Pectus excavatum is a common congenital malformation of the sternum and costochondral cartilages affecting cats, especially males.
The condition results in a ventral dorsal narrowing of the chest or a depression of the sternum into the chest cavity. This deformity reduces effective pulmonary function and may also interfere with cardiac function.
Signs often include exercise intolerance, weight loss, dyspnoea, pneumonia, cyanosis, coughing and postural deficits. A heart murmur may be auscultated and echocardiography is recommended to exclude the possibility of a concurrent primary heart disease. This is especially true in older cats that develop clinical signs as adults. It has been associated with other congenital defects e.g. pericardio-diaphragmatic hernia.
Some cats may have no obvious associated clinical signs and will lead normal lives. Those with moderate to severe deformity should be treated surgically with placement of an external fiberglass splint contoured to normal thoracic shape.
One possible adverse side effect of external splint correction is re-expansion pulmonary oedema. Older patients who have less thoracic compliance may benefit from a partial sternectomy.