Mitral Valve Regurgitation Murmurs – Insights from Hemoacoustic Computational Modeling

Mitral regurgitation (MR) is the backflow of the blood through the mitral valve from the left ventricle into the left atrium during systole and the incidence of MR is 2% worldwide (Theal et al., Can J Cardiol., 20, 5, 2004). MR results in decreased ejection fraction and may progress to heart failure (Carabello, Mod Concepts Cardiovasc Dis., 57, 10, 1988). Thus, methods that can enable, cheap, non-invasive and accurate diagnosis detection and classification) of MR could have a significant impact on the management of this condition. MR results in a systolic murmur which can serve as an indicator of this condition. In the current study, we employ hemoacoustic simulations to quantify the characteristics of these murmurs for various MR severities and regurgitant jet directions. Blood flow is simulated by solving the incompressible Navier Stokes equations using the immersed-boundary code ViCar3D. The resultant pressure fluctuations on the wall surface serve as the source of the murmur and the propagation of the murmur through the thorax is modeled as a 3D elastic wave in a linear viscoelastic material. The murmur intensity and frequency characteristics are correlated with the degree of MR as well as the direction of the MR jet, and implications for automated auscultation-based diagnosis of MR are discussed.