Relationship among mental stress-induced ischemia and ischemia during daily life and during exercise: the Psychophysiologic Investigations of Myocardial Ischemia (PIMI) study.

OBJECTIVES: The purposes of this database study were to determine: 1) the relationship between mental stress-induced ischemia and ischemia during daily life and during exercise; 2) whether patients who exhibited daily life ischemia experienced greater hemodynamic and catecholamine responses to mental or physical stress than patients who did not exhibit daily life ischemia, and 3) whether patients who experienced daily life ischemia could be identified on the basis of laboratory-induced ischemia using mental or exercise stress testing. BACKGROUND: The relationships between mental stress-induced ischemia in the laboratory and ischemia during daily life and during exercise are unclear. METHODS: One hundred ninety-six stable patients with documented coronary disease and a positive exercise test underwent mental stress testing and bicycle exercise testing. Radionuclide ventriculography and electrocardiographic (ECG) monitoring were performed during the mental stress and bicycle tests. Patients underwent 48 h of ambulatory ECG monitoring. Hemodynamic and catecholamine responses were obtained during mental stress and bicycle tests. RESULTS: Ischemia (reversible left ventricular dysfunction or ST segment depression > or = 1 mm) developed in 106 of 183 patients (58%) during the mental stress test. There were no significant differences in clinical characteristics of patients with, compared with those without, mental stress-induced ischemia. Patients with mental stress ischemia more often had daily life ischemia than patients without mental stress ischemia, but their exercise tests were similar. Patients with daily life ischemia had higher ejection fraction and cardiac output, and lower systemic vascular resistance during mental stress than patients without daily life ischemia. Blood pressure and catecholamine levels at rest and during the mental stress tests were not different in patients with, compared with those without, daily life ischemia. Patients with daily life ischemia had a higher ejection fraction at rest and at peak bicycle exercise compared with patients without daily life ischemia, but there were no other differences in peak hemodynamic or catecholamine responses to exercise. The presence of ST segment depression during routine daily activities was best predicted by ST segment depression during mental or bicycle exercise stress, although ST segment depression was rare during mental stress. CONCLUSIONS: Patients with daily life ischemia exhibit a heightened generalized response to mental stress. ST segment depression in response to mental or exercise stress is more predictive of ST segment depression during routine daily activities than other laboratory-based ischemic markers. Therapeutic management strategies might therefore focus on patients with these physiologic responses to stress and on whether lessening such responses reduces ischemia.     

Exercise-induced prolongation of the infarct-related Q-waves as a marker of myocardial viability in the infarcted area

OBJECTIVE: It is known that exercise-induced ischemia in patients with coronary artery disease (CAD) may produce QRS prolongation in the surface electrocardiogram (ECG). To investigate the presence of exercise-induced Q-wave prolongation in patients with single-vessel CAD and Q-wave myocardial infarction (MI), in association with the presence of reversible perfusion defects during thallium scintigraphy in the infarcted area. METHODS: 107 consecutive patients (89 males, mean age 56+/-8 years) were evaluated. All patients underwent coronary arteriography, maximal treadmill exercise testing and thallium-201 scintigraphy. Q-wave duration was measured both before exercise testing and during maximal heart rate from 12-lead ECGs recorded with a paper speed of 50 mm/s. RESULTS: Only 57 out of the 107 studied patients showed reversible perfusion defects in the infarcted area during thallium scintigraphy. Q-wave duration was significantly increased from the resting to the stress ECG (DeltaQ-wave duration) in patients with reversible perfusion defects in the infarcted areas (10+/-13 ms), but not in patients with fixed defects in the infarcted zone (-2.0+/-5 ms, p<0.01). The sensitivities and the specificities of Q-wave prolongation, ST segment elevation, and the combination of ST segment elevation with ST segment depression in the reciprocal leads for the detection of myocardial viability in the infarcted area were 82%, 48%, 29% and 88%, 50%, and 90%, respectively. CONCLUSIONS: Exercise-induced Q-wave prolongation is demonstrated in those patients with single-vessel CAD and a recent MI who show reversible perfusion defects in thallium scintigraphy. Exercise-induced Q-wave prolongation was found to be a sensitive and specific ECG marker for the detection of myocardial viability in the infarcted area.     

