Hemodynamic findings before and after surgery for atrial septal defect of the secundum type in middle-aged patients.

84 patients without concomitant pulmonary or cardiac disease, underwent surgery for atrial septal defect of the secundum type (ASD II) at the age of 40 years or more. Hemodynamics were studied preoperatively at rest, and postoperatively at rest and during exercise during a follow-up investigation which took place 74 months (range 22-174) after surgery. Preoperatively, the pulmonary artery mean pressure (PAMP) exceeded 20 mm Hg in 24 patients (30%). In the patients aged 50 years or more PAMP was significantly higher than in the younger patients, whereas the shunt ratio did not show any increase with age. After surgery, the pressures in right atrium, right ventricle and PA showed significant changes towards normalization. During exercise, a considerable increase of the PA pressures appeared, and this increase correlated significantly with the PA pressures obtained preoperatively at rest.