Are routine non-invasive tests useful in prediction of outcome after myocardial infarction in elderly people?

Abstract

Many patients with acute myocardial infarction undergo tests to identify ischaemia, left-ventricular dysfunction, and arrhythmias. We examined the usefulness of these tests in clinical practice by comparing the ability of a cardiologist to predict outcome at 1 year after infarction with and without knowledge of the results of an exercise test, radionuclide angiogram, and 24 h Holter electrocardiographic (ECG) recording. The study was limited to patients older than 65 years, who have a greater risk of cardiovascular sequelae and undergo fewer interventional procedures. The patient's own cardiologist predicted outcome on a standard rating scale, based on clinical findings and routine hospital tests. He then made a second prediction after seeing the non-invasive test results. Two other cardiologists not involved in the care of the patient independently made similar predictions. Success in predicting outcome was assessed by comparison of differences between the first and second predictions in the area under receiver operating characteristic curves. During 1 year's follow-up there were 24 cardiovascular deaths and 3 recurrent myocardial infarctions among the 147 patients. There were no significant differences in mean curve areas between the first and second predictions for the patients' own cardiologist (0.62 [SE 0.06] vs 0.60 [0.06]) or the other cardiologists (0.63 [0.06] vs 0.64 [0.06] and 0.61 [0.06] vs 0.65 [0.06]). All predictions were significantly (p < 0.05) better than chance. Prediction of outcome in older patients after myocardial infarction is not improved by knowledge of the results of an exercise test, radionuclide angiogram, or 24 h Holter ECG recording.