The Aortic Sclerosis Murmur

1. What percentage of patients over age 50 have an easily audible aortic ejection murmur without valvular stenosis?

ANS: About 50%. Echoardioqrams have shown that many elderly patients have a septum that bends into the outflow tract, the so-called sigmoid septum (sigma = Greek S). This could create enough turbulence to mimic the murmur of aortic valve sclerosis (sclerosis = Greek "hard"). Therefore a more nonspecific terminology should be used. Since about 50% of patients over age 50 have the murmur especially if they are hypertensive, we should call this the "50 over 50" (50/50) murmur. However, if you eliminate patients with elevated blood pressure and ECG evidence of LVH, then only about 30% will have this murmur [4].

2. What are the causes of an innocent aortic ejection murmur besides a sigmoid septum?

ANS: There are several theories.

a. It is due to fibrosis, thickening, and often some calcification involving the bases of the aortic cusps. They do not open fully because of stiffness (aortic valve sclerosis). However, although they open enough to prevent any significant gradient across the orifice, there is enough narrowing to cause turbulence and an ejection murmur.

b. It is due to calcific spurs on the aortic ring, which may protrude into the bloodstream.

A slight but abrupt protuberance (e.g. a calcium spur) is capable of producing a murmur of considerable intensity.

c. It is due to atherosclerotic plaques in the ascending aorta, which may cause turbulence as the aortic stream strikes the roughened endocardium.

Note: a. The general condition alluded to by these theories is called aortic sclerosis.

b. If the valvular calcification that caused the sclerosis murmur becomes excessive, severe aortic valve obstruction may occur; this then becomes calcific aortic stenosis.

3. How loud can a murmur be that is due to aortic sclerosis?

4. What is the most important method of distinguishing by physical examination a loud murmur of aortic sclerosis from that of AS?

ANS: Palpation of the carotid will generally differentiate between the slow rise of AS and the normal rise of aortic sclerosis. However, an elderly patient with significant AS may have a normal rate of rise if his or her carotids are sclerotic.

Note: a. A reversed split S2 in the absence of LBBB suggests a significant gradient. If the murmur is so loud and long that it is difficult to hear S2 splitting clearly, use a pediatric diaphragm to soften the murmur. b. Bleeding from the right colon due to angiodysplasia occurs often enough in patients with AS to consider it a true association.

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Blood Pressure Health

Blood Pressure Health

Your heart pumps blood throughout your body using a network of tubing called arteries and capillaries which return the blood back to your heart via your veins. Blood pressure is the force of the blood pushing against the walls of your arteries as your heart beats.Learn more...

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