Incidental discovery of a patent ductus arteriosus in adults.

Patent ductus arteriosus (PDA) is an uncommon clinical finding in adult primary care patients. However, with improved survival of premature infants at risk for PDA and an increase in cases discovered incidentally on echocardiograms performed for other purposes, the incidence of PDA is rising. Thus, primary care physicians need to be alert to the clinical situations suggesting a previously undiagnosed PDA. It is estimated that the incidence of PDA is approximately 0.02% to 0.04% in term infants and slightly higher in premature infants. PDA accounts for 6% to 11% of all congenital heart defects. Although most cases of PDA would seem to occur sporadically, multifactorial inheritance is believed to underlie many cases. These people are thought to possess a genetic predisposition acted on by an environmental trigger that occurs at an unknown but vulnerable time during the pregnancy. The clinical spectrum of presentation of a PDA may range from a "silent" PDA, one with no clinical manifestations but which is incidentally discovered on echocardiogram for other purposes, to patients who present with congestive heart failure, pulmonary hypertension, signs of volume overload, endocarditis, atrial fibrillation, or "recurrent pneumonia." We describe 2 cases that illustrate the discovery of an asymptomatic PDA during routine physical examination of adult patients.