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Cardiovascular Physiology Concepts

Richard E. Klabunde, PhD

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Cardiovascular Physiology Concepts textbook cover

Click here for information on Cardiovascular Physiology Concepts, 2nd edition, a textbook published by Lippincott Williams & Wilkins (2011)


Cardiovascular Physiology Concepts textbook cover

Click here for information on Normal and Abnormal Blood Pressure, a textbook published by Richard E. Klabunde (2013)




Arterial and Aortic Pulse Pressure

As the left ventricle ejects blood into the aorta, the aortic pressure increases.  The greater the stroke volume, the greater the change in aortic pressure during ejection.  The maximal change in aortic pressure during systole (from the time the aortic valve opens until the peak aortic pressure is attained (see Cardiac Cycle) represents the aortic pulse pressure, which is defined as the systolic pressure minus the diastolic pressure. For example, if the systolic pressure is 130 mmHg and the diastolic pressure is 85 mmHg, then the pulse pressure is 45 mmHg.

Pulse Pressure = Systolic Pressure − Diastolic Pressure

arterial and aortic pulse pressure
The rise in aortic pressure from its diastolic to systolic value is determined by the compliance of the aorta as well as the ventricular stroke volume. In the arterial system, the aorta has the highest compliance, due in part to a relatively greater proportion of elastin fibers versus smooth muscle and collagen. This serves the important function of dampening the pulsatile output of the left ventricle, thereby reducing the pulse pressure (systolic minus diastolic arterial pressure). If the aorta were a rigid tube, the pulse pressure would be very high.  Because the aorta is compliant, as blood is ejected into the aorta, the walls of the aorta expand to accommodate the increase in blood volume. As the aorta expands, the increase in pressure is determined by the compliance of the aorta at that particular range of volumes. The more compliant the aorta, the smaller the pressure change during ventricular ejection (i.e., smaller pulse pressure) (see figure). Therefore, aortic compliance is a major determinant, along with stroke volume, of the pulse pressure.

stroke volume and aortic compliance determine pulse pressure

Summary:

RK Revised 03/29/2007



DISCLAIMER: These materials are for educational purposes only, and are not a source of medical decision-making advice.