second heart sound


sec·ond heart sound (S2),

the second sound heard on auscultation of the heart; signifies the beginning of diastole and is due to closure of the semilunar valves. Synonym(s): second sound

second heart sound

Cardiology A heart sound that corresponds to closure of the semilunar–pulmonary and aortic valves, which is a short, higher pitched “dubb”. See First heart sound, Fourth heart sound, Third heart sound.

sec·ond heart sound

(S2) (sek'ŏnd hahrt sownd) The second sound heard on auscultation of the heart; signifies the beginning of diastole and is due to closure of the semilunar valves; auscultated at base of heart.