Dependency of transcoronary circulatory transport function on coronary perfusion pressure and flow.

Transcoronary circulatory transport function was computed from the dye-dilution curves recorded simultaneously at the entrance (aortic root) and exit (coronary sinus) of the coronary circulation after the injection of dye bolus into the femoral vein in open-chest dog. The effect of coronary perfusion pressure and flow on the first (delta-t) and second (deltapi2) moments of the transport function was examined before and during intra-aortic angiotensin infusion. It was observed that the relative dispersion (deltapi2 1/2/delta-t) in the canine coronary circulation is the largest among the organ-circulations that have been examined by the investigators, suggesting that cardiac wall is highly heterogeneously perfused, and that the relative dispersion was variable depending on the coronary perfusion pressure and flow. It is concluded that sole measurement of the moment of transcoronary transport function such as -t cannot be a reliable indicator of the coronary circulatory disturbances. The underlying mechanisms for the dependency of the relative dispersion on the perfusion was discussed.