Some physiologic features of atrial septal defect: Observations in 38 adult patients

1. (1) Thirty-eight adult patients with atrial septal defect have been studied before operation, and 20 have been restudied postoperatively. 2. (2) Of the group, two had significant mitral valve disease and two were of the ostium primum type although they could not be separated from the secundum defects by their hemodynamic findings. 3. (3) The major physiologic findings before operation were: (a) marked increase in pulmonary blood flow; (b) normal systemic blood flow; (c) mild elevation of pulmonary artery pressure; (d) lower than normal total pulmonary vascular resistance; (e) increased right ventricular pressure work; (f) normal systemic arterial blood oxygen saturation. 4. (4) Surgical correction of the atrial septal defect resulted in a reversion of the physiologic abnormalities towards or to normal. 5. (5) “Relative” pulmonary stenosis may be present in the face of marked increases in the pulmonary blood flow. 6. (6) The genesis of pulmonary hypertension in certain cases is not totally understood but may be related to: (a) pulmonary arteriolar sclerosis; (b) residual fetal pulmonary hypertension; (c) associated mitral valve disease; (d) “spasm” of the pulmonary arterioles.