Negative Exercise Electrocardiogram Research Articles

Exercise electrocardiogram testing in asymptomatic patient with type 2 diabetes and left ventricular diastolic dysfunction

Background: Type 2 diabetes mellitus (DM) is an established risk factor for cardiovascular events and the development of congestive heart failure (HF). Diastolic dysfunction is considered a precursor of HF and may be diagnosed noninvasively by echocardiography. Diastolic dysfunction is common in well-controlled type 2 diabetic patients without clinically detectable heart disease. Left ventricular diastolic dysfunction represents the earliest preclinical dysfunction and that it can progress to asymptomatic HF. Aim of the Work: The aim of the study is to evaluate if diastolic dysfunction in diabetic patients is due to silent ischemia. Methods: This study included 80 asymptomatic patients with type 2 DM. Echocardiography was done to all patients to assess systolic and diastolic functions. Exercise electrocardiogram (ECG) was done for all patients to detect ischemic heart disease. Coronary angiography was done to patients with positive exercise ECG test. Results: The incidence of diastolic dysfunction was 75%; among the studied groups. Impaired relaxation was detected in 87 % and pseudo normal pattern was detected in 13 % of subjects with diastolic dysfunction. Patients with normal diastolic function had negative stress exercise test, while those with diastolic dysfunction, 12 patients had positive exercise stress ECG (40%) and 18 patients had negative exercise stress ECG (60%). Conclusion: These findings indicate that coronary artery disease is not uncommon in diabetic patients with diastolic dysfunction and increase markedly in patients with positive stress exercise electrocardiography.

Exercise Electrocardiogram Neither Predicts Nor Excludes Coronary Artery Disease in Women with Low to Intermediate Risk.

The value of exercise electrocardiogram (ExECG) in symptomatic female patients with low to intermediate risk for significant coronary artery disease (CAD) has been under debate for many years, and nondiagnostic or even erroneous test results are frequently encountered. Cardiac-CT may be more appropriate to exclude CAD in women. This study compares the results of ExECGs with those of cardiac-CTs, performed within a time frame of 1 month in an all-comers female chest pain population. Five hundred fifty-one consecutive female patients from a patient registry were included. ExECGs were negative in 324 (59%), positive in 14 (3%), and nondiagnostic in 213 (39%) patients. CAD was revealed by cardiac-CT in 57% of the women with negative ExECG. No signs of CAD were present on cardiac-CT in 64% of the women with a positive ExECG. Cardiac-CT showed presence of CAD in 268/551 (49%) patients, of whom 56/268 (21%) was diagnosed with ≥50% stenosis. The ExECG of the latter group was negative in 26 (46%), inconclusive in 29 (52%), and positive in 1 (2%). Considering ≥50% stenosis at cardiac-CT as the reference, sensitivity, specificity, PPV, and NPV of ExECG for the present population were 3.7%, 95.7%, 7.1%, and 91.7%, respectively. Similar diagnostic performance was calculated when considering ≥70% stenosis at cardiac-CT as the reference. ExECG failed to detect CAD in more than half of this cohort and in almost half of women with >50% stenosis at cardiac-CT. Importantly, no CAD was detected by cardiac-CT in 64% of women with a positive ExECG. ExECG is therefore questionable as a diagnostic strategy in women with low-to-intermediate risk of CAD, although prospective studies are warranted to determine whether replacing ExECG by cardiac-CT provides better prognoses.

