: chorda tendinea) or tendinous cords, colloquially known as the heart strings, are inelastic cords of fibrous connective tissue that connect the papillary muscles to the tricuspid valve and the mitral valve in the heart.

[1][2] The chordae tendineae connect the atrioventricular valves (tricuspid and mitral), to the papillary muscles within the ventricles.

Along with the opening of the coronary sinus and the septal cusp of the tricuspid valve, Koch's triangle is made up.

[5] During atrial systole, blood flows from the atria to the ventricles down the pressure gradient.

The chordae tendineae prevent this prolapse by becoming tense, which pulls on the flaps, holding them in a closed position.