Results Of Exercise Electrocardiography Research Articles

Short- and long-term prognostic performance of exercise ECG and myocardial perfusion SPECT.

Myocardial perfusion SPECT(MPS) and exercise electrocardiography(Ex-ECG) results are of prognostic importance for short-term follow up duration. However, the value of MPS or Ex-ECG findings for long-term risk assessment is less evident as underlying risk factors for ischemic heart disease (IHD) gain in importance. To assess the short- and long-term prognostic value of MPS and Ex-ECG in relation to known risk factors. An observational study of 908 patients (age 63 years, 49% male, 45% prior IHD) referred for MPS and Ex-ECG. Follow-up was divided into two periods (short-term: <5 years and long-term: >5 years). Cardiac events were defined as a composite of acute myocardial infarction, unstable angina, unplanned revascularization and cardiovascular death. The composite endpoint occurred in 95 patients (short-term follow up) and in 94 patients (long-term follow up). In multivariable models stress testing had a strong predictive value for short-term follow up (HR for MPS = 2.9, CI = 1.9-4.5, p < 0.001 and HR for Ex-ECG = 2.1, CI 1.3-3.3, p = 0.002), but no predictive value for long-term follow up (HR for MPS = 0.9, CI = 0.5-1.5, p = 0.70 and HR for Ex-ECG = 1.0, CI = 0.6-1.6, p = 0.92). Male sex and prior IHD were significant predictors regardless of follow up duration. Age, diabetes and decreased exercise capacity were risk factors for long-term follow up. The prognostic value of MPS and Ex-ECG results are strong for short-term follow up but diminish over time and do not contribute significantly in multivariable models after 5 years. Long-term prognosis is primarily governed by underlying risk factors and exercise capacity.

Using Coronary Artery Calcium Score as Diagnostic Tool in Symptomatic Chronic Coronary Syndrome Patients in a Real-Life Setting.

The coronary artery calcium (CAC) score can be used to increase (CAC score > 0) or decrease (CAC score = 0) the likelihood of coronary artery disease (CAD). We compared the CAC score with the pre-test probability (PTP) for CAD (low, intermediate, and high). Furthermore, we compared the CAC score with exercise electrocardiography (ECG) and compared both tests with coronary angiography. We retrospectively identified patients with angina and/or dyspnea for whom CAC score was used to increase or decrease the likelihood of CAD. Of 882 patients, majority had low (45%) or intermediate (44%) PTP. Patients with higher PTP had significantly higher CAC scores (Cramer's V = 0.29, p < 0.0001). Most patients (57%) had a CAC score of zero, especially those with low (73%) and intermediate (49%) PTP. However, 20% of patients with high PTP had CAC score of zero. Higher CAC scores were observed in patients with abnormal exercise ECG, but association was weak and not significant (Cramer's V = 0.13, p = 0.08). Moreover, more than 40% of patients with an abnormal exercise ECG had CAC score of zero. Higher CAC scores were associated with more severe abnormalities on coronary angiography (Cramer's V = 0.43, p < 0.0001), whereas there was no association between results of exercise ECG and coronary angiography (Cramer's V = 0.11, p = 0.91). CAC score can be used in addition to PTP to increase or decrease the likelihood of CAD, and it might be more useful than exercise ECG in the diagnostic work-up of chest pain.

Exercise Electrocardiography and Computed Tomography Coronary Angiography for Patients With Suspected Stable Angina Pectoris

