Neural modulation of ventriculo-aortic coupling index and stroke work based on the alternative Starling curve description

The aim of this study is to analyze the relation between stroke work (SW) and aortoventricular interaction in the normal and the diseased left ventricle. Ventricular end-systolic elastance (Emax) depends on ejection pressure and end-systolic volume, whereas arterial elastance (Ea) refers to the ratio of ejection pressure and stroke volume. Coupling between left ventricle and arterial bed is quantitated by rising Ea/Emax. Reportedly, maximum SW is supposed to reflect conditions of optimal coupling. The authors carried out an analytical analysis, while measurements on humans as reported in the literature are used to document the full range of this relation. The volumetric behavior of the left ventricle can be described on the basis of the Alternative Starling Curve description. This information is then applied to relate Ea/Emax to SW/SWmax. The authors´ results indicate a close resemblance between theoretically predicted data and actual measurements. Also, this study illustrates effects of neural modulation on both the elastance and the SW ratios