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 FEV1 (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 (V(O2max) 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). V(O2) 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.