Oxygen Consumption in Myocardium during Experimentally-induced Aortic Stenosis

We investigated changes in oxygen consumption of the myocardium with respect to increase in subvalvular aortic stenosis, in 10 thoractomized mongrel dogs under anesthesia. A balloon catheter was advanced from the carotid artery and positioned under the aortic valve. The balloon was inflated by saline solution to produce subvalvular stenosis. Compared to pre-stenotic level the oxygen consumption remained almost unchanged at left ventricular pressure (PLV) and aortic pressure (PAo) gradient of up to 20 mmHg but showed about 15% increase at 40 mmHg and about 30% increase at 60 mmHg.. Coronary blood flow (CBF) also remained almost unchanged at pressure gradient of up to 20 mmHg but was decreased about 10% at 40 mmHg and about 20% at 60 mmHg