The study aim was to investigate ventricular function at long-term follow-up in patients operated with arterial switch for transposition of the great arteries (TGAs). Although midterm results for anatomic correction of TGA are promising, there are reported minor alterations in left ventricular (LV) function possibly indicating myocardial dysfunction. Twenty-two patients with TGAs 12.4 +/- 2.3 years old operated with arterial switch were studied by magnetic resonance imaging and echocardiography. Twenty-two age-matched healthy subjects served as controls. Myocardial deformation was described by longitudinal and circumferential shortening (measured as strain and strain rate) and ventricular torsion, measured by speckle-tracking echocardiography. Although standard measurements of global systolic LV function were normal in patients with TGAs, longitudinal shortening was decreased compared with controls. Longitudinal strain was decreased in all ventricular regions except the posterior wall and most pronounced in the apical segments. LV circumferential shortening was similar in the 2 groups. Also, in the right ventricular free wall patients displayed decreased longitudinal shortening in the mid and apical segment. Moreover, LV torsion was decreased in the TGA group. Although rotation was relatively homogenous at the apical and basal levels in controls, there was greater dispersion in rotation in the patient group, with basal rotation being greatest in the inferior wall and apical rotation being greatest in the anterior wall. In conclusion, there was slightly decreased longitudinal shortening in the 2 ventricles and decreased LV torsion in patients with TGAs, although standard measurements of global ventricular function were normal.