S1 Heart Sounds -

The first heart sound, , is the familiar "lub" in the heart’s "lub-dub" rhythm. It signals the official start of systole —the phase when your heart contracts to pump blood to the rest of the body. 💓 The Basics: What is S1?

The , colloquially known as the "lub" of the classic "lub-dub," is the first major acoustic event in the cardiac cycle. It is primarily a high-pitched sound that marks the transition from mechanical diastole (rest) to ventricular systole (contraction). Physiology: What Produces S1?

You’ll hear S1 loudest at the apex of the heart (5th intercostal space, mid-clavicular line). 🩺 Clinical Pearls S1 Heart Sound - Learn How to Auscultate (Part 8) s1 heart sounds

Here are some key points about S1 heart sounds:

As the ventricles begin to contract, the pressure within them rapidly rises. When this ventricular pressure exceeds the pressure in the atria, the AV valves slam shut to prevent the backflow of blood. This mechanical closure, combined with the subsequent tensing of the chordae tendineae and the vibrations of the ventricular walls, creates the audible "lub" heard during auscultation. Heart Sounds and Murmurs - UTMB The first heart sound, , is the familiar

| Feature | S1 | S2 | |---------|----|----| | Timing | Start of systole | End of systole | | Best heard | Apex (mitral/tricuspid) | Base (aortic/pulmonic) | | Relation to carotid pulse | with upstroke | Follows pulse | | Effect of inspiration | Splits slightly (RBBB → wide) | Splits physiologically |

Would you like a similar review of S2, splitting patterns, or murmurs? The , colloquially known as the "lub" of

The S1 sound is often described as a "lub" and is the first of the two main heart sounds that can be heard with a stethoscope during auscultation.

Abnormalities in S1 heart sounds can indicate underlying cardiac issues, making it an essential component of cardiac assessment.