with or without medication after a first myocardial infarction. Nine (10%) patients had angiographic high risk coronary artery disease defined as three vessel disease, left main stenosis, or proximal stenosis of the left anterior descending artery. Eighteen patients had a positive electrocardiographic exercise stress test including eight of the nine patients with angiographic high risk coronary artery disease. It may be concluded therefore that coronary angiography to detect high risk coronary artery disease in this group can be restricted to patients with a positive exercise stress test. This policy would obviate the need for about 80% of coronary angiograms performed in this age group.     

Angiocardiography and Exercise Testing at One Month After a First Myocardial Infarction

Summary: Angiocardiography and exercise testing at one month after a first myocardial infarction. N. L. Sammel R. L. Wilson, R. M. Norris P. W. T. Brandt and J. G. Stuckey Aust. N.Z. J. Med ., 1980 10 , pp. 182–187
The results of exercise testing (77 patients), left ventriculography and coronary arteriography (78 patients) are presented for men under the age of 60, one month after a first myocardial infarct. Cineangiocardiography revealed that patients with anterior infarction (n = 25) had both poorer left ventricular function and more totally occluded vessels than those with either inferior (n = 33) or subendocardial infarction (n = 20). In contrast, patients with inferior and subendocardial infarction had a greater proportion of myocardium supplied by sub-total lesions likely to be haemodynamically significant (75%-99% cross sectional area loss). Subendocardial infarction was also characterised by the best left ventricular function and the fewest number of total coronary occlusions
Stress testing showed that the combination of ischaemic ST segment changes and angina during exercise was 91% predictive of severe coronary disease (equivalent to triple vessel disease) while no angina in the presence of a negative test was 81% predictive of mild or moderate disease. Stenoses of 75%-99% cross sectional area loss were more common when angina occurred during exercise testing, and both angina and ischaemic ST segment changes occurred within ten minutes in all four patients with haemodynamically significant left main coronary artery lesions
Our data supports the usefulness of exercise testing after a first myocardial infarct and may provide valuable baseline information in the analysis of long term prognosis     

Reciprocal ST depression in acute myocardial infarction.

ST segment depression in leads remote from those showing ST elevation during acute myocardial infarction has been attributed to benign electrical phenomena, distant myocardial ischaemia, or extensive myocardial damage. Eighty four consecutive survivors under 55 years of age with a first transmural myocardial infarction were studied. All patients had exercise tests six weeks after infarction and coronary angiography a mean of three months after infarction. Thirty eight (75%) of the 51 inferior and 19 (58%) of the 33 anterior infarcts showed reciprocal ST depression of greater than or equal to 1 mm during the acute phase. Ten (26%) of the 38 patients with inferior infarcts and reciprocal depression had ST depression in the same leads on exercise. There was concomitant disease of the left anterior descending artery in four (40%) of these 10 patients and in five (18%) of the 28 with inferior infarcts with reciprocal depression but without ST depression in the same leads on exercise. Five (26%) of the 19 patients with anterior infarcts with associated reciprocal depression and four of the 14 without reciprocal depression had important right coronary artery disease. In patients with inferior infarction important disease of the left anterior descending artery could not be predicted by ST depression in particular lead groups. Therefore reciprocal ST depression during acute myocardial infarction does not predict concomitant disease in the coronary artery supplying the reciprocal territory.     

Reciprocal ST depression in acute myocardial infarction

ST segment depression in leads remote from those showing ST elevation during acute myocardial infarction has been attributed to benign electrical phenomena, distant myocardial ischaemia, or extensive myocardial damage. Eighty four consecutive survivors under 55 years of age with a first transmural myocardial infarction were studied. All patients had exercise tests six weeks after infarction and coronary angiography a mean of three months after infarction. Thirty eight (75%) of the 51 inferior and 19 (58%) of the 33 anterior infarcts showed reciprocal ST depression of greater than or equal to 1 mm during the acute phase. Ten (26%) of the 38 patients with inferior infarcts and reciprocal depression had ST depression in the same leads on exercise. There was concomitant disease of the left anterior descending artery in four (40%) of these 10 patients and in five (18%) of the 28 with inferior infarcts with reciprocal depression but without ST depression in the same leads on exercise. Five (26%) of the 19 patients with anterior infarcts with associated reciprocal depression and four of the 14 without reciprocal depression had important right coronary artery disease. In patients with inferior infarction important disease of the left anterior descending artery could not be predicted by ST depression in particular lead groups. Therefore reciprocal ST depression during acute myocardial infarction does not predict concomitant disease in the coronary artery supplying the reciprocal territory.     

