REGISTRATION AND INTERPRETATION OF NORMAL PHASIC INFLOW INTO A LEFT CORONARY ARTERY BY AN IMPROVED DIFFERENTIAL MANOMETRIC METHOD

Abstract

A method is described for continuous optical registration of the instantaneous rate of inflow into a coronary artery. This involves shunting the blood from the aorta to the coronary artery through a short external circuit containing an orifice (or other device) connected with a differential manometer. The left coronary inflow curves so obtained demonstrate that beginning at the onset of isometric contraction there is a rapid retardation of flow but that with the rise of aortic pressure during ejection the inflow rapidly accelerates, reaching a peak during the middle of the rise of aortic pressure and then declining to a more or less constant rate of inflow during the latter part of systole. Following the incisura there is again a rapid acceleration, the inflow reaching a peak early in diastole and then declining with the progressive fall of aortic pressure in diastole. The inflow records are complicated by vol. elastic effects due to the cyclic rise and fall of aortic pressure and by a compressor action of ventricular systole. However, the rate of inflow at the end of diastole just preceding isometric contraction, can probably be used as an index of intramural flow during diastole, while the rate of inflow during the brief interval at or just preceding the onset of protodiastole, i.e., at the peak of the peripheral coronary pressure curve, can probably be used as an index of the systolic rate of intramural flow. In almost all instances the systolic intramural flow so measured is of sizable magnitude. The rate of intramural flow per mm. of differential pressure is greater during systole than during diastole. Simultaneous measurement of aortic pressure and rate of intramural flow indicates that the resistance to blood flow existing during the latter part of diastole is increased from 2 to 4 fold during systole. The total flow may be detd. from the moment to moment flow curve by appropriate procedures.