Painful versus silent myocardial ischemia during leg and arm exercise testing in stable angina pectoris

When 51 patients with proven coronary heart disease and stable angina pectoris underwent exercise testing, 22 experienced painful myocardial ischemia during both leg and arm exercise testing (group L + A), whereas 29 patients had such episodes only during the leg testing (group L). Upright bicycle exercise was performed with the legs first, followed 2 days later by arm testing. Exercise was stopped when typical anginal pain and greater than 1-mm ST horizontal depression occurred during leg testing, and when greater than 1-mm ST horizontal depression was noted during arm testing. Heart rate, systolic blood pressure and rate-pressure product for leg and arm testing, either at the beginning of anginal pain or at the time when 1-mm ST depression was noted, were similar. Two-dimensional echocardiography showed that the L group had higher (p less than 0.01) end-systolic volume at rest and decreased (p less than 0.05) ejection fraction during exercise. Coronary angiography showed that the L group had a greater (p less than 0.001) number of patients with 3-vessel disease, a decreased (p less than 0.001) ejection fraction and less patients with 1-vessel disease. In these patients, absence of anginal pain during arm exercise suggests defective segmental transmission of pain sensation related to severe coronary artery disease. Thus, arm testing, in addition to leg testing, seems to be a simple and useful tool for the detection of severe coronary disease.     

Prognostic significance of silent myocardial ischaemia during maximal exercise testing after a first acute myocardial infarction

Clinical, exercise, and angiographic variables, and long-termfollow-up were compared in patients, who, during maximal Bruceexercise testing after a first acute myocardial infarction (AMI),had positive responses to exercise testing (n = 116, 38% of303) with (n % 23, group I) or without (n = 93, group II) angina.Group I patients more often (52 vs 19%, P < 0.001) had ahistory of pre-infarction angina. Group II had a greater proportion(75 vs 52%, P < 0.05) of inferior wall AMI, whereas groupI had a greater proportion (30 vs 19%, P < 0.01) of non-Qwave AMI. Total exercise duration was significantly (P <0.01) longer in group II (7.6 ± 3.2 vs 5.5 ± 3.1min). Maximal exercise heart rate (144 ± 22 vs 133 ±21, beats . min^–1 P < 0.05 was also higher in groupII. A greater proportion of group II patients (37 vs 9%, P <0.05) had single-vessel disease, whereas multivessel diseasewas more common (91 vs 63% P < 0.03) in group I. Left ventricularfunction was similar in both groups. During follow-up (48 ±22 months) the incidence of cardiac death (group I, 3.3%, groupII, 4.8%), of recurrent infarction (group I, 4.8%, group II3.3%), and of revascularization procedures (group I, 28.5%,group II, 19.8%) were similar in both groups. Although asymptomaticexercise-induced ischaemia was associated with better exerciseperformance and less extensive coronary disease than symptomaticischaemia, it had the same long-term prognostic implications.     

Electrocardiographically and symptomatically silent myocardial ischemia during exercise testing

Certain patients with coronary artery disease (CAD) may have neither ST depression nor chest pain during exercise despite the presence of myocardial ischemia. The frequency and characteristics of such electrocardiographically and symptomatically silent ischemia were studied in 171 patients with both angiographically documented CAD and scintigraphically documented ischemia. Fifty-six (33%) of 171 patients had neither ST depression nor chest pain (Group N), and 115 (67%) had ST depression and/or chest pain (Group P). The two groups were similar with respect to age, gender, the prevalence of prior infarction, and peak systolic blood pressure. Group N patients, however, had a higher mean peak heart rate and rate-pressure product, less severe scintigraphic ischemia, a lower lung thallium-201 uptake, and a smaller number of diseased vessels. Stepwise discriminant analysis showed a history of effort angina, lung thallium-201 uptake, and scintigraphic severity of ischemia to be significant discriminators between Groups N and P. In conclusion, electrocardiographically and symptomatically silent ischemia may be common during exercise in patients with CAD, and less severe ischemia may be one of important determinants.     

Prevalence of silent myocardial ischaemia during exercise stress testing. Its relation to effort tolerance and myocardial perfusion abnormalities.

