S1 Heart Sound Page
Welcome to the S1 heart sound page. On this page we provide a definition, sample heart sounds and links to the training lessons available on this site.
What is an S1 Heart Sound?
S1 heart sound is a low frequency sound, occurring at the beginning of systole. S1 can be best heard over the apex, using a stethoscope's bell or diaphragm. The first heart sound is caused by turbulence created when the mitral and tricuspid values close. S1 and S2 heart sounds are often described as lub - dub.
S1 & S2 Heart Sounds Audio
S1 and S2 Normal
Click to play.
S1 Heart Sound Caused By
The S1 heart sound is caused by blood flow turbulence when mitral and tricuspid valves close at the start of systole.
Best Heart Position During Auscultation
Because S1 heart sounds occur when the mitral and tricuspid valve close, the best heart is locations for the stethoscope chestpiece are at the tricuspid (left lower sternal border) and mitral (cardiac apex) locations.