Recent European guidance supports a diminished role for exercise electrocardiography (ECG) in the assessment of suspected stable angina. To evaluate the utility of exercise ECG in contemporary practice and assess the value of combined functional and anatomical testing. This is a post hoc analysis of the Scottish Computed Tomography of the Heart (SCOT-HEART) open-label randomized clinical trial, conducted in 12 cardiology chest pain clinics across Scotland for patients with suspected angina secondary to coronary heart disease. Between November 18, 2010, and September 24, 2014, 4146 patients aged 18 to 75 years with stable angina underwent clinical evaluation and 1417 of 1651 (86%) underwent exercise ECG prior to randomization. Statistical analysis was conducted from October 10 to November 5, 2019. Patients were randomized in a 1:1 ratio to receive standard care plus coronary computed tomography (CT) angiography or to receive standard care alone. The present analysis was limited to the 3283 patients who underwent exercise ECG alone or in combination with coronary CT angiography. The primary clinical end point was death from coronary heart disease or nonfatal myocardial infarction at 5 years. Among the 3283 patients (1889 men; median age, 57.0 years [interquartile range, 50.0-64.0 years]), exercise ECG had a sensitivity of 39% and a specificity of 91% for detecting any obstructive coronary artery disease in those who underwent subsequent invasive angiography. Abnormal results of exercise ECG were associated with a 14.47-fold (95% CI, 10.00-20.41; P < .001) increase in coronary revascularization at 1 year and a 2.57-fold (95% CI, 1.38-4.63; P < .001) increase in mortality from coronary heart disease death at 5 years or in cases of nonfatal myocardial infarction at 5 years. Compared with exercise ECG alone, results of coronary CT angiography had a stronger association with 5-year coronary heart disease death or nonfatal myocardial infarction (hazard ratio, 10.63; 95% CI, 2.32-48.70; P = .002). The greatest numerical difference in outcome with CT angiography compared with exercise ECG alone was observed for those with inconclusive results of exercise ECG (5 of 285 [2%] vs 13 of 283 [5%]), although this was not statistically significant (log-rank P = .05). This study suggests that abnormal results of exercise ECG are associated with coronary revascularization and the future risk of adverse coronary events. However, coronary CT angiography more accurately detects coronary artery disease and is more strongly associated with future risk compared with exercise ECG. ClinicalTrials.gov Identifier: NCT01149590.

The Role of Aortic Stiffness Parameters in Evaluating Myocardial Ischemia.

BackgroundArterial stiffness is a process resulting in deterioration of hemodynamic function of the aorta, a decrease in its compliance and elasticity, caused by the proportional change of components of the extracellular matrix. Although many researches have been done to determine the etiologies of myocardial ischemia in the absence of obstructive coronary artery disease, none of them has investigated the relation between the parameters of aortic stiffness and the myocardial ischemia documented by the exercise stress test. The present cross-sectional study aimed to investigate the difference of aortic stiffness parameters between the groups separated by exercise stress test result as positive and negative ischemic findings in the absence of obstructive coronary artery disease.MethodsThe present study included 79 patients who were admitted to Istanbul Faculty of Medicine, Department of Cardiology with complaint of chest pain. Forty patients (21 women and 19 men) have ischemic findings on the exercise electrocardiography (ECG) test and 39 patients (20 women and 19 men) have normal exercise ECG results. The patients who have positive exercise ECG findings underwent coronary angiography and all the patients had non-obstructive coronary artery disease. Demographic features (age, sex and comorbidities) were statistically similar between the groups. Aortic stiffness measurements (pulse wave velocity, pulse pressure, aortic augmented pressure, augmentation index, systolic pressure-time index, diastolic pressure-time index and subendocardial viability ratio) were done with tonometric methods.ResultsThere was no significant difference between the two groups in terms of the aortic stiffness parameters. Systolic blood pressure (P = 0.33), diastolic blood pressure (P = 0.24), pulse pressure (P = 0.60), systolic pressure-time index (P = 0.10), diastolic pressure-time index (P = 0.91), subendocardial viability ratio (P = 0.19), aortic augmented pressure (P = 0.87), augmentation index (P = 0.58) and pulse wave velocity (P = 0.56) were detected between the two groups. Biochemical parameters were found similar between the two groups. Only low-density lipoprotein levels were slightly higher in patients with negative exercise stress test result (139 vs. 123 mg/dL, P = 0.02).ConclusionThere is no finding supporting that the aortic stiffness identifies the patients with non-obstructive coronary artery disease but with signs of myocardial ischemia and further investigation of other causes of myocardial ischemia is required.

Discrepancy between stress electrocardiographic changes and nuclear myocardial perfusion defects in the prognostic assessment of patients with chest pain