Exercise electrocardiogram testing in two brothers with different outcome – a case study exercise testing in master cyclists

The cases of two brothers training and competing as master cyclists and both preparing for a cycling tour are presented. The older brother aged 66 years went first to the primary care physician and presented with an asymptomatic depression in the exercise stress test of the ST segment in V5 and V6 during recovery after complete exhaustion. Coronary angiography revealed a multi vessel coronary artery disease and he underwent bypass surgery. One year later, he successfully completed his planned cycling tour of ~600 km in seven stages and covering ~12,000 m of total ascent. The younger brother aged 59 years went a few months later to the primary care physician and also performed asymptomatic exercise stress testing without changes in the ST segments. Unfortunately, 2 months later he suffered a cardiac arrest during his cycling tour and survived following immediate successful cardiopulmonary resuscitation on the road by his cycling colleagues. Immediate invasive coronary arteriography showed a complete stenosis of the trunk of arteria coronaria sinistra (left coronary artery), a 40%–50% stenosis of ramus circumflexus, and a 20% stenosis of arteria coronaria dextra (right coronary artery). The left coronary artery was dilated and he continued cycling 2 months later. In both brothers, familial hypercholesterolemia was the main cardiovascular risk factor for the multi vessel coronary artery disease. A negative exercise electrocardiogram in siblings with an increased risk for coronary artery disease seemed not to exclude an advanced multi vessel coronary artery disease. In master athletes with asymptomatic exercise electrocardiogram but a positive family history, further examinations should be performed in order to detect relevant stenosis in coronary arteries.

Risk scores prognostic implementation in patients with chest pain and nondiagnostic electrocardiograms

BackgroundSeveral risk scores are available for prognostic purpose in patients presenting with chest pain. AimThe aim of this study was to compare Grace, Pursuit, Thrombolysis in Myocardial Infarction (TIMI), Goldman, Sanchis, and Florence Prediction Rule (FPR) to exercise electrocardiogram (ECG), decision making, and outcome in the emergency setting. MethodsPatients with nondiagnostic ECGs and normal troponins and without history of coronary disease underwent exercise ECG. Patients with positive testing underwent coronary angiography; otherwise, they were discharged.End point was the composite of coronary stenosis at angiography or cardiovascular death, myocardial infarction, angina, and revascularization at 12-month follow-up. ResultsOf 508 patients considered, 320 had no history of coronary disease: 29 were unable to perform exercise testing, and finally, 291 were enrolled. Areas under the receiver operating characteristic curves for Grace, Pursuit, TIMI, Goldman, Sanchis, and FPR were 0.59, 0.68, 0.69, 0.543, 0.66, and 0.74, respectively (P < .05 FPR vs Goldman and Grace). In patients with negative exercise ECG and overall low risk score, only the FPR effectively succeeded in recognizing those who achieved the end point; in patients with high risk score, the additional presence of carotid stenosis and recurrent angina predicted the end point (odds ratio, 12 and 5, respectively). Overall, logistic regression analysis including exercise ECG, coronary risk factors, and risk scores showed that exercise ECG was an independent predictor of coronary events (P < .001). ConclusionsThe FPR effectively succeeds in ruling out coronary events in patients categorized with overall low risk score. Exercise ECG, nonetheless being an independent predictor of coronary events could be considered questionable in this subset of patients.

Resting Chest Pain, Negative Treadmill Exercise Electrocardiogram, and Reverse Redistribution in Dipyridamole Myocardial Perfusion Scintigraphy Might be the Features of Coronary Artery Spasm

Coronary artery spasm usually attacks while at rest and the diagnosis depends on provoking tests which mostly are invasive, expensive and not practical. Previous investigations demonstrated that in most patients with coronary artery spasm, treadmill exercise electrocardiography (TEEC) did not induce any ischemic changes, and myocardial perfusion scintigraphy (MPS) showed reverse redistribution (RR). Combination of resting chest pain, negative TEEC and RR might be a rational noninvasive set to predict coronary artery spasm. Patients with chest pain at rest, no significant coronary artery stenosis, and willing to undergo acetylcholine test were included. TEEC, dipyridamole and rest thallium-201 MPS were performed before or after coronary angiography. The patients were divided into spasm and nonspasm groups by acetylcholine test. The clinical features and results of TEEC and MPS were compared between the spasm and nonspasm groups. Acetylcholine test was performed in 92 patients and coronary artery spasm was successfully provoked in 68 patients. Positive TEEC was induced in only 4 patients in the spasm group. RR was present in totally 77 patients and 68 of them were from the spasm group. By a combination of resting chest pain, negative TEEC and RR to diagnose coronary artery spasm, the sensitivity and specificity were 94% and 96% respectively. Combination of resting chest pain, negative TEE and RR appears to be a rational noninvasive set to predict coronary artery spasm.

