Second Heart Sound - Splitting C31
Second Heart Sound - Splitting C31
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.Auscultation Sounds
Position
The patient's position should be supine.
Listening Tips
S2:Splitting during inspirationWaveform (Phonocardiogram)
Observe
//embedding heart animation
Authors
These authors contributed the audio recordings and text found in this reference guide: Jon Keroes, MD,Diane Wrigley, PA, and David Lieberman.Medically reviewed by Dr. Barbara Erickson, PhD, RN, CCRN.
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