ObjectivesThe aim of the present study was to determine the long-term prognostic value provided by the exercise electrocardiographic (ECG) response to nuclear myocardial perfusion imaging (MPI) in the evaluation of patients with chest pain, focusing on patients with a discrepancy between the two tests. MethodsA total of 1460 consecutive patients (777 female; 62.6±11.4 years) undergoing exercise myocardial single-photon emission computed tomography (SPECT) were included. The endpoint was the occurrence of acute coronary syndrome, heart failure or cardiac death during follow-up. ResultsIschemic ECG changes were observed during stress testing in 271 patients (18.5%) and 362 patients (24.7%) had positive (abnormal) exercise MPI results. There was a discrepancy between ECG and SPECT findings in 471 patients (32.2%). During the follow-up period (14.0-39.6 months), 224 patients (15.3%) presented cardiac events. The hazard ratios (HR) of ECG and MPI results to predict events were 1.506 (95% CI: 1.113-2.039) and 10.481 (95% CI: 7.799-14.080), respectively. In patients with negative MPI, the ECG response did not predict events (HR 1.214 [95% CI: 0.646-2.282]), the same as in patients with positive MPI (HR 1.203 [95% CI: 0.848-1.705]). Only in hypertensive patients with positive SPECT did the ECG show significant prognostic value (HR 1.937 [95% CI: 1.030-3.642]). In multivariate analysis, positive MPI proved an independent long-term prognostic factor (HR 10.536 [95% CI: 7.759-14.308]), but not ECG (HR 1.356 [95% CI: 0.994-1.850]). ConclusionMPI results (normal vs. abnormal) had strong predictive value and discrepant ECG results had no significant additive prognostic value.

Discrepancy between stress electrocardiographic changes and nuclear myocardial perfusion defects in the prognostic assessment of patients with chest pain

ObjectivesThe aim of the present study was to determine the long-term prognostic value provided by the exercise electrocardiographic (ECG) response to nuclear myocardial perfusion imaging (MPI) in the evaluation of patients with chest pain, focusing on patients with a discrepancy between the two tests. MethodsA total of 1460 consecutive patients (777 female; 62.6±11.4 years) undergoing exercise myocardial single-photon emission computed tomography (SPECT) were included. The endpoint was the occurrence of acute coronary syndrome, heart failure or cardiac death during follow-up. ResultsIschemic ECG changes were observed during stress testing in 271 patients (18.5%) and 362 patients (24.7%) had positive (abnormal) exercise MPI results. There was a discrepancy between ECG and SPECT findings in 471 patients (32.2%). During the follow-up period (14.0-39.6 months), 224 patients (15.3%) presented cardiac events. The hazard ratios (HR) of ECG and MPI results to predict events were 1.506 (95% CI: 1.113-2.039) and 10.481 (95% CI: 7.799-14.080), respectively. In patients with negative MPI, the ECG response did not predict events (HR 1.214 [95% CI: 0.646-2.282]), the same as in patients with positive MPI (HR 1.203 [95% CI: 0.848-1.705]). Only in hypertensive patients with positive SPECT did the ECG show significant prognostic value (HR 1.937 [95% CI: 1.030-3.642]). In multivariate analysis, positive MPI proved an independent long-term prognostic factor (HR 10.536 [95% CI: 7.759-14.308]), but not ECG (HR 1.356 [95% CI: 0.994-1.850]). ConclusionMPI results (normal vs. abnormal) had strong predictive value and discrepant ECG results had no significant additive prognostic value.

Stable Angina Pectoris: Head-to-Head Comparison of Prognostic Value of Cardiac CT and Exercise Testing

To determine and compare the prognostic value of cardiac computed tomographic (CT) angiography, coronary calcium scoring, and exercise electrocardiography (ECG) in patients with chest pain who are suspected of having coronary artery disease (CAD). This study complied with the Declaration of Helsinki, and the local ethics committee approved the study. Patients (n = 471) without known CAD underwent exercise ECG and dual-source CT at a rapid assessment outpatient chest pain clinic. Coronary calcification and the presence of 50% or greater coronary stenosis (in one or more vessels) were assessed with CT. Exercise ECG results were classified as normal, ischemic, or nondiagnostic. The primary outcome was a major adverse cardiac event (MACE), defined as cardiac death, nonfatal myocardial infarction, or unstable angina requiring hospitalization and revascularization beyond 6 months. Univariable and multivariable Cox regression analysis was used to determine the prognostic values, while clinical impact was assessed with the net reclassification improvement metric. Follow-up was completed for 424 (90%) patients; the mean duration of follow-up was 2.6 years. A total of 44 MACEs occurred in 30 patients. Four of the MACEs were cardiac deaths and six were nonfatal myocardial infarctions. The presence of coronary calcification (hazard ratio [HR], 8.22 [95% confidence interval {CI}: 1.96, 34.51]), obstructive CAD (HR, 6.22 [95% CI: 2.77, 13.99]), and nondiagnostic stress test results (HR, 3.00 [95% CI: 1.26, 7.14]) were univariable predictors of MACEs. In the multivariable model, CT angiography findings (HR, 5.0 [95% CI: 1.7, 14.5]) and nondiagnostic exercise ECG results (HR, 2.9 [95% CI: 1.2, 7.0]) remained independent predictors of MACEs. CT angiography findings showed incremental value beyond clinical predictors and stress testing (global χ(2), 37.7 vs 13.7; P < .001), whereas coronary calcium scores did not have further incremental value (global χ(2), 38.2 vs 37.7; P = .40). CT angiography findings are a strong predictor of future adverse events, showing incremental value over clinical predictors, stress testing, and coronary calcium scores. http://radiology.rsna.org/lookup/suppl/doi:10.1148/radiol.11110744/-/DC1.

