Second Heart Sounds

Second Heart Sound and Late Systolic Click Sounds

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Certain heart sound configurations mimic a split second heart sound.

One of these conditions is a late systolic click plus a single second heart sound (S2). Since the late systolic click occurs just before the S2 it is easy to confuse the two with a split S2.

Listen carefully to the two sounds. If the first of the pair is of higher frequency and shorter duration than the second, it is a late systolic click followed by a single second heart sound.

Another way of distinguishing a late systolic click from a split S2 is to move the stethoscope head to the pulmonic area. The late systolic click will disappear and you will only hear the single S2.

A late systolic click is caused by degeneration of the mitral valve leaflets. This degeneration causes the closing of the leaflets to make a "clicking" sound during late systole.

On the Anatomy tab you will see prolapse of the anterior lateral mitral valve leaflet which is the cause of the late systolic click.

Second Heart Sound and Late Systolic Click

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The recommended auscultation position for the stethoscope is the Mitral 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	Second Heart Sound - Physiologically Split #2
2	Second Heart Sound with Persistent Splitting
3	Second Heart Sound with Fixed Splitting
4	Second Heart Sound: Fixed Splitting, Increased Aortic Intensity
5	Second Heart Sound: Fixed Splitting, Decreased Aortic Intensity
6	Second Heart Sound and Late Systolic Click
7	Second Heart Sound and a Tumor Plop
8	Opening Snap and Second Heart Sound

Practice Drill

Listening Tips
A synopsis of important sound features and timing for this abnormality.
Systole: Higher pitched click late in systole with short duration.

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