MOMENTUM AND ENERGY TRANSFER IN CARDIAC PUMPING

Kinematic and dynamic characteristics of systolic flow in a left ventricle are studied by using a computational analysis with magnetic resonance imaging (MRI) data of normal ventricular motion. The three-dimensional flow is well analyzed on several longitudinal sections, revealing the generation of a pair of vortex rings at the end diastole. The momentum generated by the ventricular contraction is in concert with the vortices for systolic flow to the aorta. The work-energy equation is useful for quantifying cardiac pumping characteristics from computational fluid dynamic (CFD) solutions of the Navier–Stokes equations. Energy dissipation and work done by viscous stresses are small for normal cardiac pumping, and they almost balance with each other. The work done by pressure and kinetic energy delivered to blood flow by ventricular contraction is practically equal to the energy flux at the aortic root and the rate change of kinetic energy in the ventricle.