Comparison of the Prognostic Value of the Stress-Recovery Index Versus Standard Electrocardiographic Criteria in Patients With a Negative Exercise Electrocardiogram

To verify whether the stress recovery index (SRI) improves risk stratification in patients with a negative exercise electrocardiogram (ECG) using standard criteria, the SRI was derived in 708 consecutive patients with a negative exercise ECG. All-cause mortality and the combination of death or nonfatal myocardial infarction were target end points. The individual effect of clinical and exercise testing data on outcome was evaluated using Cox regression analysis with separate models for each group of variables. Model validation was performed using bootstrap adjusted by degree of optimism in estimates. Survival analysis was performed using a product-limit Kaplan-Meier method. During a 37-month follow-up, 22 deaths and 40 nonfatal acute coronary syndromes occurred. After adjusting for confounding variables, age (hazard ratio 1.62, 95% confidence interval [CI] 1.14 to 2.31 for interquartile difference), hypertension (hazard ratio 1.74, 95% CI 1.04 to 2.89), and SRI (hazard ratio 0.75, 95% CI 0.65 to 0.86 for interquartile difference) were predictive of death or nonfatal myocardial infarction. Moreover, SRI increased the prognostic power of the model on top of clinical and exercise testing variables and provided significant discrimination of survival. In conclusion, the SRI may help refine the prognostic stratification of patients with a negative exercise test result using standard electrocardiographic criteria.

Diagnostic work-up of unselected patients with suspected coronary artery disease: complementary role of multidetector computed tomography, symptoms and electrocardiogram stress test

We evaluated the accuracy of multidetector computed tomography in detecting coronary artery disease and how it could change the indication to coronary angiography in patients with suspected cardiac chest pain. We enrolled 142 consecutive patients who had already performed an exercise electrocardiogram test referred to our hospital and scheduled for coronary angiography for chest pain. According to the characteristics of chest pain and the results of exercise electrocardiogram, patients were divided into four groups: atypical chest pain and negative exercise electrocardiogram (group 1); typical chest pain and negative exercise electrocardiogram (group 2); atypical chest pain and positive exercise electrocardiogram (group 3); and typical chest pain with positive exercise electrocardiogram (group 4). We evaluated the accuracy of multidetector computed tomography and whether it could reduce the number of unnecessary coronary angiography in the study groups. Of 1801 segments larger than 1.5 mm, 1696 (94%) were assessable. In a segment based-model, sensitivity, specificity, negative predictive value, positive predictive value and accuracy were 81% (95% confidence interval 75-89%), 94% (95% confidence interval 90-98%), 96% (95% confidence interval 93-98%), 75% (95% confidence interval 69-82%) and 91% (95% confidence interval 89-93%), respectively. In a patient-based model, sensitivity, specificity, negative predictive value, positive predictive value and accuracy were 95% (95% confidence interval 91-99%), 78% (95% confidence interval 67-89%), 88% (95% confidence interval 79-97%), 89% (95% confidence interval 83-95%) and 89% (95% confidence interval 84-94%). Unnecessary coronary angiography may be avoided by multidetector computed tomography results particularly in group 2 (16%) and group 3 (24%), whereas in groups 1 and 4 the role of multidetector computed tomography in facilitating the correct indication to coronary angiography was less relevant. Multidetector computed tomography is a particularly helpful technique in patients with discordance between the clinical features of chest pain and stress-test results. This technique may be introduced in the diagnostic work-up of patients with suspected coronary artery disease and may potentially reduce the number of unnecessary coronary angiography.

