tricuspid valve prolapse (MONDO_0007001) is abnormal protrusion of one or more of the leaflets of tricuspid valve into the right atrium during systole. This allows the backflow of blood into right atrium leading to tricuspid valve insufficiency; systolic murmurs. Its most common cause is not primary valve abnormality but rather the dilation of the right ventricle and the tricuspid annulus. Also known as: tricuspid valve prolapse (disease).