Disappearance of Angina Pectoris by Lipid-Lowering in Type III Hyperlipoproteinemia

Type III hyperlipoproteinemia is a rare familial disease characterized by marked elevations of serum cholesterol and triglyceride levels caused by an accumulation of remnant lipoproteins in apolipoprotein E2/E2 homozygotes. It is associated with an increased risk for premature atherosclerotic vascular disease. A 55-year-old woman was diagnosed as having type III hyperlipoproteinemia on the basis of skin lesions, serum lipid levels, lipid electrophoresis, and apolipoprotein E genotyping and stable angina pectoris on the basis of typical symptoms and treadmill exercise electrocardiographic results. After 1 year of combination therapy with atorvastatin and fenofibrate, skin xanthomata disappeared, leaving minimal remnants. In addition, there was no exertional chest pain, and treadmill exercise electrocardiographic results were negative. This finding was confirmed by coronary computed tomographic angiography. This case suggests that proper medical therapy can induce the regression of uncomplicated coronary lesions in type III hyperlipoproteinemia.

Comparison of the Value of Coronary Calcium Detection to Computed Tomographic Angiography and Exercise Testing in Patients With Chest Pain

The aim of this study was to investigate the value of coronary calcium detection by computed tomography compared to computed tomographic angiography (CTA) and exercise testing to detect obstructive coronary artery disease (CAD) in patients with stable chest pain. A total of 471 consecutive patients with new stable chest complaints were scheduled to undergo dual-source multislice computed tomography (Siemens, Germany; coronary calcium score [CCS] and coronary CTA) and exercise electrocardiography (XECG). Clinically driven invasive quantitative angiography was performed in 98 patients. Only 3 of 175 patients (2%) with a negative CCS had significant CAD on CT angiogram, with only 1 confirmed by quantitative angiography. In patients with a high calcium score (Agatston score >400), CTA could exclude significant CAD in no more than 4 of 65 patients (6%). In patients with a low-intermediate CCS, CTA more often yielded diagnostic results compared to XECG and could rule out obstructive CAD in 56% of patients. For patients with CAD on CT angiogram, those with abnormal exercise electrocardiographic results more often showed severe CAD (p <0.034). In patients with diagnostic results for all tests, the sensitivity and specificity to detect >50% quantitative angiographic diameter stenosis were 100% and 15% for CCS >0, 82% and 64% for CCS >100, 97% and 36% for CTA, and 70% and 76% for XECG, respectively. In conclusion, nonenhanced computed tomography for calcium detection is a reliable means to exclude obstructive CAD in stable, symptomatic patients. Contrast-enhanced CTA can exclude significant CAD in patients with a low-intermediate CCS but is of limited value in patients with a high CCS.

Usefulness of High Functional Capacity in Patients With Exercise-Induced ST-Depression to Predict a Negative Result on Exercise Echocardiography and Low Prognostic Risk

Although exercise electrocardiography (ExECG) is commonly used to detect coronary artery disease, the diagnostic accuracy and reliability of positive (ischemic) results of ExECG in low- and intermediate-risk populations are limited. Accordingly, many patients with positive results of ExECG undergo secondary evaluation using noninvasive stress imaging such as exercise echocardiography. Functional capacity is a strong predictor of prognosis and, indirectly, of high-risk coronary artery disease. It was hypothesized that high functional capacity in patients with positive results of ExECG would predict (1) negative results on subsequent exercise echocardiography and (2) a low risk for late mortality. Results were analyzed in 104 consecutive patients (79 men, 25 women; mean age 49 years, range 27 to 76) referred for exercise echocardiography after positive results of ExECG with a treadmill workload of > or =10 METs. Late all-cause mortality was also determined in these patients. Exercise echocardiographic results were negative in 93% of patients (97 of 104; 92% of men [73 of 79] and 100% of women [25 of 25]) and positive in 7% (7 of 104). During a mean follow-up period of 7.2 +/- 1.9 years, there was 1 death. In conclusion, high functional capacity in patients with positive results of ExECG is associated with negative exercise echocardiographic results in most patients and very low late mortality. Patients with ischemic ST-segment response on ExECG who achieve workloads of > or =10 METs infrequently require additional noninvasive or invasive evaluation.