Immediate exercise testing of low risk patients with known coronary artery disease presenting to the emergency department with chest pain

OBJECTIVESThe purpose of this study was to demonstrate the safety and utility of immediate exercise treadmill testing (IETT) of low risk patients presenting to the emergency department with known coronary artery disease (CAD).BACKGROUNDMore than 70% of the two million patients admitted to U.S. hospitals annually for suspected acute myocardial infarction (AMI) are found not to have had a cardiac event. We have previously demonstrated the safety and efficacy of IETT of selected low risk patients without known CAD presenting to the emergency department with chest pain. This study extends this approach to selected patients with a history of CAD.METHODSOne hundred patients evaluated by the chest pain emergency room to rule out AMI underwent IETT using a modified Bruce protocol upon admission to the hospital (median time <1 h).RESULTSTwenty-three patients (23%) had positive exercise electrocardiograms (ExECGs); an uncomplicated non–Q wave AMI was diagnosed in two patients. Thirty-eight patients (38%) had negative ExECGs and 39 patients (39%) had nondiagnostic ExECGs. Of these 100 patients, 64 were discharged immediately after IETT, 19 were discharged in less than 24 h after negative serial cardiac enzymes and stable electrocardiograms and 17 were discharged after further evaluation and treatment. There were no complications from exercise testing and no late deaths or AMI during six-month follow-up.CONCLUSIONSImmediate exercise treadmill testing of low risk patients with chest pain and known CAD is effective in further stratifying this group into patients who can be safely discharged and those who require hospital admission.

QT dispersion plus ST-segment depression: a new predictor of restenosis after successful percutaneous transluminal coronary angioplasty.

ST-segment depression during exercise testing is frequently observed in the absence of restenosis after percutaneous transluminal coronary angioplasty (PTCA). With the goal of improving the prediction of restenosis after PTCA, we evaluated the usefulness of ST-segment depression plus QT dispersion (QTd = QTmax - QTmin) during treadmill stress test. Fifty-six patients (37 men, 19 women, mean age 51 +/- 14 years) were evaluated with treadmill exercise testing and coronary angiography 7 +/- 5 months after PTCA. Treadmill test was positive in 30 patients and negative in 26 patients. At coronary angiography, restenosis was present in 16 patients with positive exercise electrocardiogram (ECG) and in 6 patients with negative exercise ECG. Fourteen patients with a positive stress test did not have restenosis. There was no difference in QTd values between groups at baseline (p > 0.05). Exercise QTd was 63 +/- 9 ms in patients with positive exercise test, 54 +/- 18 ms in patients with negative exercise test (p = 0.003), 71 +/- 13 ms in patients with restenosis, and 53 +/- 17 ms in patients without restenosis (p = 0.001). ST-segment depression during the stress test determined restenosis with a sensitivity of 80% and a specificity of 58%. Sensitivity and specificity of QTd of > or = 60 ms for prediction of restenosis were 83 and 61%, respectively. When QTd of > or = 60 ms was added to ST-segment depression as a condition for positive test, the sensitivity and specificity increased to 91 and 78%, respectively. QT dispersion plus ST-segment depression had higher sensitivity and specificity than either QTd or ST-segment depression alone (p < 0.05). The addition of QTd to ST-segment depression during exercise test improves the diagnostic value and can be used as a noninvasive tool in the diagnosis of restenosis after PTCA.

