S1 and S2 are the normal heart sounds you hear when the heart valves close. Heart murmurs are extra sounds that can be heard during systole, diastole, or as a continuous sound. S3 and S4 are abnormal ...
S1 is the first heart sound that doctors can hear using a stethoscope. The vibrations that occur when the mitral and tricuspid valves in the heart close produce the S1 sound. There are two common ...