Heart disease. Coloured X-ray angiogram of the heart of a patient who has suffered a suspected heart attack (myocardial infarction, M.I.). The left coronary artery (blue), which supplies the heart muscle with oxygenated blood, is shown. The angiogram reveals extensive stenosis, or narrowing, of the blood vessels. A thrombus (blood clot, curved swelling at centre right) has blocked the flow to the lower anterior interventricular artery (white, lower right). Both of these conditions restrict the blood supply to the heart muscle, which can lead to an M.I., where a portion of the muscle dies (pink). A radio-opaque contrast medium highlights the vessels on the X-ray.