It goes round and round
The blood always flows from the atria to the ventricles. If it flows in the reverse direction, from ventricles to the atria it is a sign of a major heart disease. The other two valves in the heart are at the root of the aorta (aortic valve) and at the root of the pulmonary artery (the pulmonary valve) If any one or more of these four valves are diseased, the heart will not function well and its efficiency will decease.