Intraatrial repair of transposition of the great arteries: use of MR imaging after exercise to evaluate regional systemic right ventricular function.

PURPOSE

To prospectively assess regional systemic right ventricular (RV) function at rest and in response to exercise by using magnetic resonance (MR) imaging in patients who have undergone surgical correction at the atrial level for transposition of the great arteries (TGA).

MATERIALS AND METHODS

Informed consent was obtained, and the medical review board approved this study. In 25 adult patients (mean age, 25.8 years +/- 4.7 [standard deviation]; 13 men) who had undergone correction for TGA (23.4 years +/- 4.9 after surgery) and 11 healthy volunteers (mean age, 27.4 years +/- 2.7; six men), systemic ventricular function was assessed with MR imaging (turbo field echo-planar imaging) at rest and during supine bicycle exercise. Regional wall thickness and wall thickening of the systemic RV were assessed and compared with those of the left ventricle in healthy volunteers by two investigators working together. Regional wall parameters were calculated by using the three-dimensional centerline method. Independent-samples t test and paired-samples t test were used for statistical analysis.

RESULTS

Ejection fraction of the systemic RV did not increase after exercise (56% +/- 8 at rest to 55% +/- 7 after exercise, P = .196). Mean RV wall thickening was impaired in patients with TGA at all levels both at rest and in response to exercise (P < .05). Moreover, the free wall and the anterior wall of the systemic RV had a smaller end-systolic thickness and a diminished thickening at rest and after exercise compared with findings in the normal left ventricle (P < .05).

CONCLUSION

The systemic RV of patients after intraatrial correction for TGA reveals regional functional disturbances at rest and in response to exercise.