Kinematic modeling using the parametrized diastolic filling formalism reveals that chamber relaxation and viscoelasticity, rather than chamber stiffness, most often differentiate diastolic dysfunction.
Because 50% of heart failure hospital admissions have diastolic heart failure (DHF) quantifying diastolic function (DF) has reached new prominence. Conventionally DF indices have been computed from shape-based features (height, duration, area) of Doppler waveforms such as the E-wave, (transmitral flow velocity), or E'-wave (mitral annular velocity) without regard to causal mechanisms. Solution of the 'inverse problem' has been achieved via the parametrized diastolic filling (PDF) formalism, a linear, kinematic model which treats the elastic, recoil-driven suction-pump attribute of the left ventricle as a damped simple harmonic oscillator (SHO). PDF uses the E-wave as input and generates stiffness (k), relaxation/ damping (c) and load (x(o)) as output. Scientific successes include the prediction that filling must be driven by a linear, bi-directional spring, later validated as a property of the giant cardiac protein titin, which generates a recoiling force at the cellular level in early diastole. Selected recent kinematic modeling achievements include: explanation why E-wave deceleration time must be determined jointly by stiffness (k) and relaxation (c), rather than by stiffness alone; LV equilibrium volume is the volume at diastasis; solution of the load-independent index of diastolic function (LIIDF) problem; solution of the isovolumic pressure decay (IVPD) problem. Clinical application reveals that contrary to dogma, chamber relaxation/viscoelasticity (PDF parameter c) rather than chamber stiffness (PDF parameter k) most often differentiates between controls vs. diastolic dysfunction subjects, thereby providing mechanistic insights into DHF.
Sándor J. Kovács (Tue,) conducted a review in Diastolic heart failure. Parametrized diastolic filling (PDF) kinematic modeling vs. Conventional shape-based Doppler waveform indices was evaluated. Kinematic modeling using the parametrized diastolic filling formalism reveals that chamber relaxation and viscoelasticity, rather than chamber stiffness, most often differentiate diastolic dysfunction.