First Heart Sounds

First Heart Sound (Minimally Split) Sounds

On occasion the first heart sound can be made up of two separate sounds separated by a very small interval (20-30 milliseconds).

The Mitral component (caused by closure of the Mitral valve) comes first and is louder than the Tricuspid component (caused by closure of the Tricuspid valve).

A minimally split first heart sound is a normal variation of the first heart sound.

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

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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.
S1: Minimal splitting.

CaseID	39
CourseID	22
CourseCaseOrder	2
ID	27