Cor pulmonale is failure of the right side of the heart, the side that pumps blood to the lungs. This problem occurs when the heart has to work harder to pump blood through damaged lungs, such as when a person's lungs are damaged because of chronic obstructive pulmonary disease (COPD).

People with cor pulmonale are short of breath because of their damaged lungs. They may have swollen legs and a swollen abdomen because of fluid retention (edema).