Exercise test parameters after acute myocardial infarction. Relationship with coronary angiography]

OBJECTIVE: To analyze the relation between characteristics of symptom-limited treadmill exercise stress test, after acute myocardial infarction (MI) and coronariographic results (number of diseased vessels). Both tests were performed before hospital discharge. DESIGN: Retrospective study with comparative analysis between variable defined groups. POPULATION AND SETTING: From 232 patients interned in the department of Cardiology of Hospital de Santa Marta with a first acute MI, a population of 112 patients submitted to exercise stress test and coronary angiography before discharge were selected (aged 29 to 69 years). METHODS: Symptom-limited treadmill exercise stress tests were performed according to Bruce protocol, with no heart-rate limitation. The following parameters were analyzed: Stress test duration (DUR); Double product variation (varDP); Metabolic equivalent units (METS); Maximal heart rate (FCmax); Percentage of the maximal reached heart rate (% FCmax); Incidence of ST segment depression (InfST); Maximal ST segment depression (Max-InfST); Onset minute of ST segment depression (MinInfST); Heart rate at the onset of ST segment depression (FCInfST); Double product at the onset of ST segment depression (DPInfST); Recovery minute of ST segment depression (MinRInfST); Onset minute of angina (MinAng); Heart rate at the onset of angina (FCAng); Double product at the onset of angina (DPAng). RESULTS: Statistical significant differences were obtained between coronariographic groups concerning the following parameters: DUR: 1-vessel/3-vessel P = 0.02; VarDP: 1-vessel/3-vessel p = 0.008, 2-vessel/3-vessel p = 0.004; METS: 1-vessel/3-vessel p = 0.01. No differences were seen between anterior and inferior myocardial infarctions regarding all the stress test parameters. However in patients with anterior MI significant differences were obtained concerning the following variables: VarDP: 1-vessel/2-vessel p = 0.02; InfraST: 1-vessel/2-vessel p = 0.006, 1-vessel/3-vessel p = 0.03; MaxInfST: 1-vessel/2-vessel p = 0.01, 1-vessel/3-vessel p = 0.0006; Angina: 1-vessel/2-vessel p = 0.0005, 1-vessel/3-vessel p = .001. In inferior myocardial infarctions only the stress duration differed between 1-vessel and 3-vessel groups (p = 0.003). CONCLUSIONS: Symptom-limited treadmill exercise stress tests, safely performed in our institution, were an important method for post MI evaluation and allowed the diagnosis of a great number of patients with residual ischemia. Statistical significant differences were found in ergometric parameters, between coronariographic groups (defined by the number of diseased vessels), emphasising the importance of stress tolerance analysis.     

Symptomatic and silent myocardial ischemia during exercise testing in coronary artery disease

During exercise by patients with coronary artery disease (CAD), electrocardiographic evidence of myocardial ischemia may precede the onset of angina or may be unassociated with angina, even at peak levels of stress. However, neither the precise incidence of silent versus symptomatic ischemic episodes nor their interrelation in this setting has been clearly defined. The prevalence of silent and symptomatic myocardial ischemia during treadmill exercise testing was determined in 92 patients with angiographically documented CAD. The study group comprised 77 men (84%) and 15 women (16%) of mean age 57 years (range 32 to 79). Exercise testing resulted in ischemic ST-segment depression (greater than or equal to 1 mm for greater than or equal to 80 ms) only or in association with delayed (greater than or equal to 1 minute) angina in 39 patients (42%); angina only or in association with delayed ST-segment depression occurred in 42 patients (46%); and simultaneous occurrence of angina and ST-segment depression was noted in 11 patients (12%). Analysis of clinical, exercise and angiographic factors (age, sex, history of myocardial infarction, heart rate, maximal ST-segment depression, extent of CAD and left ventricular ejection fraction) revealed no significant correlation with the frequency of symptomatic and silent myocardial ischemia during exercise. Asymptomatic myocardial ischemia occurred commonly during exercise in patients with CAD, but there were no differences in the characteristics of patients with symptomatic and asymptomatic episodes.     

