Equilibrium Volume and Passive Pressure-Volume Relationship in the Intact Canine Left Ventricle
In this chapter we have described a unique method of left ventricular volume clamping designed to quantify the passive properties of the intact ventricle. We prevented complete (end-systolic clamping) or partial filling at different times in diastole. The ventricle thus relaxed completely at different volumes, and we generated pressure-volume coordinates for the passive ventricle that included negative, as welll as positive, values of pressure. We then determined the equilibrium volume, that is, volume at zero transmural pressure, in the working ventricle. We characterized the passive pressure-volume relation with a logarithmic approach that is physically more realistic than the traditional exponential. Finally, we discussed the importance of the concepts of equilibrium volume an restoring forces for diastolic mechanics.
KeywordsLeft Ventricular Volume Transmural Pressure Equilibrium Volume Mitral Flow Inotropic State
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- 6.Nikolic S, Yellin EL, Tamura K, Vetter H, Tamura T, Meisner, JS, Frater RWM (1988) Passive properties of canine left ventricle: diastolic stiffness and restoring forces. Cric Res 62: 1210–1222Google Scholar
- 12.Robinson TF, Cohen-Gould L, Remily RM, Capasso JM, Factor SM (1985) Extracellular structures in heart muscle. In: Harris P, Poole-Wilson PA (eds) Advances in myocardiology, vol 5 Plenum, New YorkGoogle Scholar