Comparison of Prognostic Value of Pharmacologic Stress Echocardiography in Chest Pain Patients With Versus Without Diabetes Mellitus and Positive Exercise Electrocardiography

The aim of this study was to compare the prognostic value of pharmacologic stress echocardiography in diabetic and nondiabetic patients with chest pain and intermediate- to high-threshold positive exercise electrocardiographic results. A total of 935 patients with chest pain (131 diabetic patients) with ST-segment depression > or =1 mm on exercise electrocardiography at > or =75-W workload underwent dipyridamole (n = 786) or dobutamine (n = 149) stress echocardiography and were followed up for the occurence of hard (death and infarction) and major events (death, infarction, and late revascularization). During a median follow-up of 26 months, 158 events (51 deaths, 28 myocardial infarctions, and 79 late revascularizations) occurred: 34 in diabetic and 124 in nondiabetic patients (26% vs 15%, p = 0.003). Independent predictors of hard events were age, diabetes, and ischemia at stress echocardiography. Five-year hard event rates were 24% in patients with and 4% in those without ischemia (p <0.0001). Independent predictors of major events were age, diabetes, hypercholesterolemia, smoking habit, antianginal therapy at the time of testing, and ischemia at stress echocardiography. Five-year major event rates were 46% in patients with and 7% in those without ischemia (p <0.0001). Stress echocardiography results yielded effective prognostic information in diabetic and nondiabetic patients. However, the latter had worse outcomes in both the presence and absence of ischemia. Nevertheless, a nonischemic test result predicted an uneventful 6-month period and 2% major event rate at 1-year follow-up in both populations. In conclusion, stress echocardiography was effective in risk stratifying diabetic and nondiabetic patients with intermediate- to high-threshold ischemic exercise electrocardiographic results. However, major event rates associated with a nonischemic test result were similar in diabetic and nondiabetic patients during the first year of follow-up and markedly increased in the former thereafter.

Assessment of asymptomatic coronary artery disease in apparently uncomplicated type 2 diabetic patients: a role for lipoprotein(a) and apolipoprotein(a) polymorphism.

In patients with uncomplicated diabetes, there is low probability of finding significant coronary artery disease (CAD) by noninvasive tests. Therefore, screening for its presence is not justified, and it is important to find reliable predictors of silent CAD to identify patients with uncomplicated diabetes for further screening. The relationship between lipoprotein(a) [Lp(a)], apolipoprotein(a) [apo(a)] polymorphism, and silent CAD has never been studied. We investigated the association of Lp(a) and apo(a) polymorphism with angiographically documented asymptomatic CAD in type 2 diabetic patients without evident complications. A total of 1,323 diabetic patients without any clinical and electrocardiographic evidence of CAD were evaluated. Of 121 patients with highly positive results of exercise electrocardiography (ECG) (n = 30) or positive results on exercise thallium scintigraphy (n = 91), 103 subjects showed angiographically documented CAD (CAD group). Of 1,106 patients with negative results on exercise ECG, 103 subjects without CAD (NO CAD group) were selected and matched by age, gender, and duration of diabetes to patients in the CAD group. In patients in the NO CAD group, results of exercise ECG, 48-h ambulatory ECG, and stress echocardiography were negative for CAD. The CAD group had higher Lp(a) levels (21.7 +/- 17.7 vs. 15.2 +/- 19.0 mg/dl; P = 0.0093) than the NO CAD group, and a percentage of subjects had at least one small apo(a) isoform (68.9 vs. 29.1%; P = 0.0000) higher than the NO CAD group. Logistic regression analysis showed that apo(a) phenotypes (odds ratio [OR] 8.13, 95% CI 3.65-21.23), microalbuminuria (5.38, 2.44-11.88), smoking (2.72, 1.31-5.64), and Lp(a) levels (2.41, 1.15-5.03) were predictors of asymptomatic CAD. Our investigation reports the first evidence of an independent association of Lp(a) and apo(a) polymorphism with asymptomatic CAD. This suggests that Lp(a) levels and apo(a) phenotypes could be used together with other risk factors as markers of asymptomatic CAD in patients with diabetes.

