Modified asymmetric T-tube model to infer arterial wave reflection at the aortic root

A modified version of the T-tube model was constructed to represent the systemic arterial loading system as seen by the left ventricle. This model consisted of two uniform tubes connected in parallel. It differed from the original T-tube model in that the transmission paths had no frictional losses and were terminated with complex impedances, rather than simple resistors. To estimate model parameters, the authors measured ascending aortic pressure and flow in a group of five open-chest, anesthetized dogs. Parameter estimates were obtained by fitting experimental pressure to the pressure predicted by the model from experimental flow. To check the reliability of the model, an additional experiment was performed where flow in the upper descending thoracic aorta was measured in addition to ascending aorta pressure and flow. The fit between the experiment and model-predicted ascending aortic pressure was satisfactory.