Does delayed correction interfere with pulmonary functions and exercise tolerance in patients with tetralogy of fallot?

Study objectives: To assess exercise tolerance and determine the distinct role of cardiac, respiratory, or peripheral factors on it after delayed surgical repair in patients with tetralogy of Fallot. Design: The aerobic exercise capacity of 15 adult patients (mean [+/- SD] age, 21 +/- 6; age range, 9 to 30 years) undergoing successful total correction at a mean age of 12 +/- 5 years (patients) was compared to healthy, matched control subjects by using right ventricle echocardiography, resting spirometry, and cardiopulmonary exercise tests at a mean postoperative time of 7.5 +/- 4.6 years. Setting: Tertiary care referral centers. Patients: Fifteen adult patients (mean age, 21 +/- 6 years; age range, 9 to 30 years) undergoing successful total correction at a mean age of 12 +/- 5 (patients) and 15 healthy, matched volunteers (control subjects). Results: There was evidence for a slight right ventricular diastolic dysfunction in the patients. Mean FVC (88 +/- 9% vs 109 +/- 12% predicted, respectively) and FEV, (89 +/- 9% vs 109 +/- 12% predicted, respectively), although being within the normal range, were also decreased in comparison to those of control subjects (p < 0.0001). Maximal oxygen consumption (Vo(2)max) decreased in both groups (55 +/- 16% vs 61 +/- 23% predicted, respectively; p = 0.5); however, there were more individuals with severely decreased values among the patients (p = 0.05). Vo(2) at the anaerobic threshold was also decreased in patients (33 +/- 15% vs; 51 +/- 8% predicted, respectively; p = 0.004). The maximum tolerable exercise time was 17.3 +/- 4.5 min in patients vs 21.2 +/- 6.4 min in control subjects (p = 0.06). Conclusions: The exercise capacity after delayed repair was good in general compared to matched control subjects; however, exercise capacity may be slightly limited by ventilatory dysfunction, low anaerobic threshold, and lack of physical fitness despite New York Heart Association class improvement after undergoing the operation.