Risk stratification of patients with medically treated unstable angina using exercise echocardiography

Functional testing is recommended for risk stratification of medically treated patients with unstable angina. Exercise echocardiography is used in this situation, but its safety and prognostic value are not well defined. The objective of this study was to assess the incremental prognostic value of exercise echocardiography in 226 consecutive patients (128 men, age 59± 13 years) with medically treated unstable angina, who underwent exercise echocardiography from 1991 to 1996. Clinical risk was designated as low in 108 patients, intermediate in 116, and high in 2 patients according to the unstable angina practice guidelines. There were no major complications from the stress tests. The exercise electrocardiogram was nondiagnostic in 57 patients (25%). Ischemia was identified by exercise electrocardiography in 33 patients and exercise echocardiography in 55 patients. Patients were followed for 29 ± 18 months. After exclusion of 38 patients who underwent early revascularization, 28 patients had cardiac death, nonfatal infarction, and late (>3 months) revascularization. Ischemia at exercise echocardiography was associated with a 24-month event-free survival of 81%, compared to 95% with negative exercise echocardiography (p = 0.02). A positive exercise electrocardiogram was associated with a 24-month event-free survival of 84%, compared to 93% with negative exercise electrocardiograms (p = 0.08). In a Cox regression model, event-free survival was predicted by ischemia at exercise echocardiography (relative risk 2.8, confidence interval: 1.3 to 6.3, p = 0.05), but not at exercise electrocardiography (relative risk 2.1, confidence interval 0.7 to 5.8, p = 0.16).

Usefulness of exercise echocardiography in predicting cardiac events in an outpatient population

The prognostic value of exercise echocardiography in an outpatient population is not well defined. A total of 1,020 consecutive patients referred for exercise echocardiography in an ambulatory care setting were studied by reviewing their medical records and exercise echocardiographic data. Of these, 71 (7%) were excluded due to technically inadequate tests, leaving 949 patients who were included in the analysis. A positive exercise echocardiogram (EE) was defined as an appearance of a new wall motion abnormality or worsening of a baseline abnormality. Cardiac events, defined as myocardial infarction, coronary angioplasty, coronary bypass surgery, and death, were documented during a 12-month follow-up period. Cardiac events occurred in 17% of patients (26 of 152) with a positive exercise echocardiogram (EE) and in 2.5% (20 of 797) with a negative EE (p <0.001). The incidence of myocardial infarction (2.6% vs 0.4%, p <0.02), coronary angioplasty (7% vs 1%, p <0.001), and coronary bypass surgery (9% vs 1%, p <0.001) were higher in patients with a positive versus a negative EE. There was 1 death in the positive study group and none in the negative group. Significant independent variables (p <0.05) that predicted cardiac events included a positive exercise electrocardiogram, history of coronary angioplasty, nonspecific ST-T changes on the baseline electrocardiogram, double product <25,000, men, chest pain on exercise test, and a positive exercise electrocardiogram. On a stepwise logistic regression model, exercise echocardiography emerged as an independent predictor of future cardiac events in an outpatient population. This predictive value was enhanced in the presence of a positive exercise electrocardiogram compared with a negative exercise electrocardiogram (24.2% vs 7.9%, p <0.03). Our study suggests that exercise echocardiograhy is an independent predictor of future cardiac events in an outpatient population.

Prognostic Value of Dobutamine Echocardiography Early After Uncomplicated Acute Myocardial Infarction: A Comparison With Exercise Electrocardiography