The number of underperfused myocardial segments, the extent of coronary artery disease and the severity of impairment of coronary flow reserve were compared in 147 consecutive patients exhibiting painful or painless ischaemic ST segment depression on exercise testing. Of 147 patients, only 61 (41%) experienced angina (group 1) whilst 86 (59%) did not (group 2). In the two groups coronary disease was comparable for both extent and distribution, and neither the location of transient perfusion defects nor their relation to areas of old myocardial necrosis appeared to influence the presence or absence of chest pain. However, exercise duration, exercise time and rate-pressure product at the beginning of ischaemia were lower in group 1. Furthermore, a greater proportion of asymptomatic patients had only one ischaemic segment on 99mTc-MIBI perfusion scintigraphy. We conclude that: (1) in patients with effort angina and coronary disease, the incidence of electrocardiographic silent ischaemic events induced by exercise is similar to that observed in studies based on continuous ECG monitoring. (2) Exertional angina is more frequently associated with greater ischaemic areas and with more severe degrees of impairment of residual coronary flow reserve. (3) The presence of an old myocardial infarction does not appear to influence the incidence of ischaemic cardiac pain.     

Haemodynamic changes during silent myocardial ischaemia

The haemodynamic significance of asymptomatic ST segment depression has been assessed in patients with coronary artery disease by direct measurement of left ventricular end-diastolic pressure (LVEDP) or pulmonary artery end-diastolic pressure (PADP). Both techniques have demonstrated a rise in pressure during such episodes of ST segment depression recorded in the Coronary Care Unit, cardiac catheter and exercise laboratories or during ambulant activity. Thus silent or asymptomatic ST segment depression is associated with similar haemodynamic changes to that seen during angina pectoris and has considerable therapeutic implications.     

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.     

Percutaneous transluminal coronary angioplasty in patients with silent myocardial ischemia during exercise testing

Silent myocardial ischemia was present in 50 of 507 patients undergoing PTCA. Of these patients, five had type 1 (asymptomatic with no previous myocardial infarction), 27 had type 2 (asymptomatic after myocardial infarction) and 18 had type 3 silent myocardial ischemia (angina present in addition to silent episodes). Ischemia was documented in all patients in the exercise ECG, in 18 patients with thallium scintigraphy and in four with radionuclide ventriculography. The indication for PTCA was considered established in patients with type 1 silent ischemia based on ECG changes in the presence of high grade stenosis of the left anterior descending artery under the assumption of improved prognosis. The fact that patients with myocardial infarction have a poorer prognosis in the presence of ST-segment depression served as the basis for the indication for PTCA in type 2 patients. In type 3 patients, PTCA was carried out to ameliorate the symptomatic as well as asymptomatic episodes of ischemia. The follow-up period averaged 12 +/- 6 months. The primary rate of success was 92% with no differences between the groups. There were no complications in type 1 and type 2 patients; in two patients with type 3 silent ischemia, immediate bypass surgery was carried out due to acute occlusion of the dilated vessel. One patient in the latter group had myocardial infarction in the region perfused by the dilated vessel four months after the procedure. The angiographically-documented rate of restenosis was 33% in type 1 patients, 26% in type 2 and 40% in type 3 patients.(ABSTRACT TRUNCATED AT 250 WORDS)     

Exercise-induced myocardial ischaemia detected by cardiopulmonary exercise testing.

BACKGROUND: The objective of the study was to identify the parameter(s) of cardiopulmonary exercise testing (CPET) that can detect exercise-induced myocardial ischaemia (EIMI), and to determine its diagnostic accuracy for identifying patients with coronary artery disease (CAD). METHODS AND RESULTS: We prospectively studied 202 consecutive patients (173 men, 29 women, mean age 55.7+/-10.8 years) with documented CAD. All patients underwent an incremental exercise stress testing (ECG-St) with breath-by-breath gas exchange analysis, followed by a 2-day stress/rest gated SPECT myocardial scintigraphy (GSMS) as the gold standard for ischaemia detection. ROC analysis selected a two-variable model-O(2)pulse flattening duration, calculated from the onset of myocardial ischaemia to peak exercise, and deltaVO(2)/deltawork rate slope-to predict EIMI by CPET. GSMS identified 140 patients with reversible myocardial defects, with a Summed Difference Score (SDS) of 9.7+/-2.8, and excluded EIMI in 62 (SDS 1.3+/-1.6). ECG-St had low sensitivity (46%) and specificity (66%) to diagnose EIMI as compared with CPET (87% and 74%, respectively). CONCLUSIONS: The addition of gas exchange analysis improves the diagnostic accuracy of standard ECG stress testing in identifying EIMI. A two-variable model based on O(2)pulse flattening duration and deltaVO(2)/deltawork rate slope had the highest predictive ability to identify EIMI.     

