First Heart Sounds

First Heart Sound plus Aortic Ejection Click Sounds

A single first heart sound (S1) followed by an aortic ejection click (AEC) can also mimic a split first heart sound. An AEC follows S1 by 50 milliseconds.

An aortic ejection click is caused by thickened aortic valve leaflets. This is commonly seen in a bicuspid aortic valve, a congenital abnormality where someone is born with two aortic valve leaflets instead of the normal three.

Listen carefully to the second sound of the pair. If it is an AEC it will have a shorter duration and a higher pitch than the first sound of the pair (S1).

The AEC is best heard at the Aortic valve area where splitting of S1 is not heard.

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The recommended auscultation position for the stethoscope is the Aortic position. For this sound, use stethoscope's Diaphragm.

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The recommended patient position is Sitting

Phonocardiogram

This waveform plots sound amplitude on the vertical axis against time on the horizontal axis.

Heart Animation

Lessons

1	First Heart Sound - Loud
2	First Heart Sound (Minimally Split)
3	First Heart Sound (Markedly Split)
4	First Heart Sound - Decreased Intensity
5	Fourth Heart Sound Plus First Heart Sound
6	First Heart Sound plus Aortic Ejection Click

Practice Drill

Listening Tips
A synopsis of important sound features and timing for this abnormality.
Systole: High pitched sound, early in systole, short duration.

CaseID	43
CourseID	23
CourseCaseOrder	6
ID	31