Anomalous pulmonary venous connection is a congenital abnormality in which varying numbers of pulmonary veins (from one to all) attach to the right atrium or a systemic vein.

Endocardial cushion defects (atrioventricular [AV] canal defects, persistent AV ostium, AV septal defects) involve abnormalities of endocardial cushion development and can produce septum primum defects, AV valve abnormalities, and ventricular septal defects.

Cor triatriatum sinister and dexter result from a fibrous membrane dividing the left or right atrium, respectively. Cor triatriatum sinister has been reported in cats and cor triatriatum dexter in dogs. The affected atrium is divided into 2 chambers. There are commonly one or more perforations in the separating membrane, allowing communication between the 2 portions of the atrium. Successful balloon valvuloplasty for this disease has been reported.

Dextrocardia, positioning of the heart in the right hemithorax, can occur as a congenital cardiac defect and by itself is typically benign. It can also occur in combination with situs inversus (an abnormal orientation of the organs of the body). The combination of these defects is typically noted in animals with other concurrent abnormalities such as sinusitis, bronchitis, and bronchiectasis.

In addition to these defects, several others are reported, including double outlet right ventricle (all of one great artery and the majority of another great artery originate from the right ventricle), interruption of the aortic arch, persistent left cranial vena cava, pulmonary atresia, and transposition of the great arteries.

Last full review/revision April 2012 by Davin Borde, DVM, DACVIM