The relationship heart rate(HR)-end diastolic volume(EDV) is represented by linear function -0.00247654 HR + 1.18574.
The coeficients was choosen to solve normal state and critical zero state: (Solve[{a*75 + b == 1, a*HR + b == 0, diastoleTime[HR] == 0}, {a, b}]).
It means the next ventricle filling model:
cardiac cycle time (T) = (60/HR) [s]
systolic contraction time (Ts) = (0.3*T^0.5) [s]
diastolic filling time (Tdf) = T - Ts - 0.18*Ts [s]
steady-state filling curve:
axes x .. filling time = Tdf [s]
axes y .. entered volume part = stroke volume (SV)/normal_SV [x 100 %]
EDV = SV + pre(ESV) = effect(HR) * ((EDV_without_HR_effect - pre(ESV)) + pre(ESV)