Changes in absolute and relative importance in the prognostic value of ventricular systolic function and congestive heart failure after acute myocardial infarction

Changes in the importance of left ventricular (LV) systolic dysfunction and congestive heart failure (CHF) with time after an acute myocardial infarction (AMI) after the introduction of thrombolytic therapy have not been studied. LV systolic function, measured as wall motion index (WMI) by echocardiography, was assessed in 6,676 consecutive patients with an enzyme-confirmed AMI. So that changes in the prognostic value of WMI or CHF could be studied, separate analyses were performed at selected time periods. Average monthly mortality (deaths per 100 patients per month) was determined from life-table analyses, with groups divided by WMI above and below 1.2 (a WMI >1.2 corresponds to an ejection fraction >0.35) or by presence and/or absence of CHF. Relative risk (95% confidence intervals [CI]) was determined by proportional hazard models, including baseline characteristics. In patients with LV dysfunction or CHF, monthly mortality was high during the first month (18.3 +/- 1.6% and 20.2 +/- 1.6%, respectively), decreased during the first year, and was stable thereafter (0.8 +/- 0.1% and 1.0 +/- 0.1%, respectively, average monthly mortality after year 3). The relative risk of LV dysfunction decreased from 2.4 (CI 2.0 to 2.9) to 1.3 (CI 1.0 to 1.6) in the same period. The relative risk of CHF decreased from 2.9 (CI 2.3 to 3.8) to 1.6 (CI 1.3 to 2.0). In patients without LV dysfunction or CHF, monthly mortality was relatively high during the first month (5.2% +/- 0.7% and 3.4% +/- 0.6%, respectively) but decreased within the first year to low, stable values (0.6% +/- 0.1% and 0.4% +/- 0.1%, respectively, average monthly mortality after year 3]. In patients who received thrombolytic therapy, the relative risk associated with a WMI less than or equal to 1.2 decreased from 3.0 (CI 2.0 to 4.4) to 1.3 (CI 0.9 to 1.6) and from 3.2 (CI 2.0 to 5.1) to 1.7 (CI 1.2 to 2.4) in patients with CHF. The risk of dying decreases steeply with rime after an AMI with or without LV dysfunction or CHF and stabilizes at low values after 1 year. This is in contrast to the relative importance of these risk factors, which is maintained for greater than or equal to 5 years but decreases with time. (C) 1998 by Excerpta Medico, Inc.