Pulmonary atresia with ventricular septal defect: preoperative and postoperative responses to exercise.

Between April 1982 and June 1984, maximal exercise testing was performed 35 times in 34 consecutive patients with pulmonary atresia and ventricular septal defect (14 studies in patients without repair, 11 studies in patients with partial repair [insertion of a right ventricle to pulmonary artery conduit without ventricular septal defect closure] and 10 studies in patients with complete repair [insertion of a conduit with septal defect closure]). Total work performed, maximal power achieved, exercise time and maximal oxygen uptake were significantly greater in patients after partial or complete repair than in patients without repair. Systemic arterial blood oxygen saturations at rest and during exercise were directly related to the degree of repair. Although heart rate at rest in the three study groups was similar to that in a separate group of normal control subjects, patients in all three study groups had a blunted heart rate response to exercise. The ventilatory equivalent for oxygen was increased both at rest and during exercise for patients without conduit repair and those with a right ventricle to pulmonary artery conduit without ventricular septal defect closure but was similar to that of control subjects in the group with conduit insertion and septal defect closure. This study indicates that patients with pulmonary atresia and ventricular septal defect have decreased exercise tolerance both before and after corrective surgery. Exercise tolerance improves significantly after placement of a conduit from the right ventricle to the pulmonary artery with or without ventricular septal defect closure. Although no further improvement in exercise tolerance occurs with closure of the septal defect, ventilatory function and systemic arterial blood oxygen saturation are improved.