Risk factors and prognosis after discharge for patients admitted because of suspected acute myocardial infarction with and without confirmed diagnosis.

The prognosis regarding cardiac events--acute myocardial infarction (AMI) or cardiac death after discharge--was evaluated in 257 patients admitted because of suspected AMI due to chest pain, but in whom AMI was not confirmed (non-AMI patients). The findings and patient prognoses were compared with those of 275 patients with confirmed AMI. All patients were younger than 76 years and free of severe chronic diseases, and no cause of chest pain other than possible ischemic heart disease was found. The patients were followed for cardiac events for 11 to 24 months (median 14). The prognoses for the non-AMI patients were significantly better than those for the AMI patients (p = 0.05). The proportion without a cardiac event after 1 year was estimated at 91% and 86%, respectively. In the non-AMI patients, angina pectoris, previous AMI and electrocardiographic changes on admission (intraventricular block and permanent or transient ST-T changes) were significant predictors of cardiac events by univariate and multivariate analysis. In the AMI patients, female gender, heart failure, previous AMI and angina pectoris were significant predictors of cardiac events by univariate analysis. With use of multivariate analysis, female gender, heart failure and angina pectoris were independent predictors of cardiac events. Thus, non-AMI patients admitted with chest pain have a high risk of cardiac events after discharge. The risk is highest when there is evidence of coronary artery disease (electrocardiographic changes on admission and angina pectoris or previous AMI.