Blood Pressure and Flow in the Ascending Aorta of Conscious Dogs

Blood pressure and flow were measured in the root of the aorta in conscious dogs. Aortic flow was varied by pacing the heart and by injecting myocardial stimulants into a coronary artery. The calculated aortic input impedance was capacitative in the lower frequency range and inductive above 3 to 6 cycles/sec. Graphical analysis also showed that aortic pressure rose by 50% of the pulse pressure when less than 1 ml. of the stroke volume had been ejected from the heart.