An 8-week-old female, intact Cavalier King Charles Spaniel was evaluated for her grade V/VI basilar continuous murmur. The patient was otherwise clinically normal. Echocardiography confirmed a diagnosis of a patent ductus arteriosus (PDA), one of the most common congenital cardiovascular malformations in the dog. The unique pathophysiology of PDA lends itself to a discussion on the various treatment options available. Medical therapy is not curative and usually aimed at treating or preventing secondary disease states. Surgical closure of PDAs can be curative and has a good prognosis, extending the mean survival time in patients. Unless contraindicated, animals with PDAs are recommended to have their ductus closed.