The Humming Systolic Ejection Murmur

1. What adjectives have been used to describe the quality, or timber, of the humming (innocent) ejection murmur that is found in children? What eponym has been used for it?

ANS: It has been described as a buzzing, vibratory, twanging, moaning, or groaning murmur. It has also been called Still's murmur, after the British author of a pediatric textbook published in 1918, who described it as a "twanging string" murmur.

2. Why was it thought by some to be an aortic murmur?

ANS: A fine vibration can sometimes be recorded on the carotid tracing, and the aortic root is thought by some to be relatively narrow in some of these patients.

3. What does the humming or vibratory quality of the murmur tell you about the prognosis?

ANS: It strongly suggests that the murmur is innocent and will probably (but not always) disappear after puberty.

4. Where is the humming murmur usually heard best?

ANS: Although it is best heard between the apex and the left sternal border, it is surprising how widespread it is and how difficult it is to localize it.

The regular vibrations on this phonocardiogram of a humming systolic murmur (SM) tell you that the murmur has a musical quality. The peak of the crescendo occurring in the first third of systole tells you that the gradient across the semilunar valve is probably trivial.

5. What suggests that it is a form of "flow" ejection murmur and is not due to obstruction?

ANS: a. The murmur is never louder than grade 3/6, and often disappears when the subject stands.

b. The murmur is usually short and reaches its peak early.

c. It is often associated with a venous hum (see Chapter 14).

d. It consists mostly of low and medium frequencies, i.e., between 75 and 160 cps. A murmur that is relatively low in pitch suggests that it is due mostly to flow with very little gradient.

Note: These humming murmurs may become as long as important murmurs in the presence of further increases blood flow, such as that occurring with high fever or severe anemia.

6. What suggests that this murmur may actually be a "twanging string" murmur as originally described by Still.

ANS: Most children with this murmur have a threadlike false tendon, over 60% of which stretches across the outflow tract of the left ventricle.

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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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