How does transient myocardial ischemia affect echocardiographic systolic and diastolic left ventricular wall motion in an open-chest dog model?
Transient myocardial ischemia in a canine model produces characteristic echocardiographic changes, including early relaxation followed by diastolic inward motion, which may translate to human ischemic responses.
Left ventricular (LV) wall motion (anterior and posterior) and simultaneous LV pressure were recorded during 30-second left anterior descending (LAD) or circumflex (CX) coronary artery occlusions in open-chest dogs to provide an echocardiographic model of the evolution of wall motion changes during myocardial ischemia. Prominent diastolic echocardiographic motion changes of progressive decrease in LV wall rapid-filling velocities (RFS), slow-filling velocities (SFS), and increased end-diastolic diameter were accompanied by a marked increase in initial and end-diastolic pressures (150% and 70%, respectively; all p less than 0.05). Early (within ten seconds) and progressive decrease in rat (SES), amplitude (E), and duration (TTR) of systolic motion were noted with an increased systolic diameter (p less than 0.05). Ischemic regions developed a characteristic pattern with early relaxation followed by a diastolic inward motion (DIM). These observations confirm and extend other investigators' findings on the motion of the ischemic myocardium and may be applicable to responses to transient myocardial ischemia noted in humans.
Conetta et al. (Sun,) studied this question.
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