Definition of Patent Ductus Arteriosus
The ductus arteriosus is a normal fetal blood vessel connecting the aorta and the pulmonary artery. This allows the blood of unborn puppies to bypass their non-functioning lungs; they get oxygen from their mother. The ductus arteriosus should close shortly before or just after birth, once a puppy takes its first breaths and its lungs inflate. In puppies with a patent ductus arteriosus (“PDA”), this channel stays open. PDAs are considered genetic, although they may be influenced by environmental, infectious, nutritional, pharmaceutical and toxicological factors. PDAs make the heart work too hard. The left heart chambers stretch, reducing blood flow from the heart. Affected dogs tire easily, become weak and lethargic, cough, have trouble breathing and have stunted growth. Many develop seizures and fainting episodes. Left untreated, PDAs will contribute to congestive heart failure and are almost always fatal. They are among the most common congenital heart defects in dogs.