First Heart Sound Page
Welcome to the first 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 First Heart Sound?
The first heart sound is a low frequency sound, occurring at the beginning of systole. First heart sounds can be best heard over the apex, using a stethoscope's bell or diaphragm. The first heart sound is causes by turbulence created when the mitral and tricuspid values close. In normal adults, S1 and S2 heart sounds are heard, often described as lub - dub.
Listen to First Heart Sound
First and Second Heart Sounds
Normal first and second heart sounds.