Second Heart Sound - Splitting Auscultation Reference

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heart lung sounds waveform synthetic


For heart sounds listen to the synthetic sound while reviewing this lesson.

This lesson covers physiologic and paradoxical splitting of the second heart sound.

The second heart sound (S2) is created by the closing of the aortic valve and the closing of the pulmonic valve. The difference in timing between the closure of the aortic and pulmonic valves creates a split second heart sound.

Careful analysis of the splitting and intensity of the second heart sound can indicate the presence of many cardiac abnormalities.

In this example splitting varies between zero and eighty milliseconds depending on the phase of the respiratory cycle.

In physiologic splitting the maximum separation between aortic and pulmonic components of the second heart sound occurs at peak inspiration.

In paradoxical splitting the maximum separation occurs at peak expiration.

Paradoxical splitting can occur with left bundle-branch block (LBBB) and aortic stenosis both of which cause the aortic valve closure to be delayed until after the pulmonic valve closure, reversing the normal sequence of events.

As you listen to this sound, observe the waveform. This is a graph of sound amplitude (loudness) on the vertical axis vs time on the horizontal axis.

Additional Listening Tips

S2: Splitting during inspiration.

Auscultation Method

The recommended patient position is supine
For this sound, use stethoscope's diaphragm The recommended auscultation position for the stethoscope is pulmonic

Relevant Courses

If you wish to review a complete mobile concerning Second Heart Sound - Splitting Auscultation Reference and related heart sounds, the modules(s) listed below may be useful. Each lesson includes text that explains the auscultatory sound and its clinical significance. The lesson also includes an audio track for playback. A waveform provides a great way to visualize the sounds. Finally, we also include an animation video. For heart sounds, the video illustrates heart muscle and valve movements along with blood flow. For lung sounds, the primary source of the sounds can be seen. Each module also includes a quiz.

Second Heart Sound - Splitting Auscultation Reference