The dynamics of pulsatile flow in the coronary arteries.

The coronary arteries are a system of elastic tubes with one end open to the aorta and with a high resistance at the other end. The basic pattern of coronary input flow is determined 1. by the primary inflow wave due to the aortic pressure pulsation and 2. by a secondary wave which is generated by the periodic obstruction of outflow at the peripheral resistance due to the contraction of the heart. By means of the simplified model of a homogeneous elastic tube, details and oscillations of the coronary flow pattern could be explained as due to reflection and superposition of these primary and secondary waves. Flowpatterns constructed by use of this model were compared with flow pulses recorded in anesthetized dogs in the left circumflex coronary artery with an electromagnetic flowmeter. A characteristic feature of the apparent input impedance of a coronary artery has been found experimentally and could be explained by the fact, that the myocardial contraction serves as an additional energy source within the coronary system. The possible usefulness and physiological importance of the application of analytical methods to the hemodynamics of the coronary arteries is discussed. [ABSTRACT FROM AUTHOR]