Figure 3.

Examples of four fitted (thick lines) and measured (dots) isochrones of each model. Due to the poor fit of LinFix in diastole, calculation of the filling pressure by evaluating the fitted isochrone for a given end-diastolic volume, would result in nearly the same filling pressure for all loops. Apart from ejection, Shroff and LinFix are identical. Therefore, for Shroff only three fitted isochrones during ejection are shown. (Note the different pressure scale.) In contrast with the other models, during ejection, Shroff does not result in smooth isochrones of a predictable shape due to the dependence on ventricular outflow. Note that the isochrones in isovolumic contraction and relaxation in Burkh partly overlap as a result of an equal α value