Declining aerobic capacity of patients with arterial and atrial switch procedures.

BACKGROUND: Patients with transposition of the great arteries corrected by an atrial switch procedure are believed to have a worse physical outcome than patients with an arterial switch procedure correction. This study aimed to compare exercise data for patients with the two surgical methods.
METHODS: This study retrospectively analyzed exercise treadmill test results for 7- to 17-year-old patients who underwent either an atrial switch procedure (n=45) or an arterial switch procedure (n=44). The results were compared with reference material.
RESULTS: Both groups showed significantly less aerobic capacity than healthy subjects. The atrial switch patients achieved 69% of reference status, and the arterial switch patients achieved 82%. A gradual decline in exercise capacity with increasing age was shown for patients with atrial switch circulation (p<0.0001). No significant difference was found for the arterial switch group (p=0.319).
CONCLUSIONS: Significantly less aerobic capacity was found in atrial and arterial switch patients than in healthy subjects. A decline in aerobic capacity with increasing age was found in the atrial switch patients. However, the small number of teenagers in the arterial switch group limits the ability to be conclusive. The results indicate that chronotropic incompetence may be one of the reasons for diminishing capacity. The decline in exercise performance leads the authors to recommend regular follow-up exercise testing.