Failure of the mitral valve of the heart to close completely causing blood to flow backward from left ventricle to left atrium during ventricular contraction.
Faulty sealing of the bicuspid valve, causing backflow of blood into the atrium from the ventricle.
Failure of the mitral valve of the heart to close tightly, causing it to leak (regurgitate), decreasing the flow of blood into the body. To compensate, the ventricle pumps harder, and over time it enlarges to compensate. Eventually, the ventricle begins to fail, and lung congestion can result from the pooling of blood in the left atrium. A type of rapid heartbeat known as atrial fibrillation can also develop, and a blood clot may form in the atrium, travel through the blood¬ stream, and lodge in a blood vessel.