Prognostic value and quality of life in patients with normal rest thallium-201/stress technetium 99m-tetrofosmin dual-isotope myocardial SPECT

Background. The prognostic value of normal dual-isotope single photon emission computed tomography (SPECT), with technetium 99m-tetrofosmin for the stress images, is not well known. Furthermore, thallium-201 cross talk in the Tc-99m window may reduce the defect severity of the Tc-99m images. Methods and Results. In a consecutive series of 610 patients, 246 patients with normal rest and stress SPECT images by means of visual semiquantitative analysis were included. The patients' pre-test likelihood of coronary artery disease was determined, based on age, sex, symptoms, and the results of stress electrocardiography. Quality of life was assessed by using a mailed self-administered general quality-of-life questionnaire. We compared the mean scores (8 dimensions) of our study population with the scores of 1063 control subjects, sampled randomly out of the inhabitant register of a Dutch city. The mean follow-up period was 25 ± 3 months. Compared with the control group, patients in our study scored lower (less perceived health) for all dimensions of the SF-36 ( P < .05), suggesting a selection of symptomatic or otherwise diseased patients. The primary cardiac event rate was 0.4% per year. The cardiac events occurred in patients with an intermediate-to-high pre-test likelihood of disease and negative or nondiagnostic exercise electrocardiographic results. In a subset of patients with a high pre-test likelihood of coronary artery disease (more than 85%), the primary cardiac event rate was 0.7% per year. Conclusions. Patients with normal results on dual-isotope myocardial perfusion scintigraphy, performed with Tc-99m-tetrofosmin for the stress images, have an excellent prognosis. Furthermore, our results suggest that Tl-201 cross talk in the Tc-99m window may be low and functionally and clinically unimportant. (J Nucl Cardiol 2000;7:333–41.)

Prognostic value of high dose dipyridamole echocardiography in patients with chronic coronary artery disease and preserved left ventricular function

The prognostic value of dipyridamole echocardiography was assessed in patients with chronic coronary artery disease and preserved left ventricular function. Few data are available on the prognostic value of dipyridamole echocardiography in patients with a low risk of cardiac events. Two hundred sixty-eight consecutive patients with stable, proven or suspected coronary artery disease and ejection fraction > or = 0.40 underwent high dose (up to 0.84 mg/kg body weight) dipyridamole echocardiography. In 204 patients definite exercise electrocardiographic (ECG) results were also available. During a mean (+/- SD) follow-up period of 16 +/- 8 months (range 6 to 36), 33 spontaneous events occurred: 15 "hard" events (cardiac death [n = 6], myocardial infarction [n = 9]) and 18 "soft" events (unstable angina). Events occurred more frequently in patients with positive findings on dipyridamole echocardiography (59% vs. 3%, p < 0.001; hard events 24% vs. 2%, p < 0.01). A positive response at the low dose (up to 0.56 mg/kg) identified patients with a high incidence of hard events (7 of 16 patients, sensitivity 50%, specificity 96%). In patients with an exercise ECG, a comparable sensitivity for cardiac events was found (89% vs. 93%, p = NS), but dipyridamole echocardiography was more specific (91% vs. 61%, p < 0.01). A positive response on the low work load exercise ECG (< 8 min) and a positive response to low dose dipyridamole echocardiography had similar accuracy (82% vs. 90%, p = NS). Cox analysis identified dipyridamole echocardiography as the best predictor of cardiac events (odds ratio [OR] 20.9, 95% confidence interval [CI] 10.8 to 37.9); the highest risk of hard events was found in patients with a positive response to low dose dipyridamole echocardiography (OR 25.4, 95% CI 12.2 to 54.1). In patients with chronic coronary artery disease and a low incidence of cardiac events, dipyridamole echocardiography was effective in prognostic stratification, and positive low work load exercise ECG results were a reliable predictor of subsequent events. Consequently, dipyridamole echocardiography should be considered a complementary tool in the presence of high work load positivity or ambiguous exercise ECG results.