Objectives. This study sought to assess the relative prognostic power of dobutamine echocardiography and exercise electrocardiography after acute myocardial infarction.Background. The prognostic value of dobutamine echocardiography early after acute myocardial infarction has not yet been reported.Methods. One hundred seventy-eight patients (mean age 58 ± 9 years) with a first uncomplicated acute myocardial infarction underwent predischarge dobutamine echocardiography (5 to 40 μg/kg body weight per min, plus atropine if needed) and symptom-limited bicycle exercise electrocardiography and were followed up for 17 ± 13 months. Stress-induced dyssynergy and ST segment depression >1 mm were considered criteria of positivity for dobutamine echocardiography and exercise electrocardiography, respectively.Results. Dobutamine echocardiography was positive in 83 patients and exercise electrocardiography in 60. At follow-up there were 5 deaths, 6 nonfatal myocardial infarctions (11 hard events) and 20 cases of unstable angina. Dobutamine echocardiography and exercise electrocardiography had similar negative predictive values both for all events (88% and 86%, respectively) and for hard events (98% and 95%, respectively). The hard events rate was significantly higher in patients with positive rather than negative dobutamine echocardiography (relative risk [RR] 5.15, 95% confidence interval [CI] 1.14 to 23.16), although there was no difference between patients with positive and negative exercise electrocardiograms. When Cox analysis was performed, dobutamine echocardiography had an independent prognostic value both for all events (RR 2.88, 95% CI 1.37 to 6.08) and for hard events (RR 6.56, 95% CI 1.42 to 30.46).Conclusions. After uncomplicated acute myocardial infarction, dobutamine echocardiography and exercise electrocardiography have a similar high negative predictive value for both all events and hard events only. Positive dobutamine echocardiography, but not positive exercise electrocardiography, identifies a group of patients at higher risk of subsequent cardiac events.(J Am Coll Cardiol 1997;29:261–7)

The paradox of negative exercise stress ECG/positive thallium scintigram: Ischemic ST-segment counterpoise as the underlying mechanism

A 62-year-old woman with exertional angina underwent an exercise thallium-201 stress test. She exercised for 4 minutes on the treadmill using a modified Bruce protocol, reaching 94% of her predicted maximal heart rate, and stopped because of chest pain and fatigue. No ST-segment depression was detected at peak exercise or in the recovery period. In contrast, the thallium-201 myocardial single-photon emission computed tomography images in the short-axis, vertical long-axis, and horizontal long-axis views revealed severe myocardial ischemia involving the anterior, septal, posteroinferior, and posterolateral planes of the heart. Coronary arteriography showed severe stenosis of the left anterior descending and right coronary arteries. The information from the exercise electrocardiogram (ECG), thallium-201 myocardial scintigraphy, and a coronary angiogram suggested that the false negative ECG response was due to ischemic ST-segment counterpoise (ie, cancelation of ischemic ST-segment vectors, generated by equally extensive and severe ischemia involving myocardial planes opposite each other.

Limited value of stress electrocardiographic changes in predicting late 201Tl reversibility

The aim of this study was to assess the relationship between the exercise electrocardiogram (ECG) and late thallium-201 (201Tl) reversibility in a series of 72 consecutive patients with undiagnosed chest pain and an initial persistent perfusion defect on conventional stress/4-h redistribution imaging. We wished to establish the diagnostic accuracy of the exercise ECG in predicting the outcome of late 201Tl reversibility. All 72 patients, of whom 44 (61%) had had a previous myocardial infarction (MI), underwent quantitative planar 201Tl stress-redistribution imaging followed by resting 201Tl imaging 1-4 days later. Fifty (69%) patients showed exercise ECG changes during conventional stress-redistribution imaging, of whom 30 (42%) had a history of previous MI and 20 (28%) had suspected coronary artery disease (CAD). The overall diagnostic accuracy of the exercise ECG in predicting 201Tl reversibility was 83% (60/72 patients): 75% (21/28 patients) in patients with suspected CAD and 87% (39/44 patients) in patients with previous MI. Only the patients with a previous MI and a negative exercise ECG showed 100% accuracy (n = 14). We conclude that reinjection of 201Tl might be withheld in patients with a previous MI and a negative exercise ECG. For patients with previous MI and a positive exercise ECG, and for patients with suspected coronary artery disease regardless of the result of their exercise ECG, reinjection of 201Tl should be strongly considered if the redistribution images are abnormal, because of the suboptimal diagnostic accuracy of the exercise ECG in these patients.

One-year prognosis of patients with normal planar or single-photon emission computed tomographic technetium 99m-labeled sestamibi exercise imaging.

