Using a mathematical model for diastolic filling through the mitral valve to determine cardiac properties

The current paper uses a computer model of early diastolic filling through the mitral valve, implemented in MATLAB, to find representative values for specific parameters used to define the model. The model is a lumped parameter model configured such that a velocity waveform, obtained from a patient’s echocardiogram, serves as its primary input and the correspondingly predicted left atrial and left ventricular pressure waveforms are the primary outputs. Values were found for the following parameters: atrial and ventricular stiffness (a and v); active-relaxation characteristics, including time constant for isovolumetric pressure decay (Td0) and pressure decay constant (Pd0); valve natural frequency (), and damping coefficient (D). Pre-operative (pre-op) and post-operative (post-op) data were used to find corresponding pre-op and post-op values for each of the parameters. A sequential Bonferroni correction technique applied after an unpaired two-sample t-test yielded no statistical difference between pre-op and post-op values for any of the parameters; however, the results are limited by small sample size.