Syomin F.A., Tsaturyan A.K. Institute of Mechanics, Lomonosov Moscow State University

H λHλH r In ρ r In Dλ H ⋅ R/r

α(r)α(r)

p0p0 T 33

R per LV Q in R i, L i P a, C PvPv P0P0

P 0, mm Hg P a, mm Hg V, mL

λ D*z ρ

r In + 0.5*(r Out - r In ) r Out r In L, μm

t, s r, cm

P 0, mm Hg P a, mm Hg V, mL 2x F

λ D*z ρ

P 0, mm Hg P a, mm Hg V, mL v max 2x 1.2x V0V0 1.5x

λ D*z ρ

A kinetic model of cardiac muscle was used to simulate contraction of the left ventricle using a cylindrical approximation of its shape. Computational results are in good agreement with the time course of hemodynamic and geometrical parameters during a heart beat. The model shows the importance of the change in fiber orientation within the ventricle wall. The ventricle twist leads to more uniform distribution of sarcomere length. The model confirms that the changes in ventricle geometry found in hearts with hypertrophic and dilated cardiomyopathies result in the maintenance of the stroke volume in spite of decreased contractile force or shortening velocity, respectively.