Survivorship patterns in the posthospital phase of myocardial infarction

Abstract

A prospective postinfarction follow-up study was used to identify subsets of patients with different survival patterns. Nine hundred forty patients who survived the hospital phase of an acute myocardial infarction were followed for 12-60 months. During the 5-year follow-up, 115 patients died of cardiac causes. Univariate analysis showed that prior myocardial infarction (PMI), left ventricular dysfunction (LVD) in the CCU, one or more ventricular premature depolarizations (VPDs) on a 6-hour Holter recording, and anterior myocardial infarction were significantly (p<0.01) more frequent in patients who died of cardiac causes than in survivors. Survivorship analyses revealed a variety of survival patterns, depending on the presence or absence of the risk factors PMI, LVD, VPD and anterior infarction, as well as their interactive combinations. A combinatin of anterior infarction with LVD and VPDs identified a high-risk subset that made up 15% of the myocardial infarction population, and this group had 6-month and 3-year survival rates of 85% and 70%, respectively. After we excluded the high-risk subset, PMI, LVD and VPD each had significant yet independent influence on survival, with PMI having a greater effect on mortality than either LVD or VPDs. A low-risk subset that made up 24% of the population was identified by the absence of PMI, LVD and VPDs, and this group had a 3-year survival of 94%.