The S1 and S2 heart sounds are two of the most commonly heard heart sounds and are often referred to as the "lub-dub" sounds of the heart.
Here’s a for S1 and S2 heart sounds — something not just acoustic, but capturing underlying physiological or mechanical significance. s1 s2 heart sounds
The intensity and timing of S1 and S2 heart sounds can vary under different physiological conditions: The S1 and S2 heart sounds are two