Prognostic significance of transient myocardial ischaemia after first acute myocardial infarction: five year follow up study.

OBJECTIVE--To assess the five year prognostic significance of transient myocardial ischaemia on ambulatory monitoring after a first acute myocardial infarction, and to compare the diagnostic and long term prognostic value of ambulatory ST segment monitoring, maximal exercise testing, and echocardiography in patients with documented ischaemic heart disease. DESIGN--Prospective study. SETTING--Cardiology department of a teaching hospital. PATIENTS--123 consecutive men aged under 70 who were able to perform predischarge maximal exercise testing. INTERVENTIONS--Echocardiography two days before discharge (left ventricular ejection fraction), maximal bicycle ergometric testing one day before discharge (ST segment depression, angina, blood pressure, heart rate), and ambulatory ST segment monitoring (transient myocardial ischaemia) started at hospital discharge a mean of 11 (SD 5) days after infarction. MAIN OUTCOME MEASURES--Relation of ambulatory ST segment depression, exercise test variables, and left ventricular ejection fraction to subsequent objective (cardiac death or myocardial infarction) or subjective (need for coronary revascularisation) events. RESULTS--23 of the 123 patients had episodes of transient ST segment depression, of which 98% were silent. Over a mean of 5 (range 4 to 6) years of follow up, patients with ambulatory ischaemia were no more likely to have objective end points than patients without ischaemic episodes. If, however, subjective events were included an association between transient ST segment depression and an adverse long term outcome was found (Kaplan-Meier analysis; P = 0.004). The presence of exercise induced angina identified a similar proportion of patients with a poor prognosis (Kaplan-Meier analysis; P < 0.004). Both exertional angina and ambulatory ST segment depression had high specificity but poor sensitivity. The presence of exercise induced ST segment depression was of no value in predicting combined cardiac events. Indeed, patients without exertional ST segment depression were at increased risk of future objective end points (Kaplan-Meier analysis; P < 0.0045). These findings may be explained in part by a higher prevalence of left ventricular dysfunction in patients without ischaemic changes in the exercise electrocardiogram (P < 0.05). CONCLUSION--There seem to be limited reasons to perform ambulatory ST segment monitoring in survivors of a first myocardial infarction who can perform exercise tests before discharge. Patients at high risk of future myocardial infarction or death from cardiac causes are not identified. Ambulatory monitoring and exertional angina distinguish a small subset of patients who will develop severe angina pectoris demanding coronary revascularisation during follow up. Patients without exercise induced ST segment depression comprise a high risk subgroup in terms of subsequent objective end points. The role of ambulatory ST segment monitoring performed in unselected patients immediately after infarction when risk is maximal remains to be clarified.     

Effects of streptokinase in patients presenting within 6 hours of prolonged chest pain with ST segment depression.

