Capabilities of supine exercise electrocardiography versus exercise radionuclide angiography in predicting coronary events

The ability of supine exercise electrocardiography and exercise radionuclide angiography to predict time to subsequent cardiac events (cardiac death, nonfatal myocardial infarction or late coronary bypass grafting or angioplasty) were compared in 265 patients with normal resting electrocardiograms who were not taking digoxin. All patients had undergone coronary catheterization and were initially treated medically. Follow-up study was performed at a median of 51 months. Separate logistic regression models, which had been previously developed to predict 3-vessd or left main coronary artery disease (CAD), were compared using a Cox regression analysis to predict time to a subsequent cardiac event. The exercise electrocardiography model, consisting of the magnitude of ST depression, exercise heart rate and patient gender, was a powerful predictor (chi-square = 30.8, p < 0.0001) of subsequent events. The exercise radionuclide angiography model, which included the exercise response of the pressure-volume ratio in addition to the exercise electrocardiography variables, had similar prognostic power (chi-square = 31.8, p < 0.0001). In a separate analysis considering only cardiac death and nonfatal myocardial infarction, the exercise electrocardiography model remained a significant predictor of events (chi-square = 12.2, p < 0.001). None of the radionuclide angiography variables added significantly to the prognostic power of the exercise electrocardiography model. Thus, in patients with a normal resting electrocardiogram who are not taking digoxin, the supine exercise electrocardiography model that predicts 3-vessel or left main CAD also predicts future cardiac events. Exercise radionuclide angiography does not provide any additional prognostic information in such patients.