Independent prognostic risk factors for patients referred because of suspected acute myocardial infarction without confirmed diagnosis. Prognosis after discharge in relation to medical history and non-invasive investigations.

Variables associated with risk of cardiac events, i.e. acute myocardial infarction (AMI) or cardiac death after discharge, were studied in patients who had been referred to coronary care units because of suspected AMI due to chest pain, but in whom this was not confirmed. The patients were all under 76 years of age, and were followed from 12 to 24 months, median 14 months. The estimated percentage without a cardiac event in 257 patients after one year was 91.3. On the basis of prognostic and clinical importance the analyzed variables included selected aspects of the medical history, electrocardiogram on admission in all 257 patients, subsequent electrocardiogram at rest, exercise test, thallium scintigraphy, chest X-ray, echocardiography, systolic time intervals and Holter monitoring when possible in 217 patients. Multivariate analysis identified combined electrocardiogram at rest and during exercise as the only variable with independent prognostic information. The presence of ST segment deviation, Q-wave, negative T-wave or intraventricular block in the electrocardiogram at rest or an abnormal ST segment response during exercise, increased the hazard of a cardiac event by a factor of 11.8. It is concluded that patients without confirmed AMI are at risk following discharge. These patients should undergo an exercise test and those with an abnormal electrocardiogram at rest and/or during exercise should be followed closely after discharge.