The mitral valve is an important structure within the left ventricular system; it serves as the necessary channel for blood from the left atrium to enter the left ventricle. Normally, this channel allows for unidirectional flow. However, when mitral valve insufficiency occurs, blood flows back from the left ventricle to the left atrium. This leads to an increase in cardiac work, reduces the efficiency of the heart’s function, and causes hypertrophy due to overuse of the left ventricle. When the mitral valve closes to a certain extent, it can lead to an enlargement of the left ventricle. This is why mitral valve insufficiency can cause enlargement of the left ventricle, primarily because it increases ineffective work, leading to an increased cardiac load.