Estimation of elastic and viscous properties of the left ventricle based on annulus plane harmonic behavior.
Assessment of left ventricular (LV) function with an emphasis on contractility has been a challenge in cardiac mechanics during the recent decades. The LV function is usually described by the LV pressure-volume (P-V) diagram. The standard P-V diagrams are easy to interpret but difficult to obtain and require invasive instrumentation for measuring the corresponding volume and pressure data. In the present study, we introduce a technique that can estimate the viscoelastic properties of the LV based on harmonic behavior of the ventricular chamber and it can be applied non-invasively as well. The estimation technique is based on modeling the actual long axis displacement of the mitral annulus plane toward the cardiac base as a linear damped oscillator with time-varying coefficients. The time-varying parameters of the model were estimated by a standard recursive linear least squares (RLLS) technique. LV stiffness at end-systole and end diastole was in the range of 61.86-136.00 dyne/g.cm and 1.25-21.02 dyne/g.cm, respectively. The only input used in this model was the long axis displacement of the annulus plane, which can also be obtained non-invasively using tissue Doppler or MR imaging.
Kheradvar
Arash
A
California Institute of Technology, Pasadena, CA 91125, USA. arashkh@caltech.edu
Milano
Michele
M
Gorman
Robert C
RC
Gorman
Joseph H
JH
Gharib
Morteza
M
D000818:Animals; D001683:Biological Clocks / Q000502:physiology*; D003198:Computer Simulation; D004548:Elasticity; D006801:Humans; D008955:Models, Cardiovascular; D009068:Movement / Q000502:physiology*; D009200:Myocardial Contraction / Q000502:physiology*; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D013314:Stress, Mechanical; D016277:Ventricular Function, Left / Q000502:physiology*; D014783:Viscosity