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.     

ST segment changes in exercise body surface mapping after myocardial infarction in patients with isolated left anterior descending coronary artery disease

To investigate the clinical significance of exercise-induced ST segment elevation and ST segment depression after myocardial infarction (MI), we performed 87-lead ECG mapping after previous anterior infarction in 24 patients with isolated left anterior descending coronary artery disease before and 1.5 minutes after treadmill exercise. Thirteen patients showed ST segment elevation only, seven patients showed both ST segment elevation and depression, and four patients showed ST segment depression only. ST segment elevation most frequently occurred in the left anterior chest leads corresponding to the QS area, and ST segment depression developed in the left lower chest and left lower back leads. There was good correlation between the number of lead points showing ST segment elevation (nSTe) after exercise and the number of lead points showing QS waves (nQS) before exercise (r = 0.65). nSTe was also correlated with the asynergy index (r = 0.43). These findings suggest that ST segment elevation is mainly the result of aggravation of wall motion abnormalities of the infarcted myocardium. Body surface distribution of ST segment depression was similar to that in effort angina pectoris without MI. We conclude that exercise-induced ST segment depression in MI mainly reflects the ischemia of the surviving myocardium of small infarcts or the peripheral area of large infarcts.     

Atrial pacing and thallium 201 scintigraphy: combined use for diagnosis of coronary artery disease

To evaluate the presence of coronary artery disease (CAD), atrial pacing and thallium 201 scintigraphy were performed in 36 patients with stable angina pectoris who were unable to perform an adequate exercise stress test. All patients underwent cardiac catheterization. Nine patients had previously undergone coronary artery bypass surgery. Significant CAD (one or more lesions greater than or equal to 50%) was present in 33 patients. Atrial pacing produced ischemic ST segment depression (greater than or equal to 1 mm) in 18 (55%) patients with CAD, and angina in 20 patients (61%). As the number of vessels with CAD increased, there was no significant change in the sensitivities of pacing-induced angina or ST segment depression for detecting CAD. In the 3 patients without CAD, ST segment depression occurred in 1 patient and angina in none. Thallium 201 scintigraphy demonstrated perfusion defects in 27 (82%) patients with CAD, with fixed defects seen in 13 studies (39%) and reversible defects in 15 (45%). In the 3 patients without CAD, no perfusion defects were seen. The thallium 201 scan successfully predicted the presence of CAD in patients with single-vessel disease but usually underestimated the number of vessels involved in patients with multivessel disease. Combined sensitivity of pacing-induced ST segment depression and an abnormal thallium 201 scan finding for detecting CAD was 91%. The authors conclude that combined atrial pacing and thallium 201 scintigraphy is a useful test for detecting CAD in patients unable to perform an adequate exercise stress test.     

Clinical significance of stress-induced ST segment elevation in patients with previous anterior myocardial infarction. Analysis of lactate metabolism with atrial pacing

To clarify the mechanism of stress-induced ST segment elevation in patients with previous anterior myocardial infarction, we examined myocardial lactate metabolism during atrial pacing in 32 patients with previous anterior myocardial infarction (MI group) and 11 control subjects (control group). In the MI group, atrial pacing resulted in new or additional ST segment elevation in leads with Q waves in 15 patients (ST elevation group), ST segment depression in 7 (ST depression group), but induced no appreciable ST segment changes in the remaining 10 patients (ST unchanged group). In all patients, the ST segment changes were identical to the results of exercise stress testing which was carried out prior to the atrial pacing. Lactate extraction ratio increased moderately during the atrial pacing in the control group (p less than 0.01). Although marked reduction of the myocardial lactate extraction ratio was noted in the ST depression group (p less than 0.05), no significant change in the ratio was evoked in the ST elevation group or the ST unchanged group during atrial pacing. Left ventricular end-diastolic pressure (LVEDP) increased markedly in the ST depression group during atrial pacing, but the elevation was less evident in the other groups. The ST elevation group demonstrated the lowest left ventricular ejection fraction and the severest degree of left ventricular asynergy. Thus, the present study indicates that aggravated left ventricular asynergy in the infarcted area and associated left ventricular dysfunction, rather than peri-infarction zone ischemia is a possible mechanism of stress-induced ST segment elevation in leads with Q waves following previous anterior myocardial infarction.     

