Regression Analysis of the Left–ventricular Isochoric Pressure Decay of the Heart: Four or Five Model Parameters?

Biophysical models predicting the relaxation of cardiomyocytes1 take into account a lot more variables than regression models analysing the left ventricular relaxation in human and animal hearts. These isochoric (isovolumic) pressure decay curves are often described by an exponential2 or logistic3 time constant. Both these three–parametric regression models are regarded unsatisfactory4, 5. Consequently, a four–parametric extension of the logistic (or: hyperbolic tangent) model was introduced4,