Pressure reservoir-wave separation applied to the coronary arterial data

Pressure waveforms measured at different locations in the coronary arteries are similar. Previous work has shown the cardiovascular system can be modelled as a Windkessel and wave system. We now suggest that simultaneously measured coronary pressure, P, and velocity, U, can be used to calculate the separated reservoir, P, and wave, p, pressure such that P = P + p. This separation enables us to deduce the resistance of the coronary microcirculation as it varies with time; resistance during systole being almost double the resistance during diastole. Wave intensity analysis is used to separate forward and backward waves. This requires knowledge of the local wave speed, c, which is determined from the data using the sum of squares technique. Wave timings differ at different sites in the coronary tree, revealing the complexity of wave propagation. Their mapping give a fairly complete picture of wave travel in the coronary network and insight into the physiology of coronary artery flow in health and disease.