Although right ventricular (RV) dysfunction is an important complication in
subjects with congenitally corrected transposition of the great arteries,
its pathogenesis is poorly understood. We assessed the role of RV myocardia
l perfusion and found perfusion defects at rest in all 20 patients, involvi
ng 4.6 +/- 2.3 of a total of 12 segments; the extent of the resting perfusi
on defects correlated inversely with the RV ejection fraction.