The favorable prognostic significance of normal 201Tl stress perfusion images, even in the presence of known coronary artery disease, has been well documented. Relatively few data are available with regard to the prognostic significance of normal planar and single-photon emission computed tomographic (SPECT) stress 99mTc-labeled sestamibi (99mTc-sestamibi) images. The prognostic significance of normal exercise 99mTc-sestamibi myocardial perfusion imaging was evaluated in 208 consecutive patients. All patients were referred for evaluation of chest pain syndrome. One hundred eight patients (52%) underwent SPECT imaging, 79 patients (38%) underwent planar imaging, and 21 patients (10%) underwent both planar and SPECT imaging. One hundred seventy-five patients (84%) had a normal or nondiagnostic exercise electrocardiogram, and 33 patients (16%) had a positive exercise electrocardiogram. Follow-up was 13.5 +/- 2 months and was complete in 99.5% of patients. No patient died of cardiac causes during follow-up. One patient (0.5%) had a nonfatal myocardial infarction and four patients (2%) had unstable angina necessitating revascularization. There was no difference in rate of cardiac events between men and women or whether SPECT or planar imaging was used. However, 33 patients with normal 99mTc-sestamibi imaging and a positive exercise electrocardiogram had a significantly higher cardiac event rate than had patients with negative exercise electrocardiograms (9% vs 1%, p < 0.025). Patients with normal 99mTc-sestamibi exercise SPECT or planar imaging results and a normal or nondiagnostic exercise electrocardiogram have a favorable 1-year prognosis. Patients with normal 99mTc-sestamibi images and a positive stress electrocardiogram have a less favorable outcome.

Predictive Value of a Negative Exercise Electrocardiogram

Conventionally, if an exercise electrocardiogram does not show evidence of ischemia, the patient must have achieved at least 85% of the predicted maximum heart rate for that test to be considered negative. However, no documentation of the validity of this practice exists. Thus, we evaluated the exercise electrocardiograms of 164 patients who had also undergone coronary angiography within 6 months of the exercise test. The predictive value of a negative exercise electrocardiogram was determined for each percentage point between 50 and 90% of the age-predicted maximum heart rate achieved or exceeded. The predictive value was found to increase modestly between 65 and 80% of the predicted maximum heart rate with no major changes above or below this range. Thus, it appears reasonable (in the setting of a hospital-based exercise laboratory) to either consider a negative exercise electrocardiogram as a valid finding if at least 80% of the predicted maximum heart rate is achieved, or preferably to simply report the negative finding with the percent maximum heart rate attained and the proviso that the predictive value of the test is progressively improved as higher heart rates are attained.

Usefulness of dipyridamole perfusion scintigraphy in patients with negative exercise electrocardiogram with low-grade exercise

Usefulness of dipyridamole perfusion scintigraphy in patients with negative exercise electrocardiogram with low-grade exercise

Exercise thallium-201 scintigraphy and prognosis in typical angina pectoris and negative exercise electrocardiography

Patients with a history of typical angina but negative exercise electrocardiography represent a subgroup with an intermediate likelihood of having coronary artery disease and future cardiac events. A retrospective study of the prognostic utility of stress-redistribution thallium-201 scintigraphy was performed in 190 such patients. A second group of 203 patients with typical angina and a positive exercise electrocardiogram were analyzed for comparative scintigraphic purposes. The cardiac event rate for the 144 negative exercise electrocardiogram patients with normal thallium results was 5 vs 15% in the 46 patients with abnormal thallium results (p = 0.01). These patients were further stratified into high (14 to 18%), intermediate (9%) and low (<2%) risk groups for future cardiac events based on combining the thallium results with the percentage of maximal predicted heart rate achieved. A multivariate analysis revealed that an abnormal thallium result was the only significant correlate of future cardiac events. Mechanisms responsible for the discordant finding of a negative exercise electrocardiogram in patients with typical angina include (1) false-positive angina symptomatology in low prevalence coronary artery disease groups in whom the thallium test is negative, and (2) “electrocardiographically silent” ischemia in patients in whom the thallium test is positive. These findings reveal that thallium stress-redistribution scintigraphy can be used to stratify 1-year prognosis in this subgroup of patients with typical angina and negative exercise electrocardiograms.

