Relation Between Coronary Blood Flow and Myocairdial Oxygen Consumption
Experiments were done in the isolated supported heart preparation to ascertain whether a change in coronary blood flow would induce a change in myocardial O2 consumption if the activity of the heart (aortic pressure, heart rate and stroke volume) was controlled. Over a wide range of coronary blood flows, the O2 consumption did not vary under such circumstances. If the coronary flow was restricted to levels which produced an unequivocal deteriration of ventricular performance, a modest decrease in O2 consumption was sometimes observed.
Reciprocal type experiments were also performed. In these, coronary flow was held constant or nearly so while varying the activity of the heart markedly. Under these circumstances the myocardial O2 consumption did vary directionally with the amount of ventricular myocardial tension developed insofar as this was indicated by the tension-time index.
Data were also obtained suggesting that ventricular end diastolic fiber length is not of itself a major determinant of myocardial O2 consumption.
- Received July 11, 1963.
- © 1963 American Heart Association, Inc.