During cardiac catheterization, a doctor inserts a catheter (long, thin, flexible tube) into blood vessel in the patient’s arm or leg. Once inserted, the catheter is guided by the physician toward the heart. This procedure allows the physician to study how well the heart pumps blood as well as allows an examination of the coronary arteries (the blood vessels that supply blood to the heart muscle) and the heart valves. This procedure is also often referred to as a coronary angiography, angiogram, cardiac cath, and heart cath.