Prosthetic heart valve. Trio of coloured 3D CT (computed tomography) scans of a 70-year-old patient's chest. The front of the chest is at left, with the view panning from oblique (left image) to profile (right image). The prosthetic heart valve (white) is seen at centre, where the aorta (pink) meets the heart (blue, lower centre). The stitches used to close the chest are seen at upper left. The heart valves prevent backflow of blood in the heart. If they start to fail, a condition known as incompetence, then the patient may not get enough oxygenated blood. This leads to shortness of breath, chest pain and possibly a heart attack. The replacement valve here is artificial, but some can be from donors or even from other animals, usually a pig.