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 ...

Heart sounds are the noises made when heart valves close as blood moves through the heart. S1 and S2 are normal heart sounds. Other heart sounds, such as S3 and S4, are abnormal. The heart has ...

only a single heart sound is usually heard. However, in about 40% to 70% of normal individuals — as well as in certain cardiac conditions — a “split S1” sound can be appreciated.