Mitral regurgitation, also known as mitral regurgitation, and mitral valve insufficiency. We know that the heart has four chambers, the left and right atria, with the left side being the main one. There is a door between the atria and the ventricles. Through this door, blood can flow. Normally, during the diastole phase of the heart (ventricles) blood flows from the atria to the ventricles and during systole this door closes and no blood flows. The design of this one-way valve, similar to a pump, allows a constant flow of blood from the atria to the ventricles through the beat-to-beat contraction of the heart, ensuring our normal blood circulation. This door between the left atrium and the ventricle is called the mitral valve. The mitral valve, as the name implies, is a two-tip valve, somewhat similar to our lips, which can be opened or closed. When the blood flows during diastole, it is similar to when we exhale outward, and during systole it is similar to when we walk against a cold wind and close our mouths to keep the cold wind out. Normally, there is no blood returning to the left atrium from the mitral valve during systole. For various reasons, blood flows back from the left ventricle to the left atrium during systole, and this is called mitral regurgitation.