The Effect of Cycle Length on the Time of Occurrence of the First Heart Sound and the Opening Snap in Mitral Stenosis

Abstract

Phonocardiography is often more valuable than electrocardiography in timing mechanical events in the cardiac cycle. This study shows that the opening and closing of the mitral valve are related to the length of the previous heart cycle as demonstrated by the variations occuring in auricular fibrillation. These variations in valve action are controlled by the pressure gradient between left auricle and ventricle.