First Heart Sounds

Fourth Heart Sound Plus First Heart Sound

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.

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Position: Mitral
Chestpiece: Bell

Maneuver: Supine

Phonocardiogram

Cardiac Animation

Table of Contents

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