One of the most common serious afflictions in modern society is heart disease. This general label encompasses many different abnormal conditions, including congenital heart defects (many of which can be repaired surgically), diseases of the pericardium (the tissue surrounding the heart muscle), and diseases affecting the heart muscle itself (the myocardium). Physicians can often detect or predict heart problems by measuring the rate of the heartbeat (called the pulse) and by taking the patient’s blood pressure. Another important diagnostic tool is the electrocardiogram (EKG), a record of the electrical activity of the heart, which can reveal abnormal cardiac rhythm and myocardial damage. When heart disease is suspected and more detailed information is needed, an angiogram is ordered. This series of X-ray films (taken after the injection of a radiopaque substance) defines the size and shape of various veins and arteries.