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SUMMARY:Re-entry and fibrillation in an electro-mechanical model of the hu
 man ventricles - Nash\, M (Auckland)
DTSTART:20090721T133000Z
DTEND:20090721T134500Z
UID:TALK19174@talks.cam.ac.uk
CONTACT:Mustapha Amrani
DESCRIPTION:We present an integrative 3D electro-mechanical model of the h
 uman heart ventricles (RVLV)\, constructed from diffusion tensor magnetic 
 resonance imaging data provided by Drs Helm\, Winslow and McVeigh (Johns H
 opkins University and NIH). Mathematical models of electrical activity (TN
 NP) and contractile tension (NHS) of cardiac myocytes are coupled within a
  transversely isotropic passive mechanical (Guccione) constitutive framewo
 rk embedded within the RVLV model. Excitation-contraction coupling is achi
 eved via the intracellular calcium concentration of the biophysical myocyt
 e models. Mechano-electrical feedback is represented by stretch-activated 
 channels\, which carry currents that are modulated by local deformation. N
 umerical model integration combines an explicit finite differences scheme 
 for the electrophysiology with a non-linear finite element method for the 
 mechanics. The model was tuned and verified by simulating a normal ventric
 ular cycle and comparing the resulting myocardial strain distributions wit
 h experimental recordings. This human RVLV model was used to investigate t
 he effects of mechano-electrical feedback on re-entrant wave dynamics. We 
 examine factors that cause wavebreak and the degeneration of stable re-ent
 ry into fibrillatory activity. We identify the mechanisms of this transiti
 on to VF\, and study the 3D organisation of mechanically induced VF in the
  human heart.
LOCATION:Seminar Room 1\, Newton Institute
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