Thallium-201 myocardial SPET in strictly defined syndrome X

We reviewed the exercise thallium-201 (201Tl) myocardial single photon emission tomography (SPET) results and clinical data of 28 patients, adhering to a strict definition of syndrome X. All of the patients had a normal resting left ventricular ejection fraction (LVEF) and no cardiac abnormalities. The results of the exercise electrocardiography (ECG) studies were evaluated and compared with the results of 201Tl SPET. Of the 28 patients, only 3 (11%) had a normal 201Tl SPET scan and 25 (89%) had an abnormal 201Tl SPET scan. We found that a normal 201Tl SPET scan was rare when adhering to a strict definition of syndrome X, and the results of exercise ECG did not correlate well with the perfusion defects observed on the 201Tl SPET scan.

Nuclear Cardiology, Current Applications in Clinical Practice

The clinical applications of nuclear cardiology have rapidly expanded since the introduction of suitable imaging cameras and readily applicable isotopes. The currently available methods can provide useful data on estimates of ventricular function and detection of myocardial ischemia for adequate patient management. Two standard procedures are routinely used: (1) myocardial perfusion scintigraphy, eg, with thallium 201; and (2) radionuclide angiocardiography by using technetium 99m-labeled red blood cells. Myocardial perfusion scintigraphy provides information on regional viability and estimates regional myocardial perfusion by measuring regional tracer activity. Thallium 201 is the agent used for noninvasive assessment of myocardial perfusion and for improving the results of exercise electrocardiography. Alternative tests, such as pharmacologic stress testing with dipyridamole, have been proposed as a reliable substitute for exercise testing. Additional quantitative analysis and computed tomography have increased the sensitivity and specificity of thallium scintigraphy. Radionuclide angiography techniques are used for the noninvasive evaluation of cardiac function, right and left ventricular function, and wall motion abnormalities. As in perfusion scintigraphy, radionuclide angiography has proven its value for the detection of coronary artery disease (CAD). Abnormal regional wall motion abnormalities are specific for CAD.

Clinical applications of exercise nuclear cardiology studies in the era of healthcare reform

The challenge for nuclear cardiology is to demonstrate that it can provide more information than competitive modalities at comparable or lower cost. In considering patients for nuclear cardiology procedures, presentations can be divided into 9 subsets: within each subset, nuclear cardiology tests should be employed where incremental information is provided over the information available without performing the test. (1) Patients with no known coronary artery disease (CAD); for <i>diagnosis</i>, nuclear imaging is useful in patients with intermediate probability of CAD. For <i>prognosis</i>, assessment is based on extent of ischemia, where we have shown that nuclear testing provides incremental information, especially in patients with a high likelihood of CAD, such as those with typical angina. In the remaining categories (2–9), nuclear cardiology studies are predominantly used for purposes of risk stratification. Here the greatest value is in patients deemed to be at intermediate risk before nuclear testing. (2) Postmyocardial infarction: stress nuclear imaging provides an alternative to angiography for risk assessment of clinically uncomplicated patients. (3) Poor ventricular function: Nuclear testing is particularly useful for differentiating patients with hibernating myocardium (the defect is reversible), with stunned myocardium (no defect is present), or with myocardial infarction (the defect is persistent). (4) Unstable angina: Following current federal guidelines, nuclear imaging in medically stabilized low-to-intermediate risk patients with unstable angina is likely to increase. (5) Postcatheterization patients: Nuclear imaging is useful when there is uncertainty regarding the choice of medical management or revascularization. (6) Pre-noncardiac surgery patients: Nuclear imaging is clearly helpful in patients with intermediate clinical risk and may provide useful information in clinically high-risk patients. (7) Post-PTCA patients: Due to the intermediate likelihood of restenosis, nuclear scans are frequently employed 2–6 months following intervention. (8) Post-CABG patients: We have demonstrated that exercise scintigraphy (SPECT) provides incremental prognostic information over clinical and exercise electrocardiographic results and is useful when clinical risk of events is considered intermediate. (9) Long-term management: Scintigraphy provides objective information regarding progression or regression of CAD.