Prevalence of silent myocardial ischemia in survivors of cardiac arrest

The prevalence and type of ischemia (silent vs painful) in survivors of cardiac arrest not associated with acute myocardial infarction were studied to test the hypothesis that survivors may have an increased prevalence of silent ischemia. Of 48 survivors of cardiac arrest over a 4-year period who had undergone exercise testing, 24 met inclusion criteria. These 24 subjects had documented ventricular fibrillation and coronary artery disease proven by cardiac catheterization or a previous electrocardiographic pattern of myocardial infarction. Thirteen of 24 (54%) had a positive treadmill stress test (greater than or equal to 1.0 mm flat or downsloping ST depression). The mean resting left ventricular ejection fraction was 43%. Nine of 11 patients (82%) who had exercise radionuclide studies performed had ischemic abnormalities (less than 5% increase in left ventricular ejection fraction with new or worsened wall motion abnormalities). Thus, 16 of 24 (67%) had a positive treadmill stress test or radionuclide ventriculogram. Only 1 of 16 (6%) had painful ischemia (p less than 0.001 relative to an even distribution of painful vs painless ischemia). Thus, survivors of cardiac arrest have a high prevalence of exercise-induced ischemia, and in most the ischemia is silent.     

Incidence of acute myocardial infarction in patients with exercise-induced silent myocardial ischemia

Fifty-five patients with angiographically proved coronary artery disease (CAD) underwent Bruce protocol exercise stress testing with thallium-201 imaging. Twenty-seven patients (group I) showed myocardial hypoperfusion without angina pectoris during stress, which normalized at rest, and 28 patients (group II) had a similar pattern of reversible myocardial hypoperfusion but also had angina during stress. Patients were followed for at least 30 months. Six patients in group I had an acute myocardial infarction (AMI), 3 of whom died, and only 1 patient in group II had an AMI (p = 0.05), and did not die. Silent myocardial ischemia uncovered during exercise stress thallium testing may predispose to subsequent AMI. The presence of silent myocardial ischemia identified in this manner is of prognostic value, independent of angiographic variables such as extent of CAD and left ventricular ejection fraction.     

Stress myocardial scintigraphy in coronary artery disease: its clinical significance]

To evaluate the clinical significance of asymptomatic ischemic heart disease, exercise electrocardiography and stress myocardial scintigraphy were performed. These were correlated with symptoms during exercise tests and histories of myocardial infarction (MI). The study subjects consisted of 70 patients with coronary artery disease, including 34 with MI, and 36 without MI but with angina pectoris. Stress tests were performed using bicycle ergometer under electrocardiographic monitoring throughout the test. Transient myocardial ischemia was confirmed by perfusion defects on thallium myocardial imaging demonstrated immediately after exercise, but not 3 hours after the stress test. Asymptomatic ST depression was observed in 18 of 34 patients with MI (53%) and in 21 of the 36 patients with angina (58%); however, transient myocardial perfusion defects were confirmed in 61% of the patients with MI (11 of 18 patients), but in only 33% of those with angina (7 of 21 patients). The difference was statistically significant (p less than 0.05). It was suggested that there are some differences in the clinical significance of asymptomatic ST depression between the patients with MI and those without MI but with angina pectoris.     

