Avtor/Urednik		Lumens, Joost; Delhaas, Tammo; Kirn, Borut; Arts, Theo
Naslov		Modeling ventricular interaction: a multiscale approach from sarcomere mechanics to cardiovascular system hemodynamics
Tip		članek
Vir		In: Altman R, Dunker KA, Hunter L, et al, editors. Biocomputing 2008: proceedings. World scientific publishing,
Leto izdaje		2008
Obseg		str. 378-89
Jezik		eng
Abstrakt		Direct ventricular interaction via the interventricular septum plays an important role in ventricular hemodynamics and mechanics. A large amount of experimental data demonstrates that left and right ventricular pump mechanics influence each other and that septal geometry and motion depend on transmural pressure. We present a lumped model of ventricular mechanics consisting of three wall segments that are coupled on the basis of balance laws stating mechanical equilibrium at the intersection of the three walls. The input consists of left and right ventricular volumes and an estimate of septal wall geometry. Wall segment geometry is expressed as area and curvature and is related to sarcomere extension. With constitutive equations of the sarcomere, myofiber stress is calculated. The force exerted by each wall segment on the intersection, as a result of wall tension, is derived from myofiber stress. Finally, septal geometry and ventricular pressures are solved by achieving balance of forces. We implemented this ventricular module in a lumped model ofthe closed-loop cardiovascular system (CircAdapt model) The resulting multiscale model enables dynamic simulation of myofiber mechanics, ventricularcavity mechanics, and cardiovascular system hemodynamics. The modelwas tested by performing simulations with synchronous and asynchronous mechanical activation of the wall segments. The simulated results of ventricular mechanics and hemodynamics were compared with experimental data obtained before and after acute induction of left bundle branch block (LBBB) in dogs. The changes in simulated ventricular mechanics and septal motion as aresult of the introduction of mechanical asynchrony were very similar to those measured in the animal experiments. In conclusion, the module presented describes ventricular mechanics including direct ventricular interaction realistically and thereby extends the physiological application range of the CircAdapt model.