To determine the essential mechanism of increased systolic wall motion, i.e., hyperkinesis, in a nonischemic region (NIR) during acute ischemia, we simultaneously evaluated global and regional function of the excised, cross-circulated canine left ventricle connected to a volume servo pump before and after coronary occlusion. Regional areas were determined with pairs of orthogonal subendocardial sonomicrometers in the ischemic region (IR) and NIR. After coronary occlusion with left ventricular end-diastolic and stroke volumes kept constant, the amount of systolic area shrinkage (delta A) in NIR increased by 33 +/- 41% (p less than .05), despite a decrease in end-diastolic regional area by 3 +/- 4% (p less than .05). Regional work obtained from the wall tension-regional area (T-A) loop in NIR decreased by 50 +/- 24% due to a similar decrease in afterload despite the presence of hyperkinesis, indicating regional systolic unloading. When left ventricular end-diastolic volume was subsequently increased with a constant stroke volume, delta A in NIR increased at the expense of a further decrease in delta A in IR. The end-systolic T-A relationship in NIR remained unchanged, whereas that in IR markedly shifted rightward, suggesting that...Continue Reading
Early changes in contractility and coronary blood flow in the normal areas of the ischemic porcine heart
Quantitative evaluation of left ventricular regional work from wall tension-regional area loop in canine heart
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Augmentation of regional function in nonischemic myocardium during coronary occlusion measured with two-dimensional echocardiography
Coupling between regional myocardial oxygen consumption and contraction under altered preload and afterload
Remote myocardial dysfunction after acute anterior myocardial infarction: impact of left ventricular shape on regional function: a magnetic resonance myocardial tagging study
Effects of intravenous metoprolol on global and regional left ventricular function after coronary arterial reperfusion in acute myocardial infarction
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The effects of angiotensin II signaling pathway in the systolic response to acute stretch in the normal and ischemic myocardium
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Application of three-dimensional speckle tracking echocardiography to assess left ventricular regional work using wall tension-regional area loop
Dynamic left ventricular outflow tract obstruction in a patient with acute coronary syndrome and without the apical akinesia: Potential alternative mechanisms causing a dynamic left ventricular outflow tract obstruction other than a compensatory basal hyperkinesis.
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