During coronary angiography, a catheter is passed through an artery to the heart, a dye is passed through it and X-ray images of the heart are taken. This test is done to see how blood flows through the arteries in the heart, as stated by the National Institutes of Health's MedlinePlus. It is performed to check conditions, such as angina, heart failure and aortic stenosis.
This test may be done during an emergency or it may be scheduled in advance allowing enough time to prep. A doctor will provide specific requirements for preparation. Eating or drinking anything is not recommended on the night before the test. The doctor may want to see any current medication a person is using in their original bottles. Diabetics may need to inquire the doctor for more information on the use of medication prior to the test, as stated by Mayo Clinic.
During the test, a mild sedative is given to the patient to attain relaxation. The groin or the arm is cleaned and numbed using a local anesthetic. The doctor passes a hollow tube called a catheter through the artery until it gets to the heart. A special dye is administered through the catheter to the artery. The dye helps to detect any blockage in the flow of blood. This procedure may take 30 to 60 minutes.