nitrogen (countable and uncountable, plural nitrogens) ( 1 uncountable) A chemical element (symbol N) with an atomic number of 7 and atomic weight of 14.0067. ( 2 uncountable) Molecular nitrogen (N2), a colorless, odorless gas at room temperature.
Your primary care doctor may detect a heart murmur or other signs of heart valve disease. However, a cardiologist usually will diagnose the condition. A cardiologist is a doctor who specializes in diagnosing and treating heart problems. To diagnose heart valve disease, your doctor will ask about your signs and symptoms. He or she also will do a physical exam and look at the results from tests and procedures.
Pressure changes on either side of the valves cause them to open their flap-like doors (called cusps or leaflets) at just the right time, then close tightly to prevent a backflow of blood. There are 4 valves in the heart: tricuspid, pulmonary, mitral, and aortic. In the United States, surgeons perform about 106,000 heart valve operations each year. Nearly all of these operations are done to repair or replace the mitral or aortic valves. These valves are on the left side of the heart, which works harder than the right.