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 ...
An S4 heart sound is a low-pitched sound that occurs toward the end of the diastole. In some cases, an underlying health condition, often one affecting the left ventricle, may cause the S4 heart sound ...