Bacteria: Germs that can lead to disease.
Bacterial Endocarditis: A bacterial infection of the lining of the heart’s chambers (called the endocardium) or the heart’s valves.
Balloon Catheter: A long tube-like device with a small balloon on the end that can be threaded through an artery. Used in angioplasty or valvuloplasty.
Balloon Valvuloplasty: A procedure to repair a heart valve that is not working properly. A balloon-tipped catheter is threaded through an artery and into the heart. The balloon is inflated to open and separate any narrowed or stiffened flaps (called leaflets) of a valve. The catheter and deflated balloon are removed after the procedure.
Beta-Blocker: An antihypertensive medicine that limits the activity of epinephrine, a hormone that increases blood pressure.
Biopsy: The process by which a small sample of tissue is taken for examination.
Blalock-Taussig Procedure: A shunt between the subclavian and pulmonary arteries used to increase the supply of oxygen-rich blood in “blue babies” (see below).
Blood Clot: A jelly-like mass of blood tissue formed by clotting factors in the blood. Clots stop the flow of blood from an injury. Clots can also form inside an artery when the artery’s walls are damaged by atherosclerotic buildup, possibly causing a heart attack or stroke.
Blood Pressure: The force or pressure exerted by the heart in pumping blood; the pressure of blood in the arteries.
Blue Babies: Babies who have a blue tinge to their skin (cyanosis) resulting from insufficient oxygen in the arterial blood. This condition often indicates a heart defect.
Body Mass Index (BMI): A number that doctors use to determine the risk of cardiovascular disease created by a person being overweight. BMI is calculated using a formula of weight in kilograms divided by height in meters squared (BMI =W [kg]/H [m2]).
Brady Pacing: A method of treating a slow or irregular heartbeat by periodically stimulating the heart with small electrical pulses.
Bradycardia: A slow heartbeat, typically less than 60 beats per minute. It may be caused by the sinoatrial node not working properly, or by a condition called heart block.
Bruit: A sound made in the blood vessels resulting from turbulence, perhaps because of a buildup of plaque or damage to the vessels.
Bundle Branch Block: A condition in which parts of the heart’s conduction system are defective and unable to conduct the electrical signal normally, causing an irregular heart rhythm (arrhythmia).
Bypass: Surgery that can improve blood flow to the heart (or other organs and tissues) by providing a new route, or “bypass,” around a section of clogged or diseased artery.