It’s produced by the closure of the Atrioventricular (AV) valves —the Mitral and Tricuspid valves. These valves slam shut to prevent blood from flowing back into the atria when the ventricles contract. Sound: Low-pitched and slightly longer in duration than S2.
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? s1 heart sounds
Would you like a similar review of S2, splitting patterns, or murmurs? It’s produced by the closure of the Atrioventricular