Lee Waite

A Computer Model of Early Diastolic Filling through the Mitral Valve

The current paper presents a computer model of early diastolic (E-wave) left ventricular filling through the mitral valve. It is believed that this lumped-parameter model will be clinically useful, for example in the diagnosis of diastolic dysfunction. The model is based on the solution of the ordinary differential equations describing flow through the mitral valve, as well as equations that model the intrinsic and extrinsic behaviour of a mitral valve with variable orifice area (mimicking the opening and closing of the valve leaflets). The model was developed and calibrated using porcine data. The model has now been further validated in 12 canine trials. Values are reported of canine atrial and ventricular stiffness, active relaxation characteristics, valve natural frequency, damping coefficient, and effective orifice area measured by solving the inverse problem to obtain a best-fit match between canine empirical and simulated waveforms. The best fit was determined by minimizing the error between the simulated and empirical pressure and velocity waveforms using a minimized sum-of-squares figure of merit. The paper also presents human data addressing the feasibility of using the model in man, with Doppler velocity waveforms as the primary input to the model. The paper reports parameters measured in human patients by solving the inverse problem.

A Lumped-Parameter Model of Mitral Valve Blood Flow for Assessment of Diastolic Left Ventricular Filling

Congestive heart failure (CHF) is a condition in which the heart cannot pump sufficient blood to the body. Approximately 23 million people are diagnosed worldwide with CHF, with about 2 million new cases each year. While mild to moderate CHF can be treated in most people, the majority of patients with advanced CHF die within one year. Consequently, one of the major goals in the fight against life threatening heart disease is early causal diagnosis of CHF.