Effect of @entity10129 on coronary resistance, contractility and XXXX consumption of the isolated blood-perfused @entity235 left ventricle.

@entity308 @entity235 @entity26 @entity10129 @entity2142 @entity453
@entity10129 reportedly has little direct myocardial effect. However, because of interactions between the heart and vascular load, the effects on myocardial contractility and left ventricular @entity26 consumption (LVO2) have not been established. The authors performed experiments on six isolated, blood-perfused @entity235 left ventricles that were isovolumically contracting and paced at constant rate. @entity453 ( @entity453 ) and coronary blood flow were measured for evaluation of coronary vascular resistance, and coronary arteriovenous @entity26 difference was measured for determination of LVO2. Intracoronary injection of 1 and 10 micrograms of @entity10129 decreased coronary vascular resistance by 16.9 and 36.8% ( @entity453 approximately 40 mm Hg), respectively, and by 21.5 and 47.7% ( @entity453 approximately 80 mm Hg). At both doses, @entity10129 caused no decrease in peak systolic pressure as long as @entity453 was kept constant at 80 mm Hg. However, when @entity453 was decreased to 40 mm Hg, peak systolic pressure was significantly decreased even without @entity10129 . This impaired contractile state was associated with a decreased coronary blood flow and a slight decrease in LVO2, whereas 10 micrograms of @entity10129 at @entity453 approximately 80 mm Hg increased LVO2 significantly. Using the end-systolic pressure-volume relationship as an index of contractility, the authors found @entity10129 not to change the contractile state at @entity453 approximately 80 mm Hg. They conclude that @entity10129 decreases coronary vascular resistance over a wide range of @entity453 . It neither depresses the contractile state nor decreases LVO2 in the @entity235 left ventricle. @entity10129 might effectively counteract @entity2142 by dilating the coronary vessels without @entity308 myocardial contractility as found in this study on normal ventricle.
