the best cardiac centers in yelahanka Heart Valves Heart valves open when the heart pumps to allow blood to flow forward, and close quickly between heartbeats to make sure blood does not flow backward. Any problem with this normal flow will make it difficult for the heart to effectively pump the blood where it needs to go. The tricuspid valve sits between the right upper chamber (right atrium) and the right lower chamber (right ventricle). The tricuspid valve directs blood flow from the right upper chamber to the right lower chamber. The pulmonary valve directs blood flow from the right lower chamber (right ventricle) into the pulmonary artery, which splits into two arteries so that the blood from the body can get to both lungs. The mitral valve sits between the left upper chamber (left atrium) and left lower chamber. The mitral valve directs blood flow from the left upper chamber into the left lower chamber. The aortic valve directs blood from the left lower chamber (left ventricle) into the aorta. The aorta is the major blood vessel that leads from the left lower chamber to the rest of the body.