Auditory vibrations of varying intensity (loudness), frequency (pitch), quality, and duration noted during auscultation of the thorax as part of the examination of the cardiovascular system. (ACC-AHA)

The sounds heard over the cardiac region produced by the functioning of the heart. There are four distinct sounds: the first occurs at the beginning of SYSTOLE and is heard as a "lubb" sound; the second is produced by the closing of the AORTIC VALVE and PULMONARY VALVE and is heard as a "dupp" sound; the third is produced by vibrations of the ventricular walls when suddenly distended by the rush of blood from the HEART ATRIA; and the fourth is produced by atrial contraction and ventricular filling.

Cardiovascular diseases continue to be the leading cause of morbidity and mortality worldwide. One of the first steps in evaluating the cardiovascular system after detailed history taking is physical examination.