Cor Pulmonale (right-sided heart enlargement and failure): This condition is characterized by the enlargement of the heart's right ventricle. The right ventricle is forced to exert more effort than usual to pump blood through narrowed or obstructed pulmonary arteries. Initially, the heart muscle walls thicken (hypertrophy) and the right ventricle dilates to accommodate a larger blood volume; this is an attempt to counteract the increased pulmonary resistance. However, these prolonged compensatory mechanisms place an additional burden on the heart, ultimately leading to right ventricular failure.