A STRUCTURAL MODEL OF THE LEFT-VENTRICLE INCLUDING MUSCLE-FIBERS AND CORONARY VESSELS - MECHANICAL-BEHAVIOR IN NORMAL CONDITIONS

A structural model of the left ventricle is presented. It is a cylindr ical thick-walled model composed of muscle fibre models and coronary v essel models. The ventricular wall is divided in ten layers to account for the transmural variation of myofibre and coronary vessel orientat ion. These structures give the global performance of the ventricular m odel depending on their own behaviour and on the way they are interfac ed. The results refer both to the global ventricular performance and t he behaviour of the different components. In particular they suggest a n appreciable contribute of the coronary capillary during the early fi lling phase in enlarging the ventricle; during this phase the capillar y vessels exert an extensive force in the radial direction, due to inn er coronary pressure, equal to 20-30 percent - depending on the layer - of the force exerted by the fibres. This occurrence explains, in our opinion, the observed cardiac function improvement when the arterial coronary pressure is increased, known as 'gardenhose' effect.