Characterization of Diastolic Vortex Dynamics in Left Ventricular Heart Failure Using Lagrangian Particle Tracking Velocimetry

Heart failure (HF) is a leading cause of cardiovascular mortality, but diagnosis and management are hindered by limited understanding of fluid dynamics during HF progression. While evidence suggests altered vortex formation correlates with clinical outcomes, systematic characterization across HF severities remains limited. This study utilizes Lagrangian particle tracking to investigate 3D vortical flows in an index-matched compliant left ventricle phantom with bioprosthetic valves across ejection fractions of 0.5 (normal), 0.4 (mild HF), and 0.3 (severe HF). Four key characteristics are evaluated: vortex formation time (VFT), turbulent kinetic energy (TKE), normalized penetration depth (VDi), and normalized vortex length (VLi). Results reveal systematic vortex deterioration with increasing HF severity. Normal conditions exhibit strong, coherent vortices with VDi = 0.800 and VLi = 0.351, showing a deep and elongated vortex structure. Progressive HF severity shows dramatic reductions, with VFT declining by 40% in mild HF and 65% in severe HF, and TKE dropping by 62% and 93% respectively. Vortex penetration depth and length decrease similarly. These results reflect weakened inflow momentum failing to sustain coherent vortex formation, causing premature breakdown and altered energy cascade from organized motion to dissipative structures. These new insights into the fluid mechanical basis of cardiac dysfunction could potentially inform improved diagnostic and therapeutic strategies.