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 ...

When normal laminar blood flow within the heart ... Remember that systole occurs between the S1 and S2 heart sounds, whereas diastole occurs between S2 and S1. With the knowledge of the possible ...