Let us together analyze the contour of our patient's carotid arterial pulse. We'll again use the cotton swab and observe the tip of the cotton swab's excursion and note that the upstroke of this patient's carotid arterial pulse is rapid rising. [Cut-away]
What is the cause of a rapid rising carotid arterial pulse? A hyperdynamic circulation associated with an enhanced ventricular contractility. The causes may be non cardiac or cardiac. Non cardiac causes include fever, anemia, thyrotoxicosis. Cardiac causes include aortic valve regurgitation, mitral valve regurgitation, regurgitant lesions of the left side, and also may include a shunt lesion - patent ductus arteriosus - that may also have a rapid rising carotid impulse. The mechanism in the case of the cardiac lesions is a reduced resistance to the ejection of blood from the left ventricle.
Normal vs. Hyperkinetic Graphics
By comparing the graphic of a normal patient to that of our patient, we can appreciate our patient's rapidly rising carotid pulse. An hyperkinetic pulse has a quick upstroke that is due to an enhanced velocity of contraction associated with decreased resistance to emptying. The large amplitude most often reflects an increase in stroke volume.