Markedly Split First Heart Sound Lesson #661

patient thorax when auscultating by stethoscope

patient position during auscultation
The patient was supine during auscultation.


Splitting of the first heart sound is audible when the split interval is 50 milliseconds or higher. Auscultation is best performed at the tricuspid area to observe such splitting sounds. When the chestpiece is shifted to the apex, the mitral component of the split heart sound becomes louder. Markedly split first heart sounds is an auscultatory indication of premature ventricular contractions or right bundle branch block



Markedly Split First Heart Sound

Authors and Sources

Authors and Reviewers


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