Reciprocal change in ST segment in acute myocardial infarction: correlation with findings on exercise electrocardiography and coronary angiography.

The clinical relevance of reciprocal changes in the ST segment occurring at the time of acute myocardial infarction was studied prospectively in 85 consecutive uncomplicated cases. Reciprocal depression of the ST segment was defined as depression of 1 mm or more in electrocardiogram leads other than those reflecting the infarct. All patients underwent maximal, symptom limited treadmill stress testing two weeks after the infarct and coronary angiography six weeks after infarction. Forty six patients had inferior, 34 anterior, and five true posterior infarction. Of the 51 patients with reciprocal changes, 45 (88%) developed exercise induced ST segment depression in areas remote from the infarction zone. At angiography all 45 patients were shown to have stenoses greater than 70% in at least two major vessels. Four patients had negative exercise electrocardiograms and were sequently shown to have single vessel disease subtending their infarct, and the remaining two patients had a false negative treadmill test result. Of the 27 patients without reciprocal changes, 21 (78%) had negative treadmill stress test results associated with single vessel coronary disease. Five had positive stress test results and multivessel coronary disease, and one had a false negative stress test result. The remaining seven patients had ST segment elevation without Q wave formation in the reciprocal areas and were assessed separately. Of these, six had positive stress test results and multivessel coronary disease and one had a negative stress test result and single vessel coronary disease to the infarct area. Twenty one patients with anterior infarcts (62%) and 27 with inferior infarcts (59%) had reciprocal changes. No differences emerged in the relation between infarct site, reciprocal change, and presence of additional coronary disease. At follow up of the 51 patients with reciprocal changes in the ST segment 36 had become symptomatic, of whom 29 had undergone coronary artery bypass surgery. By contrast, only four of the 27 patients without reciprocal changes in the ST segment had developed symptoms, and two of these had undergone coronary revascularisation. Reciprocal ST segment depression at the time of acute myocardial infarction may identify patients with severe coronary disease who are at risk of subsequent cardiac events and appears to be as reliable as results of early postinfarction treadmill stress testing in predicting the underlying coronary anatomy. When the electrocardiogram does not show reciprocal changes treadmill testing provides valuable additional information.

The value of exercise tests in the follow-up of patients who underwent transluminal coronary angioplasty

We describe the functional and anatomical follow-up of 25 patients who underwent percutaneous transluminal coronary angioplasty in our hospital. In addition, the relative value of different non-invasive methods in predicting a restenosis in the late follow-up period is described. Before angioplasty all patients had subjective and objective signs of coronary artery disease, mainly due to proximal circumscript one-vessel disease. The anatomical evolution was studied by angiographic investigation before, early and late after angioplasty. At the same time intervals we determined the functional level as based on history, exercise electrocardiography, thallium-201 scintigraphy at rest and maximal exercise and technetium ejection fraction determination at rest and maximal exercise. Our data show that angioplasty is a good method of treatment for a selected group of patients with coronary artery disease. The mean stenosis of the dilated vessel decreased significantly from 83% before to 38% late after angioplasty ( P < 0.001). Furthermore the functional status of the patients improved as reflected by the decrease in anginal complaints ( P < 0.001), the increase in negative exercise electrocardiograms (0.01 < P < 0.02), exercise level (0.01 < P < 0.02) and ejection fraction difference between rest and maximal exercise ( P < 0.001) and the decrease in thallium ischemic defects ( P < 0.001). Comparison of the different non-invasive methods shows that the evolution of the ejection fraction difference between rest and exercise is the most reliable way to discover a possible restenosis in the late follow-up period.