Diagnostic value of exercise electrocardiography and thallium myocardial scintigraphy in patients without previous myocardial infarction: a Bayesian approach.

Abstract

SUMMARY The clinical value of combining exertional ECG and postexertional thallium (201T1) scintigraphy was assessed in 160 patients (130 men and 30 women) suspected of having coronary artery disease (CAD) who underwent a coronary arteriography. Based on sex and history, the patients were subdivided in two groups with different prevalences of CAD: Group 1 (high prevalence of CAD = 90%) included 98 men with typical angina pectoris (AP) and group 2 (low prevalence of CAD = 18%) included 32 men and 30 women with atypical AP.Compared with the exertional ECG, myocardial scintigraphy was more sensitive (87% vs 74%) and more specific (89% vs 70%) for the diagnosis of CAD. The combination of the ECG and scintigraphic data was useful if both tests gave concordant results: 100% of true positives (n = 67) and 84% of true negatives (n = 43). In case of discordant results (n = 50), no firm diagnostic conclusion could be made due to the many false-positive (27%) and false-negative (25%) scintigrams.These results are easier to interpret when the prevalence of CAD is taken into account. According to Bayes' theorem, abnormal exercise results confirm CAD when the prevalence is high and normal results rule out CAD when the prevalence is low; also, a normal response to exercise has no predictive value when the prevalence is high. When the prevalence is low, an abnormal ECG or thallium has low predictive value but concordant abnormal responses are highly predictive for CAD (100% of true positives).EXERCISE myocardial perfusion scintigraphy with thallium-201 is useful for detecting myocardial ischemia due to coronary artery disease (CAD) and seems more reliable than the exertional ECG. '-5 In symptomatic patients, the characteristics of the complaints are important and, from a well-taken history, one can evaluate the likelihood of CAD.8 12 Several reports on exertional ECG have indicated that the diagnostic information provided by the test was largely determined by the prevalence of the disease within the population.9" [13][14][15][16][17] This study was undertaken to assess the diagnostic value of exercise thallium scintigraphy and its combination with exertional ECG; in order to analyze the influence of the prevalence of CAD, the patients were subdivided in groups according to the information provided by the history. The prevalence of CAD is almost 100% after an acute myocardial infarction, so patients with a history of infarction were excluded. Material One hundred sixty patients, 130 men and 30 women, suspected of CAD but without evidence of a previous myocardial infarction, were studied. They underwent a multistage maximal exercise test 1 to several days before the arteriographic study. These patients were studied because of the presence of chest pain. Before the exercise test, the patients were carefully questioned by the same physician. From the clinical history, the complaints were subjectively judged to be typical or atypical of angina pectoris (AP). As in a previous study,9 this judgment was based on the location, qualit...

Studies on ergometer exercise testing I. Significance of the type of st‐segment response, sex, and chest pain

“…The specificity and PAN of the absence of typical angina was lower in men. The PAP of typical angina for CAD when associated with positive EECG has been reported to be over 90% in men but 50-75% in women (Detry et al, 1977;Melin et al, 1981). Our results show that the PAP was high for CAD (96% in men and 100% in women) if typical angina, exercise-induced chest pain, and positive EECG response all were present.…”

Contribution of Exercise-Induced Mitral Regurgitation to Exercise Stroke Volume and Exercise Capacity in Patients With Left Ventricular Systolic Dysfunction

“…17 In patients with ischemic heart disease, the presence of inducible myocardial ischemia was excluded by use of thallium imaging as described previously. 18 …”

How can we diagnose coronary heart disease in hypertensive patients?

“…28 ' M Bayes' theorem of conditional probability shows that the positive predictive accuracy of a test (the ratio of true-positive results to both true-positive and false-positive results) is highly dependent on the pretest probability of disease in a given patient population (Table 1). If we assume that the EDITORIAL: CORONARY HEART DISEASE AND HYPERTENSION/Pmanr et al Disease prevalence = 10%; sensitivity = 94%; specificity = 71%; positive predictive accuracy = (94 x 100%)/(94 + 261) = 26%; negative predictive accuracy = (639 x 100%)/(6 + 639) = 99%.…”