- BNP (b-type or brain natriuretic peptide)
- A protein that is released by the muscle tissue of the heart, particularly the ventricles; the amount that is released increases as the heart is stretched or strained.
- Branching airways in the lungs that carry air from the trachea to the alveoli
- Bubble study
- A specialized echocardiogram that looks for holes between the right and left sides of the heart by injecting bubbles (agitated saline) into the bloodstream and watching to see if they cross from the one side of the heart to the other