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Normal First and Second Heart Sounds Lesson

Virtual Auscultation

patient torso with stethoscope chestpiece

patient position during auscultation
The patient's position is supine.

Lesson

This is a normal first and second heart sound at 60 beats per minute. You are auscultating at the Mitral valve area (Apex). The first heart sound has slightly greater intensity than the second

This page presents normal first and second heart sounds with a heart rate of 60 bpm. Auscultate these sounds at the mitral valve area (apex) or tricuspid area. Often the first heart sound will be louder than the second heart sound.

The first heart sound is produced by the closing of the mitral and tricuspid valve leaflets. The mitral sound (M1) typically occurs before the tricuspid sound (T1). T1 and S1 splitting can be best heard at the tricuspid location. If M1 and T1 are separately distinguished, this is called an S1 split. S1 splitting is common in children. An S1 split can be associated with EKG-related abnormalities such as right bundle branch block, premature ventricular contractions, or ventricular tachycardia in adults.

The second heart sound is produced when the aortic and pulmonic valve leaflets close. S2 splitting will be presented in the next module.

Waveform




Heart Sounds Video

The first heart sound is produced by the closing of the mitral and tricuspid valve leaflets. The second heart sound is produced by the closing of the aortic and pulmonic valve leaflets.


Authors and Sources

Authors and Reviewers

Sources

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