T-Y TUBE MODEL OF HUMAN ASCENDING AORTIC INPUT IMPEDANCE

This paper proposed a T-Y tube model to simulate the input impedance o f arterial system. It improves and extends the asymmetric T-tube model which was first proposed by O'Rourke([1]) and developed later by Liu et al. ([2]). Based on the asymmetric T-tube model, a T-Y tube model w as proposed by adding branching tubes which represent the iliac arteri es. All the tubes are considered to be uniform, viscoelastic, longitud inally tethered cylindrical tubes. The upper tube terminates with a wi ndkessel model, while the terminal arterioles of the lower tube are ex pressed as a resistance. After proper evaluation of the parameters, th e impedance of the arterial system is calculated under normal physiolo gical and hypertensive condition. The model can predict impedance in g ood agreement with the experimentally obtained data no matter in norma l physiological condition or in pathological condition. In comparison with the asymmetric T-tube model, T-Y tube model is closer to anatomy structure of the human arterial system and at the same time much simpl er than the extremely complex multiple-branching tube model. Therefore it will be a valuable model in studying the influences of various par ameters on aorta impedance and ventricular-vascular coupling.