We investigated the criteria for the coupling of the left ventricle (LV) and the arterial system to maximize @entity64 work (SW) and the transformation of LV pressure-volume area ( @entity939 ) to SW. We studied eight conscious @entity235 that were instrumented to measure LV pressure and determine LV volume from three ultrasonically determined dimensions. The LV end-systolic pressure (PES)-volume (VES) relation was determined by caval occlusion. Its slope (EES) was compared with the arterial elastance (EA) and determined as PES per @entity64 volume. At rest, with intact reflexes, EES/EA was 0.96 +/- 0.20 EES/EA was varied over a wide range (0.18-2.59) by the infusion of graded doses of @entity2647 and @entity1854 before and during administration of @entity452 . Maximum LV SW, at constant inotropic state and end-diastolic volume ( @entity34882 ), occurred when EES/EA equaled 0.99 +/- 0.15. At constant @entity34882 and contractile state, SW was within 20% of its maximum value when EES/EA was between 0.56 and 2.29. The conversion of LV @entity939 to SW increased as EES/EA increased. The shape of the observed relations of the SW to EES/EA and SW/ @entity939 to EES/EA was similar to that predicted by the theoretical consideration of LV PES-VES and arterial PES- @entity64 volume relations. We conclude that the LV and arterial system produce maximum SW at constant @entity34882 when EES and EA are equal; however, the relation of SW to EES/EA has a broad plateau. Only when EA greatly exceeds EES does the SW fall substantially. However, the conversion of @entity939 to SW increases as EES/EA increases. These observations support the utility of analyzing LV-arterial coupling in the pressure-volume plane.

Left ventricular-arterial coupling in conscious XXXX .

@entity64 :: ('MESH:D020521', 'Disease') :: ['stroke', 'LV stroke'] @entity939 :: ('CHEBI:17246', 'Chemical') :: ['PVA'] @entity452 :: ('MESH:D004280', 'Chemical') :: ['dobutamine'] @entity235 :: ('9615', 'Species') :: ['dogs'] @entity1854 :: ('MESH:D009599', 'Chemical') :: ['nitroprusside'] @entity34882 :: ('MESH:C535393', 'Disease') :: ['VED'] @entity2647 :: ('MESH:D010656', 'Chemical') :: ['phenylephrine']
@entity235 :: (9615,Species) :: ['dogs']
