The pressure recovery ratio: The invasive index of LV relaxation during filling. Model-based prediction with in-vivo validation.
Using a simple harmonic oscillator model (PDF formalism), every early filling E-wave can be uniquely described by a set of parameters, (x(0), c, and k). Parameter c in the PDF formalism is a damping or relaxation parameter that measures the energy loss during the filling process. Based on Bernoulli's equation and kinematic modeling, we derived a causal correlation between the relaxation parameter c in the PDF formalism and a feature of the pressure contour during filling - the pressure recovery ratio defined by the left ventricular pressure difference between diastasis and minimum pressure, normalized to the pressure difference between a fiducial pressure and minimum pressure [PRR = (P(Diastasis)-P(Min))/(P(Fiducial)-P(Min))]. We analyzed multiple heart beats from one human subject to validate the correlation. Further validation among more patients is warranted. PRR is the invasive causal analogue of the noninvasive E-wave relaxation parameter c. PRR has the potential to be calculated using automated methodology in the catheterization lab in real time.
Zhang
Wei
W
Department of Physics, Washington University, USA. weizhang@hbar.wustl.edu
Shmuylovich
Leonid
L
Kovacs
Sandor J
SJ
D000465:Algorithms; D001696:Biomechanical Phenomena; D001703:Biophysics / Q000379:methods; D003198:Computer Simulation; D006339:Heart Rate; D006352:Heart Ventricles / Q000473:pathology*; D006439:Hemodynamics; D006801:Humans; D008955:Models, Cardiovascular; D015233:Models, Statistical; D009200:Myocardial Contraction / Q000502:physiology*; D009991:Oscillometry; D011312:Pressure; D013997:Time Factors; D018608:Ultrasonography, Doppler / Q000379:methods