Introduction: Acute myocardial infarction causes left ventricular (LV) remodelling, which forms the substrate for its early and late complications. The aim of this experimental study was to evaluate the acute changes in LV functional geometry after acute myocardial infarction using echocardiography and to investigate the effect of continuous intravenous dobutamine administration on those changes.
Methods: In 22 pigs acute myocardial infarction was induced by ligation of the anterior descending branch of the left coronary artery. In 11 animals dobutamine was administered at a rate of 5 microg/kg/min (Group B), while the remainder (Group A) served as controls. Before infarction and 5, 15, 45 and 75 minutes after, the fractional shortening of the long (FSL) and short (FSS) axes of the LV were measured echocardiographically and the ejection fraction (EF) was calculated.
Results: In Group A FSL and EF reduced significantly after infarction (p < 0.0001), while FSS increased significantly (p < 0.05). In Group B FSL and EF reduced significantly 5 minutes after infarction and then returned progressively to normal values after 15 min (EF) and 45 min (FSL). FSS did not change significantly during 75 minutes after infarction.
Conclusions: Dobutamine, administered at a rate of 5 microg/kg/min during acute experimental anterior myocardial infarction, before the appearance of early complications, may prevent the acute, unfavourable remodelling of the LV, as manifested by a decrease in FSL and EF and a compensatory increase in FSS.