24小时动态心电图对冠心病的诊断价值

对41例胸痛患者进行24小时动态心电图(AECG)及冠状动脉造影检查,其中24例在作上述检查2—3周内进行平板运动试验。10例正常冠状动脉患者AECG显示心肌缺血者仅1例,特异性90％;冠状动脉病变31例中显示心肌缺血20例,敏感性65％。心肌缺血检出敏感性与冠状动脉病变程度有关,多支病变为78％,单支病变为46％(P<0.01).AECG对单支病变患者,心肌缺血检出率明显低于平板运动试验(P<0.01);对多支病变患者,心肌缺血检出率与平板运动试验相同,均为88％。     

Usefulness of the postexercise response of systolic blood pressure in the diagnosis of coronary artery disease

The normal decline in systolic blood pressure (SBP) during the recovery phase of treadmill exercise does not occur in some patients with coronary artery disease (CAD). In others the recovery values of SBP exceed the peak exercise values. To examine the diagnostic value of this observation, we studied 31 normal subjects and 56 patients undergoing treadmill exercise before coronary cineangiography. Because of large differences in peak exercise pressures between the two groups, recovery ratios were derived by dividing the SBP at 1, 2, and 3 min after exercise by the peak exercise SBP. The 1, 2, and 3 min ratios in the normal subjects declined steadily from 0.85 +/- 0.07 (SD) to 0.79 +/- 0.06 and to 0.73 +/- 0.06, respectively, while the ratios in the patients with CAD remained elevated at 0.97 +/- 0.12 to 0.97 +/- 0.11 to 0.93 +/- 0.13. With use of the upper limits defined by two SDs of the normal value, recovery ratios were compared with the occurrence of angina and with ST segment depression on the exercise electrocardiogram in the patients with CAD. Abnormal ratios were more frequent in patients with CAD (53/56, 95%) than in those with ST segment depression (33/56, 59%), angina (37/56, 66%), and either ST segment depression or angina (42/56, 75%). Twenty of the patients with CAD who were on no medication underwent an additional treadmill exercise test on a separate day and no significant differences were found in the ratios from the two tests. Ten additional patients with CAD underwent treadmill exercise testing while on placebo and while on a beta-blocker.(ABSTRACT TRUNCATED AT 250 WORDS)     

Usefulness of early exercise testing after non-Q-wave myocardial infarction in predicting prognosis

The value of an early symptom-limited maximal exercise test in predicting coronary anatomy, left ventricular ejection fraction and hemodynamics was assessed prospectively in 64 patients after an acute non-Q-wave myocardial infarction (MI). Exercise tests and cardiac catheterization were performed at a median of 6 and 7 days, respectively, after non-Q MI. Forty-one percent of the patients had a negative exercise test response (no angina, less than 1 mm of ST depression and normal blood pressure responses). Twenty-five percent had a positive response (1 to 1.9 mm of ST depression or angina); 34% had a "strongly positive" exercise test response (at least 2 mm of ST depression or abnormal blood pressure responses). A negative response predicted the absence of 3-vessel disease (at least 70% stenosis) or critical stenoses (at least 90% stenosis) involving major coronary arteries (negative predictive accuracy 92%), whereas a strongly positive response predicted their presence (positive predictive value 77%, specificity 88%). Cardiac index and mean pulmonary artery wedge pressure did not vary significantly among the 3 exercise groups, whereas left ventricular ejection fraction was slightly higher in the exercise test group with a positive response (p less than 0.025). Thus, in patients who have had a non-Q MI, early exercise testing can be used to predict the extent and severity of coronary artery disease, and the decision to perform coronary angiography should be guided by the exercise test results.     