Significance of silent myocardial ischemia during exercise testing in patients with coronary artery disease

To evaluate the significance of ischemic ST-segment depression without associated chest pain during exercise testing, data were analyzed from 2,982 patients from the Coronary Artery Surgery Study (CASS) registry who underwent coronary arteriography and exercise testing and were followed up for 7 years. Patients with proved coronary artery disease (CAD) (at least 70% diameter narrowing) were grouped according to whether they had at least 1 mm of ST-segment depression or anginal chest pain during exercise testing. Four hundred twenty-four had ischemic ST depression without angina (group 1); 232 had angina but no ischemic ST depression (group 2); 456 had both ischemic ST depression and angina (group 3); and 471 had neither ischemic ST depression nor angina (group 4). Sixty-three percent of patients in group 1 and 55% in group 2 had multivessel CAD (difference not significant). The 7-year survival rates were similar for patients in groups 1 (76%), 2 (77%), and 3 (78%), but were significantly better for patients in group 4 (88%, p less than 0.001). Among group 1 patients, survival was related to severity of CAD (p less than 0.001). The 7-year survival rate in group 1 was significantly worse than that in a separate group of 282 patients with ischemic ST depression without angina during exercise testing who had no CAD (95% survival, p less than 0.001). Thus, in patients with silent myocardial ischemia during exercise testing, the extent of CAD and the 7-year survival rate are similar to those of patients with angina during exercise testing. Prognosis is determined primarily by the severity of CAD. In patients without CAD, the survival rate is excellent.     

Amlodipine reduces myocardial ischaemia during exercise without compromising left ventricular function in patients with silent ischaemia: a randomised, double-blind, placebo-controlled study

BACKGROUND: Left ventricular systolic function is reduced during episodes of silent ischaemia in patients with coronary artery disease (CAD). In most normal subjects left ventricular ejection fraction (LVEF) increases at least 5% during exercise whereas LVEF often remains unchanged or decreases in patients with CAD. The anti-ischaemic effect of calcium antagonists is well documented including a capability to reduce exercise-induced electrocardiographic ST-depressions, whereas the effect of these drugs on LV volume changes during exercise in patients with silent ischaemia is unknown. AIM: The aim of this study was to evaluate the effect of amlodipine on rest and exercise LVEF in patients with silent ischaemia. METHODS: Twenty-one patients completed a double-blind placebo-controlled cross-over study. Conventional exercise test and radionuclide cardiographies during exercise were used for determining haemodynamic parameters. RESULTS: Exercise-induced electrocardiographic ST-depressions were reduced in 83% of the patients having ST-deviations during placebo even though 10 patients were already treated with a beta-blocker. Amlodipine did not affect left ventricular systolic function compared to placebo, neither at rest nor during exercise. CONCLUSION: The results indicated that amlodipine is a safe anti-ischaemic drug in patients with silent ischaemia concerning cardiac function.     

Comparison of silent and symptomatic ischemia during exercise testing in men

OBJECTIVE: To compare angina and ST-segment depression during exercise testing, as markers for coronary artery disease. DESIGN: Retrospective analysis of exercise test responses and cardiac catheterization results. SETTING: A U.S. Veterans Affairs medical center. PATIENTS: Four hundred and sixteen men who were referred for the evaluation of symptoms, postmyocardial infarction testing, or both. Two hundred patients had no clinical or electrocardiographic evidence of previous myocardial infarction, whereas 216 were survivors of a previous myocardial infarction. INTERVENTIONS: All patients did a standard exercise test and had diagnostic coronary angiography with ventriculography within an average of 32 days (range, 0 to 90 days) of their exercise test. RESULTS: Two hundred patients without a previous myocardial infarction were divided into four groups: the no ischemia group had 80 patients; the angina pectoris only group had 23 patients; the silent ischemia group had 40 patients; and the ST-segment depression and angina pectoris group had 57 patients. In patients without a previous myocardial infarction, exercise-induced ST-segment depression was a better marker than exercise-induced angina for the presence of any coronary artery disease (P less than 0.005). Patients with symptomatic exercise-induced ischemia had a higher prevalence of severe coronary artery disease than did those with only silent ischemia (30% compared with 20%; 95% CI, - 7.3% to 27.0%; P = 0.005). For the 216 survivors of a myocardial infarction, divided into the same four groups, ST-segment depression again was a better marker for the presence of severe coronary artery disease compared with angina alone (P = 0.08). The prevalence rates of severe coronary artery disease in the no ischemia plus myocardial infarction group, the angina pectoris only plus myocardial infarction group, the silent ischemia plus myocardial infarction group, and the ST-segment depression and angina pectoris plus myocardial infarction group were 10%, 9%, 23%, and 32%, respectively (P less than 0.01). CONCLUSIONS: Exercise-induced ST-segment depression is a better marker for coronary artery disease than is exercise-induced angina. Symptomatic ischemia during the exercise test is a better marker for severe coronary artery disease than is silent ischemia.     