BACKGROUND--The effects of streptokinase on the occurrence of a combined clinical outcome in patients presenting with recent chest pain and ST depression were investigated in view of the role of thrombus in the pathogenesis of acute ischaemic syndromes. METHODS--112 patients aged < or = 75 years presenting within 6 h of the last episode of ischaemic chest pain of least 20 min duration with > or = 1 mm ST depression were randomised in a double blind manner to receive either streptokinase 1.5 million units over 30 min (n = 57) or placebo (n = 55). The primary end point was the combination of death, frequency of myocardial infarction (defined as peak creatine kinase > 600 U/ml), need for angiography because of uncontrollable ischaemia, and an exercise test within 35 days showing > or = 1 mm ST depression at < or = 6 min. The secondary end points were safety, frequency of chest pain, readmission with myocardial infarction or unstable angina, or need for revascularisation between 35 days and 1 year. The severity of ST depression on presentation was analysed with respect to clinical outcome. RESULTS--The frequency of the combined hierarchical end point of death, myocardial infarction, early angiography, and a positive exercise test was 82% (47 of 57 patients) with streptokinase and 75% (41 of 55 patients) with placebo. There were four deaths, two in each group. 27 patients (47%) receiving streptokinase and 22 (40%) receiving placebo developed myocardial infarction. 11 patients (eight streptokinase and three placebo) required coronary arteriography and subsequent revascularisation because of angina uncontrolled by medical treatment. 44 patients (22 in each group) had a positive exercise test. There were three further cardiac deaths (one streptokinase, two placebo), and three noncardiac deaths within 1 year. A conservative approach to intervention was adopted and over a period of 1 year 29 patients (26%) (13 streptokinase and 16 placebo) underwent revascularisation procedures. Three patients (two streptokinase and one placebo) required transfusion. ST depression > or = 3 mm had 90% specificity but only 60% positive predictive value for myocardial infarction at presentation (P = 0.008, stepwise logistic regression). ST depression > or = 2 mm was predictive of death, late development of myocardial infarction, or a need for angiography (P = 0.02). CONCLUSION--Patients presenting with ischaemic chest pain and ST depression frequently develop myocardial infarction. Severe ST depression is predictive of an adverse outcome. The 35 day (3.6% cardiac and total) and 1 year mortality (8.9% total, 6.3% cardiac) are low with conservative management and expeditious revascularisation. Streptokinase treatment within 6 h of the last episode of pain does not seem to be beneficial.     

The diagnostic inadequacy of exercise testing in critical left coronary artery disease

Coronary cinearteriograms were consecutively reviewed to identify “critical” (75% or more stenosis) left coronary artery (LCA) disease in patients who had previously been electrocardiographically monitored during submaximal stress by ergometry (GXT). There were 26 such patients with lesions of the left main coronary artery or its equivalent (proximal left anterior descending and left circumflex branches), and two of the left anterior descending proximal to the large septal perforator. A positive GXT was identified by ST depression of 1 mm or more persisting for 0.08 sec. Exercise was terminated when symptoms, exhaustion, a threatening response (4mm or more ST depression) or 85% predicted maximal rate (PMR) occurred. There were 13 (46%) positive and 15 (54%) negative GXTs. Three of the positive group and five negative responders had a previous myocardial infarction which was located anteriorly in two and three cases respectively (P=NS). Asynergy was observed in seven patients in each group and was anterior in location in four and six patients respectively (P=NS). There was no significant difference in the incidence of impaired contractility or in cardiodynamic evidence of left ventricular dysfunction in either group. Five of 15 patients with negative GXT (18% of entire group) achieved 85% or more PMR. Eleven of this group achieved a rate of more than 110/min.Although the substantial incidence of false negative exercise tests in multiple vessel coronary artery disease is well known, its frequency in “critical” LCA stenoses has not previously been emphasized.     

Significance of hemiblock of the left branch during exercise

There have been few reports of exercise induced left branch hemiblock. In order to assess its frequency and significance, a retrospective study of 8684 patients was undertaken: 24 cases (11 anterior and 13 posterior) were recensed. Nineteen of these patients had typical effort angina, 3 had a history of myocardial infarction and 3 had aortiocoronary bypass surgery. Twenty patients developed ST-T wave abnormalities included 11 ST segment depressions. Four patients refused coronary angiography: 3 of these patients had probable coronary artery disease (typical effort angina, positive exercise stress tests and in 1 case, inferior wall hypofixation during myocardial scintigraphy). Twenty patients underwent coronary angiography. In 2 patients, the exercise stress test was performed under Class IC antiarrhythmic therapy; 1 had a normal coronary angiogram and the other had patient coronary bypass graft. A control exercise stress test after withdrawal of drug therapy was negative in these 2 cases. The other 18 patients had significant coronary artery disease. The recording of left branch hemiblock during exercise stress testing would seem to indicate severe coronary artery narrowing (greater than or equal to 90% in 15 cases; greater than or equal to 80% in 3 cases) and left anterior hemiblock is indicative of left main coronary or proximal left anterior descending artery disease. In this series, medical therapy did not make exercise-induced left branch hemiblock regress, in contrast to aortocoronary bypass surgery and angioplasty.     