Transient ST-segment depression as a marker of myocardial ischemia during daily life

Patients with angina and coronary artery disease (CAD) have many episodes of transient ST-segment depression during ordinary daily life, and these are often asymptomatic. To investigate this signal as a marker of myocardial ischemia, 30 patients with chronic stable angina and CAD underwent positron tomography, recording the regional myocardial uptake of rubidium-82, pain and ST-segment changes before, during and after 59 technically satisfactory exercise tests, 35 cold pressor tests and 22 episodes of unprovoked ST depression. Exercise resulted in 53 episodes of ST depression with angina and in 5 episodes without pain. After cold pressor tests, there were 3 episodes of ST depression and pain and 12 of painless ST depression. Only 9 episodes of unprovoked ST depression were accompanied by pain. Tomography showed independent evidence of ischemia in 63 (97%) of the total 65 episodes of ST depression with angina and in all 30 episodes of painless ST depression. In each patient perfusion defects occurred in the same myocardial segment during painful and painless ST depression and responses were significantly different from those in 16 normal subjects studied in the same way. These findings support the use of transient ST depression in continuous monitoring to assess the activity of CAD, but only in patients with typical angina pectoris, ST depression during exercise and proved CAD. They strengthen the evidence derived from ambulatory monitoring for a wider picture of the disease than is generally appreciated, with more frequent episodes of silent myocardial ischemia than of angina pectoris.     

Usefulness of dobutamine in producing myocardial ischemia. Comparison with ergometry

Fifty six patients were studied while in the Coronary Care Unit: 17 with unstable angina and 39 with acute myocardial infarction. All patients underwent dobutamine stress testing (doses of 5, 10, 15 and 20 micrograms/kg/min every 5 min) and exercise testing (modified protocol to finish at an energy expenditure of approximately 5 METS): 4-5 days after the last crisis of angina or 6-8 days after the onset of noncomplicated acute myocardial infarction. The heart rate increased from 72 +/- 10 to 104 +/- 12 beat/min with dobutamine (p = 0.00001) and from 84 +/- 11 to 118 +/- 15 beat/min with exercise testing (p = 0.00001). The systolic blood pressure increased from 116 +/- 9 to 138 +/- 11 mmHg with dobutamine (p = 0.00001) and from 117 +/- 8 to 156 +/- 7 mmHg with exercise testing (p = 0.00001). Due to different reasons 33 patients did not finish the exercise protocol, while only 8 patients did not finish the dobutamine testing. The ST segment wast elevated in 22 cases with dobutamine and in 9 cases with exercise, eight of them coinciding in both tests. The ST segment was depressed in 36 cases with dobutamine and in 21 cases with exercise, 20 of them coinciding in both tests. Angina was present in 11 cases with dobutamine and in four exercise, three of them coinciding. If the unfinished tests or those with angina or ST segment depression are considered abnormal, there were 40 abnormal tests with dobutamine and 38 with exercise, 32 of them coinciding.(ABSTRACT TRUNCATED AT 250 WORDS)     

Painless myocardial ischemia in diabetic patients with coronary artery disease: evaluations by treadmill exercise tests

To elucidate the prevalence and features of painless myocardial ischemia among diabetic patients, 44 consecutive patients with angiographically-documented coronary artery disease and positive treadmill tests were examined. They were 26 with diabetes and 18 without it. Painless myocardial ischemia was defined as the absence of chest pain with 1 mm or more ST segment depression during the exercise stress tests. The severity of ischemia was determined by the magnitude of the ST segment depression. Painless myocardial ischemia was observed in 18 of the 26 (69%) diabetics, and in three of the 18 (17%) non-diabetics (p less than 0.005). The frequency of painless ischemia in the diabetics was relatively high regardless of the severity of ischemia, while painless ischemia was less frequent in the non-diabetics with severe ischemia. With a level of 2.5 mm ST depression, 11 of 12 (92%) diabetics were free of pain compared to four of 11 (36%) non-diabetics (p less than 0.01). Absence of chest pain during the exercise tests was not concordant with prior angina in diabetics, as opposed to non-diabetics in whom both clinical and exercise-induced angina developed concordantly. The diabetic patients without chest pain had a higher prevalence of three major diabetic complications such as neuropathy, nephropathy and retinopathy compared to those developing chest pain (p less than 0.025). It was concluded that in diabetics, painless myocardial ischemia is frequently observed during exercise stress tests and its prevalence is relatively high regardless of the severity of ischemia.(ABSTRACT TRUNCATED AT 250 WORDS)     

