Diastolic Abnormalities in Low-Flow and Pacing Tachycardia-Induced Ischemia in Isolated Rat Hearts—Modification by Calcium Antagonists
An increase in left ventricular diastolic pressure relative to volume during spontaneous attacks of angina pectoris  and angina attacks provoked by exercise  or pacing tachycardia [3–5] has been reported by many investigators in patients with coronary artery disease. This decreased left ventricular diastolic distensibility is usually accompanied by a decrease in the rate of left ventricular relaxation. Similar changes in diastolic properties have been observed in open- chest dogs with severe coronary stenoses and super-imposed pacing tachycardia [6,7]. Several possible mechanisms producing such changes have been proposed , and one of the most likely of these is an alteration in intrinsic myocardial properties due to ischemia-induced calcium overload and/or decreased availability of ATP. However, investigations using open-chest dogs could not completely exclude other mechanisms, such as extrinsic diastolic compression by the right ventricle, or dyssynchrony between the ischemic and normal myocardium.
KeywordsIschemia Lactate Agarose Polyethylene Caffeine
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