Occult atrial septal defect in adults.

Two patients are described who presented with congestive heart failure and were found to have an atrial septal defect with a pulmonary blood flow approximately twice the systemic blood flow. Most of the usual clinical signs of atrial septal defect were absent, and the diagnosis was established by right heart catheterization and radioisotopic angiography. Both patients had hypertension and coronary artery disease. Atrial septal defect in the adult patient may not be recognized because of associated cardiac disease, including coronary artery disease and hypertension, or pulmonary disease which may obscure the usual clinical signs of a septal defect. Radioisotopic angiography and right heart catheterization should be considered in any patients with heart disease or congestive failure of obscure cause even if the usual diagnostic signs of atrial septal defect are absent.