Turbulent vs. Vortex Ring Energy Losses in the Left Ventricle

Left ventricular flows in the human heart are very complex due to the intricate geometry, the pulsatile character of the flow, the interaction of the jets with the LV flexible walls, and the unsteady motion of the leaflets, which generate intrinsically complicated flow structures. Furthermore, although mechanical heart valves (MHV) have received universal recognition, their performance is still unmatched to that of the natural valves. The flow past MHVs induces a combination of flow characteristics, which are clearly dependent on the specific valve design and valve orientation. Traditionally, valve performance and hemodynamics have been quantified using effective orifice size and pressure gradients. However, quality and direction of flow, often overlooked, are also important aspects of valvular function and relate to valve design and orientation. One of the key characteristics in LV flows is the shear layers shedding past heart valves which generate vortex ring formation resulting into energy entrapment, thus reducing the efficiency of the heart.