Is The S1 Heart Sound Free - What

The S1 heart sound, colloquially known as the is the acoustic signal marking the beginning of ventricular systole —the phase where the heart contracts to pump blood.

| Feature | S1 (“lub”) | S2 (“dub”) | |---------|------------|------------| | | Closure of mitral & tricuspid valves | Closure of aortic & pulmonic valves | | Timing | Beginning of systole (ventricular contraction) | Beginning of diastole (ventricular relaxation) | | Best heard at | Heart apex (mitral area) | Heart base (aortic/pulmonic areas) | | Pitch | Slightly lower than S2 | Higher pitch | what is the s1 heart sound