Ruptured chordae tendinae

Introduction

Chordae tendinae are fibrous structures of connective tissue that attach the cusps of the mitral and tricuspid valvular leaflets to the papillary muscles of the ventricular walls of the cardiac muscle. Their function is to support the leaflets of the atrioventricular valves and prevent the leaflets from everting and prolapsing.

In atrial systole, blood flows from the atria to the ventricles passively down the pressure gradient, and the chordae tendinae are relaxed because the valve leaflets are open at this time. During ventricular systole, the increased blood pressure in both ventricles push the atrioventricular valves to close simultaneously preventing backflow of blood to the atria, and the contraction of thick muscular walls of the ventricles help to support that. Since the blood pressure in the atria is lower than the pressure in the ventricles, the valve leaflets are sucked into the atria during ventricular systole. The chordae tendinae prevent the prolapse of the valves into the atria by the tensing of the papillary muscles which pull on the chords, thus holding the atrioventricular valves in a closed position for the duration of ventricular systole.

Chordae tendineae are comprised of approximately 80% collagen and 20% elastin and endothelial cells.