First Heart Sounds

Fourth Heart Sound Plus First Heart Sound Sounds

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Certain heart sound configurations mimic a split first heart sound.

One of these conditions is a fourth sound gallop (S4) plus a first heart sound (S1). Since the S4 occurs just before the S1 it is easy to confuse a S4/S1 with a split S1.

An S4 is lower frequency than an S1. To differentiate between a S4/S1 and a split S1, listen carefully to the frequency of the initial sound of the pair. If it is lower in frequency than the second sound it is an S4. If the two sounds are the same it is a split S1.

Fourth Heart Sound Plus First Heart Sound

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

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The recommended patient position is Supine

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.
Diastole: S4 present - a low pitched sound.

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