The main normal heart sounds are the S1 and the S2 heart sound. The S3 can be normal, at times, but may be pathologic. A S4 heart sound is almost always pathologic. Heart sounds can be described ...

A third heart sound, or S3, is a low-frequency, extra heart sound that may be heard with a stethoscope right after the normal S1 and S2 heart sounds. S1 and S2 are the "lub-dub" sounds of a ...

The fourth heart sound (S4), also known as the “atrial gallop,” occurs just before S1 when the atria contract ... overly compliant LV will produce a S3 heart sound. A S4 heart sound can ...

Besides S1, there is also a second heart sound (S2), which is the "dub" of a heartbeat. In some cases, extra heart sounds like a third (S3) or fourth (S4) sound or brief, vibratory sounds (heart ...