Detection, frequency and clinical significance of silent myocardial ischaemia in patients with chronic stable angina

Forty-two patients (mean age 50 years) with chronic stable angina pectoris were subjected to exercise treadmill testing, coronary arteriography and left ventricular cineangiography. Twenty-one of these patients also underwent Holter monitoring for 24 hours. On exercise treadmill testing, angina was the endpoint in 24 (57%), while 18 (43%) developed significant ST segment depression without symptoms. Holter monitoring in 27 patients revealed a total of 248 episodes of myocardial ischaemia of which 210 (84%) were asymptomatic. ST segment depression at 80 mS from J point varied from 1 to 4 mm, and the average duration of ischaemic episodes during Holter monitoring was 9 minutes (range 30 seconds to 1 hour). Heart rate during the ischaemic episodes varied between 65-85 beats/minute. Coronary angiography revealed triple vessel disease in 22 (52%) and double vessel and single vessel involvement in 10 (24%) each. Left ventricular ejection fraction was less than 50% in only 3 (7%) patients. Thus silent myocardial ischaemia is detected frequently in patients with angina pectoris. It occurs during routine daily activity, and on exercise. Heart rate at which silent myocardial ischaemia occurs is much less during daily activity as compared to exercise induced ischaemia. All patients who were detected to have silent myocardial ischaemia had significant coronary artery disease. These findings are of prognostic and therapeutic value.     

Indication for coronary revascularization for angina pectoris: correlation with prognosis of medically-treated patients

To assess the indication for percutaneous transluminal coronary angioplasty (PTCA) and coronary artery bypass grafting (CABG), we studied 93 patients with angina pectoris but without myocardial infarction. All patients had significant stenosis (greater than 50%) in at least one coronary artery, including the left anterior descending artery. Fifty-eight patients received medical treatment (Group I), 12 had PTCA (Group II) and 23 had CABG (Group III). Findings of coronary angiography, treadmill exercise tests and dipyridamole perfusion scintigraphy as well as the frequency of cardiac events during follow-up were assessed in each group. 1. Coronary angiography revealed 1 vessel disease in 38% of the patients in Group I, 58% in Group II, and 13% in Group III; 2 vessel disease in 33%, 25% and 61%; and 3 vessel disease in 29%, 17% and 26%, respectively. 2. Exercise duration with the treadmill test was 4.7 min in Group I, 4.0 min in Group II and 3.7 min in Group III. ST depression (greater than or equal to 1 mm) was induced in 75%, 83% and 95%, respectively. Exercise duration improved from 4.0 to 6.0 min after PTCA and from 3.7 to 4.5 min after CABG. Exercise-induced ST depression also became less frequent; from 83% to 25% after PTCA and from 95% to 32% after CABG. Dipyridamole perfusion scintigraphy showed reversible defects in 86% of the patients in Group I and in all patients in Groups II and III. Reversible defects were observed in 17% of the patients after PTCA and in 21% after CABG. 3. During a mean follow-up period of 26 months, cardiac deaths occurred in one patient (2%) in Group I and 2 (7%) in Group III. Nonfatal cardiac events (myocardial infarction and unstable angina or those necessitating revascularization--late PTCA or CABG) were observed in 12 patients (21%) in Group I, 4 (24%) in Group II and 10 (36%) in Group III. Anginal attacks at least once weekly remained in 12% of the patients in Group I, 19% in Group II and 14% in Group III at the last follow-up. In conclusion, PTCA and CABG appear to be effective methods for improving ischemia and exercise tolerance. However, preventive PTCA and CABG may not be indicated in patients with mild angina, because the prognosis is also excellent in medically-treated patients with angina but without myocardial infarction or left main coronary artery disease.     

