The interaction between left ventricular wall motion and intraventricular flow propagation in acute and chronic ischemia

Myocardial ischemia has been associated with left ventricular (LV) post-systolic shortening. The combination of Tissue Doppler imaging (TDI) and high frame rate acquisition of 2-D color flow makes it possible to study the interaction between LV wall motion and intraventricular flow propagation. The aim of this study was in a clinical model to study the impact of acute myocardial ischemia and prior myocardial infarct might have on LV flow patterns, and to explain the underlying mechanisms from the tissue Doppler data. LV flow propagation and tissue velocities during early diastole were studied in 18 healthy individuals, 17 patients with prior anterior myocardial infarct and 16 patients before and during percutaneous coronary intervention (PCI) of the left anterior descending artery. Normal individuals had intraventricular flow propagation towards apex during isovolumic relaxation. During this early diastolic time phase, myocardial velocities measured at mid and apical septal segment were directed away from apex. Prior to PCI, patients without myocardial infarction had similar findings as in normals. In contrast, each patient with either prior myocardial infarction or PCI induced acute ischemia had flow propagation opposite to normals and tissue velocities reversed towards apex during early diastole. Reversal of early diastolic LV flow propagation in acute and chronic anterior myocardial ischemia reflects post-systolic shortening in the dyskinetic apical and septal myocardial segments.