活动平板运动试验诱发ST段抬高的临床意义

为探讨活动平板运动试验诱发ST段抬高的临床意义 ,分析了 9例无心肌梗死 (简称心梗 )而运动诱发ST段抬高的静息心电图、运动试验及冠状动脉 (简称冠脉 )造影检查结果。结果 :5 0 5 5例行平板运动试验者中 ,有 11例未患心肌梗死而运动诱发心绞痛伴ST段抬高 ,发生率 0 .2 2 %。其中 ,8例患者作了进一步检查 ,冠脉造影显示均有程度不等的血管病变 ,缺血相关血管的狭窄达到 5 0 %～ 10 0 %。ST段抬高导联与缺血相关血管有良好对应关系。另有 1例患者于运动试验 1周后死于心脏性猝死。结论 :无心梗患者运动诱发心电图ST段抬高是冠脉痉挛或冠脉严重狭窄所致心肌局部缺血的标志。     

Clinical presentation and prognosis of left main coronary artery disease in the 1980s

Clinical presentation and course were studied in 127 consecutive patients with angiographically proven left main coronary artery disease. Mean age was 62 (37-79) years. Thirteen patients (10%) had no history of chest pain, seven (5%) had atypical chest pain, and the remaining 107 (85%) typical angina pectoris. Eighty-two patients (65%) had unstable angina, 73 had suffered a myocardial infarction (MI) in the past, and 50 (68%) had post MI angina pectoris. The electrocardiogram was analysed in 102/125 patients during an episode of chest pain and also when they were without chest pain. Outside an episode of chest pain the ST segment was normal in 42 patients (32%), the T wave was normal in 50 patients (38%) and both the ST and T were normal in 33 patients (25%). During chest pain all patients had an abnormal ECG, the most frequent pattern being ST segment depression in leads V3, V4 and V5 (with maximal depression in V4), and ST segment elevation in leads V1 and aVR. The average number of leads with ST-T abnormalities was 6.4. A symptom-limited exercise test on a treadmill with 12-lead ECG monitoring was performed in 89 patients. The exercise test was abnormal in 88 patients (99%), most of whom (74 patients) were already in the first or second stage of the Bruce protocol. The most frequently observed abnormality was ST segment depression of 2 mm or more in leads V4, V5, and V6, and ST segment elevation in leads V1 and aVR. The systolic blood pressure during exercise fell or remained at the same level in 38 patients (43%).(ABSTRACT TRUNCATED AT 250 WORDS)     

Accuracy of the Master's exercise test in detecting significant coronary artery disease

To assess the significance and accuracy of noninvasive tests in detecting significant coronary artery disease (CAD; greater than 50% stenosis), the Master's exercise test, treadmill exercise test and dipyridamole-loading myocardial perfusion scintigraphy were performed and their results were compared with coronary angiographic findings in 60 patients with angina but without myocardial infarction. Among these, 27 patients had significant CAD. The Master's test performed in outpatient clinics had an 85% sensitivity and a 76% specificity in detecting significant CAD, when the degree of ST depression was equal to or exceeded 1 mm. The sensitivity further improved to 96% by adding chest pain to the criteria; then all patients with multivessel disease or critical ischemia were identified by the Master's test. Treadmill tests performed after admission had a 78% sensitivity and a 67% specificity. When the severity of ischemia was judged either by exercise capacity or the degree of ST depression or the coronary T wave, the treadmill test was superior to the Master's test. Although patients without significant CAD had longer exercise capacity and the higher maximum heart rate in the treadmill test than did those in the Master's test, these trends were similar but less marked in patients with significant CAD. Dipyridamole-loading myocardial perfusion scintigraphy showed an excellent sensitivity and specificity; 96% and 94%, respectively, in detecting significant CAD. It was particularly useful in distinguishing false positive exercise results due to left ventricular hypertrophy and coronary spasm and that in women, from true positive results. In conclusion, the Master's test is a simple and useful method for screening CAD in community hospitals and in outpatient clinics.