Mental arithmetic stress testing in patients with coronary artery disease

A mental arithmetic stress test was performed by 122 consecutive patients undergoing diagnostic coronary arteriography. Twenty-two patients showed significant ST segment abnormalities during the test (group 1). Of these patients, 20 performed a bicycle exercise test, which was positive in all of them. Seventy patients had a negative mental stress but a positive exercise test (group 2), whereas in 30 patients both tests were negative (group 3). There were no patients with a positive mental stress test and a negative exercise test. Mental stress induced a significant increase in heart rate and systolic blood pressure in the three groups of patients. Group 1 patients, however, achieved higher values of double product during mental stress and had a shorter exercise duration than group 2 and group 3 patients. The extent of coronary artery disease (CAD) was similar in groups 1 and 2, while group 3 patients had a significantly lower prevalence of two or more vessel disease. To investigate the pathogenetic mechanism of mental stress-induced myocardial ischemia, great cardiac vein flow was measured by means of the thermodilution technique in four patients with isolated left anterior descending artery disease, who showed ST segment depression in anterior leads in response to mental stress. In three patients without vasospastic angina the calculated coronary resistance decreased during mental stress, as a result of a normal vasodilatory response to the increased myocardial oxygen consumption induced by the test. By contrast, in one patient with variant angina, coronary resistance increased suggesting coronary vasoconstriction. Our findings demonstrate that mental arithmetic stress testing may induce significant ST segment abnormalities in patients with CAD. Such patients respond to mental stress with a disproportionate increase in myocardial oxygen consumption and have decreased exercise capacity. Although coronary resistance generally decreases during mental stress-induced myocardial ischemia, coronary vasoconstriction may occur in patients with variant angina.     

Increased exercise thallium-201 lung uptake: a noninvasive prognostic index in two-vessel coronary artery disease

To determine the physiologic impact of two-vessel coronary artery disease and its effect on prognosis, a series of clinical, angiographic, exercise and quantitative thallium-201 (Tl-201) imaging parameters were analyzed in 85 consecutive two-vessel coronary artery disease patients followed for 52 +/- 27 months after coronary angiography and Tl-201 scintigraphy. End points were cardiac death (n = 3), myocardial infarction (n = 6) and coronary bypass graft surgery more than three months after testing (n = 16). Using Cox Hazards survival analysis, early cardiac events were not predicted by: myocardial infarction or anginal history; resting left ventricular function; exercise blood pressure response; angina or severity of ECG ST segment depression (mm); Tl-201 defect size; redistribution or clearance; angiographic patterns; or the presence of proximal left anterior descending disease. Significant predictors of adverse cardiac events were: increased exercise lung to heart Tl-201 ratio (0.59 +/- 0.12 versus 0.46 +/- 0.1; P less than 0.0001); ECG lead extent of ST segment depression (P less than 0.03); and exercise heart rate response (P less than 0.047). Event-free survival for patients with normal and abnormally increased lung to heart Tl-201 ratios at 48 months was 76% versus 63% (P less than 0.003). It was concluded that two-vessel coronary artery disease survival correlates with exercise Tl-201 uptake which reflects exercise induced left ventricular dysfunction.     

The significance of a persistent precordial ST segment greater than or equal to 0.1 mV depression in acute inferior myocardial infarction (coronary angiographic and ventriculographic findings)

40 patients with acute inferior myocardial infarction (MI) associated with persistent precordial ST segment depression greater than or equal to 0.1 mV underwent coronary arteriography and left ventriculography within 5-6 days of their admission. The inferior MI was the result of complete occlusion of the right coronary artery (RCA) in 38 patients and the result of complete occlusion of the posterior descending artery (PDA) coming off the circumflex artery (Cx) in two patients. 36 (90%) of the 40 patients showed one or more severe stenoses in the left anterior descending artery (LAD). 12 of the 36 patients had severe triple vessel disease. The 36 patients whose coronary arteriograms showed significant LAD stenosis had an emergency coronary artery by pass graft (CABG) operation. Soon afterwards the precordial leads were normal and the patients free of angina till their discharge from hospital. We conclude that a persistent precordial ST segment greater than or equal to 0.1 mV depression in acute inferior MI is highly predictive of significant LAD disease.     

Incidence, clinical characteristics, and short-term prognosis of angina pectoris.

