a sharp, clicking sound heard during cardiac systole; when heard in early systole it is usually an ejection sound; in late systole the click usually signifies mitral insufficiency, as in the dysfunction of the mitral valvular apparatus when it prolapses into the left atrium during systole (see Barlow syndrome); rarely may also be due to pleuropericardial adhesions or other extracardiac mechanisms.
Etymology: Gk, systole, contraction; Fr, cliqueter, to click
a sharp, clicking sound heard in mid- or late systole and believed to originate from the abnormal motion of the mitral valve. The most frequent cause of systolic clicks is prolapse of a mitral valve leaflet, in which case there may be an associated late systolic regurgitant murmur, sometimes called the click-murmur syndrome. Compare ejection click.