a result, the lower-frequency components of the heart sounds are
attenuated, whereas the higher frequencies are still well heard.
This important maneuver of being able to diminish the intensity of low-
pitched sounds, by pressure on the bell has several implications and
applications:
a. To hear faint, low-pitched sounds, the examiner must
apply the bell lightly to the chest wall.
b. By noting what happens to a sound or murmur when the
bell is first applied lightly, and then with pressure, the
examiner can judge, to a certain degree, the pitch of a sound
or murmur.
c. The high-pitched systolic murmur of mitral regurgitation is
less likely to be affected by pressure than medium-pitched,
innocent systolic murmurs.
d. With pressure, the faint, high-pitched, systolic murmur of
mitral regurgitation is less affected than the first heart sound,
and the masking effect of the first heart sound is thus
diminished. The same is true of the high-pitched, early
diastolic murmur of aortic regurgitation and accentuated
second heart sound.
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