OBJECTIVES--To estimate the clinical incidence and short-term prognosis of patients presenting with typical angina pectoris in the general population. DESIGN--Prospective survey of all patients referred by 117 general practitioners from a random sample of 17 general practices serving a population of 191,677 with a median follow up of 16 months. SETTING--A special open access chest pain clinic, based in the non-invasive cardiology department of a teaching hospital, set up for this study. PATIENTS--110 consecutive patients < or = 70 years age with no history of coronary heart disease presenting for the first time with typical angina. MAIN OUTCOME MEASURES--Age and sex specific incidences, persistence of chest pain, revascularisation procedures, myocardial infarction, and death. RESULTS--The crude annual incidence of angina pectoris (95% confidence interval) was 0.83 (0.66 to 1.0) per thousand population aged 31-70 years; the rates were 1.13 (0.85 to 1.40) for men and 0.53 (0.33 to 0.72) for women. On resting electrocardiography 5% of patients had > or = 1 mm horizontal or downsloping ST depression, 5% had Q/QS patterns, and in one (1%) there was complete left bundle branch block. Among the 103 patients who underwent a Bruce protocol exercise test, 29% had > or = 3 mm ST segment depression induced at a low workload. Of 107 patients at a median (range) follow up of 15.8 (7-30) months, angina remitted spontaneously in 12 patients (11%), 20 (19%) underwent revascularisation, eight (7%) sustained a non-fatal myocardial infarction, and four (4%) died. CONCLUSION--Incidence of new cases of angina pectoris in the United Kingdom is conservatively estimated from this study to be 22,600 patients per annum. Almost one third of these patients will have positive exercise tests at low workload, so the potential for coronary angiography and revascularisation is considerable. With one in 10 patients experiencing a non-fatal myocardial infarction or coronary death within a year of presentation the prognosis of angina is not benign. Further research is required to identify those patients in the general population who would benefit most from coronary revascularisation.     

Exercise-induced ST elevation in patients without myocardial infarction.

A review of 6040 consecutive exercise tests yielded 106 patients without previous myocardial infarction (MI) who had exercise-induced ST elevation (greater than or equal to 0.5 mm in a 15-lead ECG system). In 46, ST elevation was correlated with left ventriculography and coronary angiography. Coronary artery disease (CAD) (greater than or equal to 70% narrowing) was detected in 40 of 46 patients: 12 patients had one-vessel disease, 13 had two-vessel disease, and 15 had three-vessel disease. Resting ventriculograms were normal in 36 of 40 patients. Of 21 patients with anterior (V1-V3) ST elevation, 86% had a left anterior descending (LAD) obstruction and 78% had obstruction proximal to the first diagonal branch. LAD disease occurred significantly more frequently than right and circumflex CAD. There was no anatomic correlation of three persons with lateral (leads V4--6, I or aVL) or 27 patients with inferior-posterior (leads II, III, aVF, Y or Z) exercise-induced ST elevation. Therefore, exercise-induced ST elevation is strongly correlated with CAD but not resting wall motion abnormalities. Further, anterior exercise-induced ST elevation in patients without a previous MI often predicts a significant proximal LAD obstruction.     

Effects of recent and remote infarction on the predictive accuracy of the ST segment/heart rate slope

The exercise electrocardiographic ST segment/heart rate slope accurately identifies three vessel coronary disease in patients with stable angina, but the method is less accurate in predischarge testing after recent myocardial infarction. To assess the effect of both recent (less than 3 weeks) infarction and remote (greater than 8 weeks) Q wave infarction on the ST segment/heart rate slope, the predictive value of a slope greater than 6.0 microV/beat per min for the identification of three vessel coronary artery disease was evaluated in 113 patients. The 58 patients with stable angina, including 17 with remote Q wave myocardial infarction, were similar to the 55 patients with recent myocardial infarction with respect to age and peak exercise heart rate. In patients with stable angina and no prior Q wave myocardial infarction, an ST segment/heart rate slope greater than 6.0 had a sensitivity of 92% (11 of 12), a specificity of 97% (28 of 29) and a positive predictive value of 92% (11 of 12) for three vessel coronary artery disease. In patients with stable angina and remote Q wave infarction, sensitivity was 83% (5 of 6), specificity was 91% (10 of 11) and positive predictive value was 83% (5 of 6). After recent infarction, test specificity for three vessel disease was preserved at 95% (39 of 41), but test sensitivity was poor (3 of 8). This was confirmed by evaluation of six additional recent patients with infarction and three vessel disease. Among the combined group with recent infarction, test sensitivity for three vessel disease was only 29% (4 of 14), significantly lower than in patients with stable angina (p less than 0.005).(ABSTRACT TRUNCATED AT 250 WORDS)