Risk factors and their implication on silent myocardial ischaemia

Sixty-five cases were evaluated for silent myocardial ischaemia (SMI) by computerised treadmill test (TMT) and ambulatory electrocardiographic monitoring (AEM). There were 59 males and 6 females. The cases were divided into GP-I-stable angina (35 cases) GP-II-stable angina after myocardial infarction (15 cases) and GP-III-asymptomatic (15 cases). Age in each group ranged from 36 years to 62 years (GP-I), 40 years to 68 years (GP-II) and 36 years to 48 years (GP-III). Conventional risk factors viz. hypertension, diabetes mellitus, hyperlipidemia, smoking and family history were assessed with a view to see their implication on SMI. 43 patients (62.2%) were found to have SMI including mixed episodes. Out of these 43, TMT was positive in 29 patients (67.4%), AEM was positive in 41 patients (95.3%) and both TMT and AEM were positive in 27 patients (62.7%). Correlative analysis between risk factors and SMI revealed that higher number of was associated with not only more positive TMT and AEM test along with increased episodes of SMI but also increased degree of ST-T depression. It was also found that AEM is more sensitive than TMT (80% Vs 48%) for diagnosing SMI (SED = 9.03%), though specificity of the tests is same (93.3%).     

Prevalence and prognostic significance of silent myocardial ischaemia detected by exercise test and continuous ECG monitoring after acute myocardial infarction

The incidence and prognostic significance of silent myocardial ischaemia in 165 patients who survived a first acute myocardial infarction were assessed by means of maximal exercise stress test and 24 h continuous ECG monitoring performed before discharge. During the 1 year follow-up period 10 cardiac deaths occurred; moreover seven patients suffered a fatal myocardial re-infarction and 14 developed unstable angina. Cardiac death occurred in five of 40 patients (12.5%) with ST segment depression on stress test by in only three of 117 (2.6%) without ST segment changes (P less than 0.01). One-hundred-and-three of 117 patients (88.0%) without angina or ST segment depression on stress testing survived 1 year without cardiac events, compared with 24 of 40 patients (60.0%) with ST segment depression whether or not associated with angina (P less than 0.001). Cardiac death occurred in five of 25 patients (20.0%) with ST segment depression on continuous ECG monitoring, compared with five of 140 (3.6%) without (P less than 0.01). One-hundred-and-seventeen out of 140 patients (83.6%) without angina or ST segment depression survived 1 year follow-up without cardiac events, compared with 13 of 25 (52.0%) with ST segment depression with or without angina (P less than 0.01). Classifying patients in a 2 x 5 contingency table according to the occurrence of ST segment depression on exercise testing and/or ECG ambulatory monitoring, the Yates corrected chi-square test showed a significant pattern when cardiac deaths and cardiac events were considered together (P less than 0.01).(ABSTRACT TRUNCATED AT 250 WORDS)     

Use of dobutamine stress echocardiography in detecting silent myocardial ischaemia in asymptomatic diabetic patients: a comparison with thallium scintigraphy and exercise testing.

