Effective Closure of the Mitral Valve without Atrial Systole

Abstract

There has been considerable dispute concerning the role of atrial contraction in the closure of the atrioventricular valves. Selective angiocardiograms with left ventricular [see figure in the PDF file] opacification in 43 patients having a variety of arrhythmias that resulted in the absence of atrial systole, or in an abnormal temporal relationship between atrial and ventricular contractions, revealed no evidence of mitral regurgitation. From this observation it is concluded that a properly timed atrial contraction is not always essential for effective closure of the mitral valve in man.