Coronary angiography is a procedure to check for any blocks in blood flow through the artery. When untreated, these blocks can cause heart diseases or heart attack. In a coronary angiography, angio test, or coronary angiogram test procedure, the doctor introduces a catheter with a contrast dye to visualise the blockages in the coronary arteries. After heart angiography the doctor plans a procedure to revive the normal blood supply to the heart so that it begins to work efficiently.