The heart has four chambers and four valves; the valves open and close like one-way gates to separate the heart chambers and control the flow of blood into and out of the heart. The top two chambers of the heart are the right and left atrium. The bottom two chambers are the right and left ventricle. The large blood vessels that bring blood to the heart are the superior vena cava, the inferior vena cava, and the pulmonary veins; the large vessels that carry blood out of the heart are the aorta (to the body) and the pulmonary artery (to the lungs).

The tricuspid valve controls the blood moving from the right atrium to the right ventricle. The blood is then pumped out of the right ventricle through the pulmonary valve into the pulmonary artery to the lungs, where it picks up oxygen before returning to the heart through the pulmonary veins into the left atrium. The mitral valve allows blood to move from the left atrium to the left ventricle, and the aortic valve controls the blood leaving the left ventricle and going to the body.

When heart valves are working correctly, they respond to changing pressures within the heart chambers by opening and closing. When open, the valves allow blood to flow freely. When properly closed, the valves prevent blood from flowing back to its previous location; when the valves don’t close properly, however, the blood can move backward through the valve. This is called regurgitation. The symptoms of restrictive valvular heart disease may include shortness of breath and tiredness or fatigue, which is caused by the heart not pumping blood properly through the body.