A new computer model of mitral valve hemodynamics during ventricular filling.
OBJECTIVE
Quantitative description of left ventricular diastolic filling and mitral valve function remains difficult despite advances in echocardiography. The purpose of the present study was to develop a lumped parameter model of left ventricular filling and validate it in porcine trials under physiological conditions and after valve replacement.


METHODS
Six animals were instrumented with aortic flow meter, left atrial pressure catheter and combined left ventricular pressure-conductance catheter. The model simulates ventricular and arterial pressures and flows during diastolic filling. Input parameters include maximum mitral valve area, blood viscosity and density, atrial compliance, left ventricular active relaxation characteristics and initial pressure and flow values. The outputs of the model are atrial and ventricular pressure as well as transmitral flow as a function of time. The model primarily consists of a system of four first-order, non-linear ordinary differential equations which were solved with MATLAB software.


RESULTS
Left atrial and ventricular pressure data and model flow curves were nearly identical under baseline conditions, during rapid preload reduction by vena caval occlusion and after prosthetic valve replacement. Measured and model based calculation of early diastolic filling volume (E-wave), showed an excellent correlation under all three conditions (r = 0.998, P < 0.0001; r = 0.997, P < 0.0001; r = 0.974, P < 0.0001, respectively) with a mean difference less then two percent.


CONCLUSIONS
The new lumped parameter model of left ventricular filling allows for the first time a detailed simulation of pressure and flow curves in the left heart including transmitral hemodynamics.
Department of Cardiac Surgery, University of Heidelberg, Im Neuenheimer Feld 110, 69120 Heidelberg, Germany. dzsi@hotmail.com
Gábor
G
Szabó
Davis
D
Soans
Andy
A
Graf
Carsten
C
J  Beller
Lee
L
Waite
Siegfried
S
Hagl
D000818:Animals; D001794:Blood Pressure / Q000502:physiology; D002302:Cardiac Output / Q000502:physiology; D003198:Computer Simulation; D006339:Heart Rate / Q000502:physiology; D019918:Heart Valve Prosthesis Implantation / Q000379:methods; D006439:Hemodynamics / Q000502:physiology; D008943:Mitral Valve / Q000502:physiology*; D008955:Models, Cardiovascular; D013552:Swine; D016277:Ventricular Function, Left / Q000502:physiology*