Progressive changes in ventricular structure and function during the year after acute myocardial infarction

Abstract

To investigate the long-term changes in left ventricular structure and function after myocardial infarction, 51 patients with a first myocardial infarction (17 anterior, 23 inferior, and 11 non-Q wave) were studied by two-dimensional echocardiography at the time of entry into the hospital, at 3 months, and 1 year after infarction. The left ventricular endocardial surface was reconstructed from these echocardiograms, and the endocardial surface area (ESA) index (in cm 2/m 2) and area of abnormal wall motion (AWM in cm 2) were quantitated. Despite different trends in the ESA index between entry and 3-month values in those with and without early infarct expansion, a decrease in the ESA index from 3 months to 1 year was noted in anterior and non-Q wave infarctions (anterior with early expansion: 96.3 ± 8.6 to 81.5 ± 4.2 cm 2/m 2, p < 0.05; anterior without early expansion: 59.7 ± 2.0 to 54.7 ± 2.0 cm 2/m 2, p < 0.01; non-Q wave: 64.1 ± 3.5 to 57.9 ± 4.4 cm 2/m 2, p < 0.01). The mean decline in ESA from 3 months to 1 year of 8.9 ± 2.5 cm 2 was independent of initial infarct size. Regional function, as represented by the area of AWM, was also improved but the timing of the improvement was related to the location and size of the infarction. Although decreases in AWM were noted in both the inferior and non-Q wave groups from entry to 3 months (inferior: 27.1 ± 3.3 to 21.8 ± 3.4 cm 2, p < 0.5; non-Q wave: 18.9 ± 4.5 to 12.1 ± 5.5 cm 2, p < 0.05), decreases in AWM in anterior infarctions were not present until the 3-month to 1-year time period (anterior with expansion: 79.1 ± 18.6 to 59.8 ± 14.9 cm 2, p < 0.05; anterior without expansion: 27.7 ± 6.2 to 16.5 ± 4.9 cm 2, p < 0.05). Even in the absence of intervention, global left ventricular size decreases and regional wall motion improves in both Q wave and non-Q wave infarctions when quantitated 1 year after i infarction.