eu8bkr - The right ventricle (RV) is the lower part or chamber of the right side of the heart. It pumps all its blood to the pulmonary arteries and lungs where it gets rid of excess carbon dioxide (CO2) and picks up needed oxygen before returning to the left side of the heart and then to the rest of the body. Enlargement of the right ventricle occurs either when there is a blockage or narrowing of the pulmonary arteries or increased resistance to blood flow in the lungs which increases the back pressure on the RV to pump harder making the RV enlarge. Other causes include some congenital abnormalities and some heart valve defects. Treatment depends upon an exact diagnosis.