What cardiac condition is characterized by rib notching on X-ray?

Rib notching on X-ray is a classic radiographic finding associated with coarctation of the aorta. This condition occurs when there is a narrowing of the aorta, usually distal to the left subclavian artery. The compromised blood flow leads to collateral circulation, primarily through the intercostal arteries. Over time, these collateral vessels erode the inferior surface of the ribs, resulting in notching that can be visualized on chest X-rays.

This finding helps in diagnosing coarctation of the aorta, particularly in pediatric populations or in younger adults who may present with hypertension in the upper body and lower blood pressure in the lower extremities. The presence of rib notching is not seen in the other conditions listed, as they have different pathophysiological characteristics and do not typically cause erosion of the ribs.

In patent ductus arteriosus, atrial septal defect, and ventricular septal defect, the pathophysiological changes do not lead to the bony alterations seen with coarctation of the aorta, making rib notching a distinct feature of the latter condition.