Cardiac rotation and relaxation after anterolateral myocardial infarction

Background Both systolic and diastolic dysfunction have been observed in pa tients with anterolateral myocardial infarction, Diastolic dysfunction is r elated to disturbances in relaxation and diastolic filling. Objective To analyse cardiac rotation, regional shortening and diastolic re laxation in patients with anterolateral infarction. Methods Cardiac rotation and relaxation in controls and patients with chron ic anterolateral infarction were assessed by myocardial tagging. Myocardial tagging is based on magnetic resonance imaging and allows us to label spec ific myocardial regions for imaging cardiac motion (rotation, translation a nd radial displacement). A rectangular grid was placed on the myocardium (b asal, equatorial and apical short-axis plane) of each of 18 patients with c hronic anterolateral infarction and 13 controls. Cardiac rotation, change i n area and shortening of circumference were determined in each case. Results The left ventricle in controls performs a systolic wringing motion with a clockwise rotation at the base and a counterclockwise rotation at th e apex when viewed from the apex. During relaxation a rotational motion in the opposite direction (namely untwisting) can be observed. In patients wit h anterolateral infarction, there is less systolic rotation at the apex and diastolic untwisting is delayed and prolonged in comparison with controls. In the presence of a left ventricular aneurysm (n = 4) apical rotation is completely lost. There is less shortening of circumference in infarcted and remote regions. Conclusions The wringing motion of the myocardium might be an important mec hanism involved in maintaining normal cardiac function with minimal expendi ture of energy. This mechanism no longer operates in patients with left ven tricular aneurysms and operates significantly less than normal in those wit h anterolateral hypokinaesia. Diastolic untwisting is significantly delayed and prolonged in patients with anterolateral infarction, which could expla in the occurrence of diastolic dysfunction in these patients. Coron Artery Dis 11:261-267 (C) 2000 Lippincott Williams & Wilkins.