Tricuspid insufficiency (TI), a valvular heart disease also called tricuspid regurgitation (TR), refers to the failure of the heart's tricuspid valve to close properly during systole. This defect allows the blood to flow backwards, reducing its efficiency. Regurgitation may be due to a structural change of components of the tricuspid valve apparatus, a lesion can be primary (intrinsic abnormality) or secondary (right ventricular dilatation).