Clinical applications of exercise nuclear cardiology studies in the era of healthcare reform

The challenge for nuclear cardiology is to demonstrate that it can provide more information than competitive modalities at comparable or lower cost. In considering patients for nuclear cardiology procedures, presentations can be divided into 9 subsets: within each subset, nuclear cardiology tests should be employed where incremental information is provided over the information available without performing the test. (1) Patients with no known coronary artery disease (CAD); for diagnosis, nuclear imaging is useful in patients with intermediate probability of CAD. For prognosis, assessment is based on extent of ischemia, where we have shown that nuclear testing provides incremental information, especially in patients with a high likelihood of CAD, such as those with typical angina. In the remaining categories (2-9), nuclear cardiology studies are predominantly used for purposes of risk stratification. Here the greatest value is in patients deemed to be at intermediate risk before nuclear testing. (2) Postmyocardial infarction: stress nuclear imaging provides an alternative to angiography for risk assessment of clinically uncomplicated patients. (3) Poor ventricular function: Nuclear testing is particularly useful for differentiating patients with hibernating myocardium (the defect is reversible), with stunned myocardium (no defect is present), or with myocardial infarction (the defect is persistent). (4) Unstable angina: Following current federal guidelines, nuclear imaging in medically stabilized low-to-intermediate risk patients with unstable angina is likely to increase. (5) Postcatheterization patients: Nuclear imaging is useful when there is uncertainty regarding the choice of medical management or revascularization. (6) Pre-noncardiac surgery patients: Nuclear imaging is clearly helpful in patients with intermediate clinical risk and may provide useful information in clinically high-risk patients. (7) Post-PTCA patients: Due to the intermediate likelihood of restenosis, nuclear scans are frequently employed 2-6 months following intervention. (8) Post-CABG patients: We have demonstrated that exercise scintigraphy (SPECT) provides incremental prognostic information over clinical and exercise electrocardiographic results and is useful when clinical risk of events is considered intermediate. (9) Long-term management: Scintigraphy provides objective information regarding progression or regression of CAD.

Comparison of thallium-201 single-photon emission computed tomography and electrocardiographic response during exercise in patients with normal rest electrocardiographic results

This study compared the diagnostic accuracy of exercise thallium-201 single-photon emission computed tomography (SPECT) with the exercise electrocardiographic (ECG) response in patients with normal baseline ECG results. Previous studies comparing exercise thallium imaging with exercise electrocardiography have included patients with abnormal rest ECG results that may have biased the results in favor of thallium imaging. Of 321 patients with a pretest likelihood of coronary artery disease of 70 +/- 29% (mean +/- SD) who underwent exercise stress testing and coronary angiography, 68 had no coronary artery disease; 94 had one-vessel disease; 79 had two-vessel disease; and 80 had three-vessel or left main coronary artery disease. The diagnostic accuracy of SPECT was higher than that of the ECG response (79% vs. 49%, p < 0.0001). Patients with extensive (left main or three-vessel) coronary artery disease were older and had a lower work load, lower heart rate, greater ST segment depression and more extensive perfusion abnormalities than patients with no disease or one- or two-vessel disease. Multivariate discriminant analysis of exercise and thallium variables identified multivessel thallium abnormalities (F = 35), exercise heart rate (F = 18) and extent of ST segment depression (F = 6) as independent predictors of extensive disease. Of the 80 patients with left main or three-vessel disease, 37 (46%) had > or = 2-mm ST segment depression, 44 (55%) had multivessel SPECT abnormalities, and 61 (76%) had either > or = 2-mm ST depression or multivessel SPECT abnormalities (p = 0.0005 vs. the ECG response; p = 0.01 vs. SPECT). In patients with an intermediate to high pretest probability of coronary artery disease and normal baseline ECG results, SPECT is superior to the ECG response in detecting coronary disease. Further, SPECT provides incremental power in identifying patients with extensive (left main or three-vessel) coronary disease.

Diagnostic evaluation of the patient with coronary artery disease.

Evaluation of patients with possible coronary artery disease is a challenge to clinicians who face conflicting pressures in the current practice environment. Sensitivity, accuracy, cost, and access have become considerations in the appropriate selection of diagnostic studies. To review and compare the strengths and shortcomings of commonly employed noninvasive techniques for diagnosing coronary artery disease. The patient's history is still key in establishing a diagnosis. Exercise electrocardiography (ECG) is not as sensitive or specific as exercise echocardiography or radionuclide studies, but it is relatively inexpensive and accessible. Further, new criteria for interpreting the results of exercise ECG may improve its diagnostic accuracy. The predictive value of any test increases in populations where the prevalence of disease is higher, as in patients with known risk factors for coronary artery disease. Patients who cannot exercise or who have concomitant conditions that obscure the results of exercise ECG are candidates for other diagnostic techniques. Rational diagnostic plans for evaluating patients who may have coronary disease can be developed on the basis of existing information and reported experience.