Table 1.

Physiological analogs of PDF parameters and parameter-derived indexes

PDF Parameter or IndexPhysiological AnalogSignificant Findings
k, N/mChamber stiffness (dP/dV)k is linearly related to chamber stiffness, dP/dV (21)
c, N·s−1·m−1Viscoelastic loss indexIn normal LVEF diabetic rats and humans (6, 35), c, but not k, is significantly higher, compared with nondiabetic controls
xo, mEffective volumetric loadxo is linearly related to the velocity-time integral of the E-wave (20)
kxo, NPeak AV pressure gradientkxo model-derived peak driving force, correlates with peak AV gradient better (2) than 4v2
cEpeak, NMaximum resistive force opposing fillingCurrent study shows cEpeak and kxo (peak AV gradient) are linearly related independent of load
1/2kxo2 JStored elastic strain energyInitial (maximum) potential energy available to power filling (20)
  • PDF, parameterized diastolic filling; k, spring constant; c, damping constant; xo, initial spring displacement; kxo, maximum driving force, cEpeak, peak resistive force; AV, atrioventricular; LVEF, left ventricular ejection fraction; v2, velocity squared.