AIMS: Silent myocardial ischaemia is frequent in diabetic patients. The aim of this study was to compare the efficacy of thallium-201 single-photon emission computed tomography (201Tl SPECT) coupled with exercise stress testing (EST), and dobutamine stress echocardiography (DSE) in the detection of asymptomatic coronary artery disease. METHODS: Fifty-six asymptomatic diabetic patients, with a known duration of diabetes > 15 years for Type 1 and > 5 years for Type 2, having at least three added risk factors, but without rest ECG abnormalities, were enrolled in this prospective study. All of them were submitted to DSE with a maximum infusion rate of 40 microg/kg per min dobutamine +/- i.v. atropine, and to 201Tl SPECT coupled with EST. Coronary angiography was performed if at least one test was abnormal. RESULTS: Diabetic patients were 37 males and 19 females, aged mean (sd) 60 +/- 10 years, 10 Type 1 and 46 Type 2, with a known duration of disease of mean (sd) 17 +/- 9 years. Feasibility of DSE was 91%. No serious complication occurred during the test. Coronary angiography was performed in 26 patients (47%); 17 were abnormal (30% of the whole group): six patients had a one-vessel, six a two-vessel and five a three-vessel disease. Predictive positive value was 69% for DSE, 75% for 201Tl SPECT and 60% for EST. DSE was falsely negative in four cases vs. eight for 201Tl SPECT and nine for EST. CONCLUSIONS: Asymptomatic coronary disease is common in diabetes associated with other risk factors. DSE appears useful in its detection and a good alternative to 201Tl SPECT.     

Usefulness of exercise testing performed with vasodilators for predicting the severity of myocardial ischaemia during daily activities and treatment

Fifty patients (aged 53±7 years) with confirmed coronarydisease performed two stress tests (baseline and following treatmentwith vasodilators) and were divided into two groups. (A) fixedischaemic threshold (n = 27), and (B) variable ischaemic threshold(n = 23). All patients underwent 24-h baseline Holter monitoringand monitoring following treatment with nifedipine, placebo,propranolol and nifedipine + propranolol. In Group A, 92% of ischaemic episodes occurred at heart ratessimilar to those found during exercise testing. In Group B,the heart rate was lower in 66%. In Group A, positive stresstesting before the first 3 min of exercise, or at < 140 beat.min^–1 with ST segment depressions 0.02 mV, correlatedwith higher Holter indexes. In Group A, propranolol reducedboth the number of episodes and total ischaemia time. In GroupB, the best effects were achieved with nifedipine and combinedtreatment. Our results further emphasize the contrasts between patientswith angina and fixed and variable ischaemic thresholds andsuggest that therapy tailored to the physiopathology may bemost efficacious.     

Prevalence of and variables associated with silent myocardial ischemia on exercise thallium-201 stress testing

The prevalence of silent myocardial ischemia was prospectively assessed in a group of 103 consecutive patients (mean age 59 +/- 10 years, 79% male) undergoing symptom-limited exercise thallium-201 scintigraphy. Variables that best correlated with the occurrence of painless ischemia by quantitative scintigraphic criteria were examined. Fifty-nine patients (57%) had no angina on exercise testing. A significantly greater percent of patients with silent ischemia than of patients with angina had a recent myocardial infarction (31% versus 7%, p less than 0.01), had no prior angina (91% versus 64%, p less than 0.01), had dyspnea as an exercise test end point (56% versus 35%, p less than 0.05) and exhibited redistribution defects in the supply regions of the right and circumflex coronary arteries (50% versus 35%, p less than 0.05). The group with exercise angina had more ST depression (64% versus 41%, p less than 0.05) and more patients with four or more redistribution defects. However, there was no difference between the two groups with respect to mean total thallium-201 perfusion score, number of redistribution defects per patient, multi-vessel thallium redistribution pattern or extent of angiographic coronary artery disease. There was also no difference between the silent ischemia and angina groups with respect to antianginal drug usage, prevalence of diabetes mellitus, exercise duration, peak exercise heart rate, peak work load, peak double (rate-pressure) product and percent of patients achieving greater than or equal to 85% of maximal predicted heart rate for age. Thus, in this study group, there was a rather high prevalence rate of silent ischemia (57%) by exercise thallium-201 criteria.(ABSTRACT TRUNCATED AT 250 WORDS)     

The role of exercise testing in the identification of patients with silent myocardial ischemia

At present, the role of exercise testing in asymptomatic individuals is limited, and the test should be applied only selectively. Regardless of this, the popularity of wellness programs and the widespread use of exercise testing in asymptomatic groups continue. The preceding discussion presents some guidelines to help improve on the diagnostic accuracy of exercise testing in all patients, with special emphasis on its use in asymptomatic individuals.