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A cylindrical model of contraction of left ventricle of the heartSyomin F.A., Tsaturyan A.K.

Institute of Mechanics, Lomonosov Moscow State UniversityCardiac tissue as elastic continuum

Assumed deformations of the ventricleHHrInrInDH R/r

Fiber orientation within the ventricle wall(r)

Stress equilibrium equationsp0T33T33

Boundary conditions

Windkessel model for hemodynamic processes

RperLVQinRi, LiPa, CPv

P0Computational modeling P0, mm HgPa, mm HgV, mL

D*z

rIn + 0.5*(rOut - rIn)rOutrIn

L, mL, m

Radial distribution of sarcomere lengths

L, mL, mt, st, sr, cmr, cm

1.7062.39

1.612.51Hypertrophic cardiomyopathy

P0, mm HgPa, mm HgV, mL 2xF2x

D*zDilated cardiomyopathyP0, mm HgPa, mm HgV, mL

vmax2x1.2xV01.5xD*z

SummaryA 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.Syomin Fyodor

Institute of Mechanics, Lomonosov Moscow State University

san@aviel.ru