[Comparison of exercise capacity evaluated by cardiopulmonary exercise test and hemodynamic parameters in patients with atrial septal defect].

We evaluated the maximal exercise tolerance using cardiopulmonary exercise testing, and investigated the relation of the hemodynamic parameters such as mean pulmonary artery pressure (PAm) and pulmonic-to-systemic flow ratio (Qp/Qs) to exercise tolerance in 18 adult patients consecutively. All the patients had atrial septal defect (ASD). Maximal oxygen uptake (VO2 max) averaged only 21.6 +/- 5.6 ml/min/kg and 63.5 +/- 16.2% of the predicted values (VO2max). And anaerobic threshold averaged 12.5 +/- 2.3 ml/min/kg and 56.7 +/- 12.4% of the predicted values. There were 2 patients who had marked pulmonary hypertension (PH, PAm more than 44 mmHg). Maximal exercise tolerance of these patients was severely impaired, and %VO2max was only 45.9% and 46.2% respectively. In patients without PH (PAm less than 20 mmHg), however %VO2 max ranged widely from 100.3 to 44.7% and PAm correlated with %VO2max weakly (r = -0.53, p less than 0.05). But there was a significant inverse relationship between Qp/Qs and %VO2max(r = -0.85, p less than 0.01). In 16 patients without PH, maximal O2-pulse during exercise was also inversely correlated with Qp/Qs (r = -0.76, p less than 0.01). The relation between PAm and %VO2max suggests that afterload on the right ventricle may be an important determinant of exercise capacity in patients with PH. And the relation between Qp/Qs and %VO2max or Qp/Qs and % maximal O2-pulse suggests that Qp/Qs may also be a very important determinant factor of exercise capacity in patients without PH.