title: Modeling the instantaneous pressure-volume relation of the left ventricle: a comparison of six models.
abstract: Simulations are useful to study the heart's ability to generate flow and the interaction between contractility and loading conditions. The left ventricular pressure-volume (PV) relation has been shown to be nonlinear, but it is unknown whether a linear model is accurate enough for simulations. Six models were fitted to the PV-data measured in five sheep and the estimated parameters were used to simulate PV-loops. Simulated and measured PV-loops were compared with the Akaike information criterion (AIC) and the Hamming distance, a measure for geometric shape similarity. The compared models were: a time-varying elastance model with fixed volume intercept (LinFix); a time-varying elastance model with varying volume intercept (LinFree); a Langewouter's pressure-dependent elasticity model (Langew); a sigmoidal model (Sigm); a time-varying elastance model with a systolic flow-dependent resistance (Shroff) and a model with a linear systolic and an exponential diastolic relation (Burkh). Overall, the best model is LinFree (lowest AIC), closely followed by Langew. The remaining models rank: Sigm, Shroff, LinFix and Burkh. If only the shape of the PV-loops is important, all models perform nearly identically (Hamming distance between 20 and 23%). For realistic simulation of the instantaneous PV-relation a linear model suffices.
authors: Department of Pulmonary Diseases, Institute for Cardiovascular Research, VU University Medical Center, De Boelelaan 1117, 1081 HV, Amsterdam, The Netherlands. jw.lankhaar@vumc.nl
authors: Jan-Willem
authors: JW
authors: Lankhaar
authors: Fleur A
authors: FA
authors: Rövekamp
authors: Paul
authors: P
authors: Steendijk
authors: Theo J C
authors: TJ
authors: Faes
authors: Berend E
authors: BE
authors: Westerhof
authors: Taco
authors: T
authors: Kind
authors: Anton
authors: A
authors: Vonk-Noordegraaf
authors: Nico
authors: N
authors: Westerhof
mesh_terms: D000818:Animals; D001794:Blood Pressure / Q000502:physiology*; D006352:Heart Ventricles; D006801:Humans; D008955:Models, Cardiovascular; D016276:Ventricular Function / Q000502:physiology*