Two sounds made by the heart, which represent each cardiac cycle when heard through a stethoscope.
A representation of the normal heart sounds as heard through the stethoscope. Lubb (the first heart sound) coincides with closure of the mitral and tricuspid valves; dupp (the second heart sound) is due to closure of the aortic and pulmonary valves.
The two sounds heard in auscultation of the heart technically referred to as S1 (“lubb”) and S2 (“dupp”). The pause following the sounds is slightly longer than that between the two sounds.