During auscultation (listening to the heart with a stethoscope), the S1 sound is best heard at the apex of the heart. This location coincides with the mitral valve, which is the primary contributor to the S1 sound.
Here’s what S1 signifies:
Valve closure: S1 is primarily caused by the closing of the mitral valve (M1) and tricuspid valve (T1) at the beginning of ventricular systole (contraction).
“Lub” of “lub-dub”: S1 is often described as the “lub” in the classic “lub-dub” lub-dub heart sound sequence.
So, hearing a clear S1 at the apex indicates proper closure of the mitral valve and the beginning of the heart’s squeezing phase.
During auscultation (listening to the heart with a stethoscope), the S1 sound is best heard at the apex of the heart. This location coincides with the mitral valve, which is the primary contributor to the S1 sound.
Here’s what S1 signifies:
So, hearing a clear S1 at the apex indicates proper closure of the mitral valve and the beginning of the heart’s squeezing phase.