Evolution of systolic function and myocardial perfusion, evaluated by gated-SPECT, in the first year after acute myocardial infarction

Introduction and objectives. Systolic function and myocardial perfusion are evaluated before hospital discharge and can change during follow-up. The purpose of this study was to evaluate these parameters by gated-SPECT in the first year after acute myocardial infarction. Patients and method. We studied 74 consecutive patients with a first uncomplicated acute myocardial infarction (49 infero-lateral and 25 anterior) by stress-rest Tc-99m-tetrofosmin and rest-gated-SPECT before hospital discharge (6-8 days after admission) and one year after myocardial infarction. Results. The ejection fraction (EF) increased > 5% in 51% of infero-lateral infarcts and 28% of non-revascularized anterior infarcts. EF increased significantly (48.4 +/- 8% to 54.6 +/- 8.7%; p < 0.0001, mean difference: 6.2; 95% IC, 2.8-9.5) and systolic volume decreased (51.3 +/- 19.2 ml to 44.3 +/- 19.4 ml; p = 0.001; mean diff.: 7.67; 95% IC, 1.5-13.8) in infero-lateral infarctions. The rest perfusion index in the necrotic region improved (2.3 +/- 0.57 to 2.17 +/- 0.58; p = 0.004; mean diff.: 0.18; 95% IC, 0.003-0.36) in inferolateral infarcts and the ischemia index remained unchanged between the first and second studies. Conclusions. Left ventricular systolic function can change during the first year of evolution, a significant improvement being seen in infero-lateral infarctions. The ejection fraction increased > 5% in half of these patients, as opposed to only a quarter of anterior infarctions. This improvement was associated to increased myocardial perfusion at rest.