Magnetic Resonance Imaging Assessment of Right Ventricular Deformation in Patients With Transposition of the Great Arteries.

PURPOSE

To detect changes of right ventricular (RV) myocardial deformation in patients with systemic RV (SRV) and transposition of the great arteries (TGA) as compared with individuals without structural heart disease.

MATERIALS AND METHODS

We performed a retrospective analysis of cine steady-state free precession cardiac magnetic resonance imaging sequences acquired using a 1.5 T scanner in short-axis and long-axis views in 25 patients with SRV (16 with atrial switch repair for D-TGA and 9 with congenitally corrected TGA; age range 19 to 68, 13 males). The control group consisted of 25 individuals without structural heart disease (age range 10 to 73, 14 males). Besides routine RV magnetic resonance imaging volumetry, mean longitudinal RV strain was measured on a 4-chamber view, and mean circumferential RV strain on 3 short-axis images (basal, midventricular, and apical) based on feature tracking. The strain parameters were statistically compared between patients with SRV and the control group.

RESULTS

Patients with SRV, compared with the control group, had significantly higher RV-indexed end-diastolic volume (122±40 vs. 70±9 mL/m 2 , P <0.001), lower RV ejection fraction (45±12% vs. 62±6%, P <0.001), and reduced mean longitudinal RV strain (-13.7±3.6% vs. -21.6±2.7%, P <0.001). There was no relevant difference between mean circumferential SRV strain in the basal and midventricular plane; however, in patients with SRV, mean circumferential strain was reduced at the apical level (-12.0±6.1% vs. -17.9±5.6%, P <0.001).

CONCLUSIONS

SRV failure could be explained by reduced longitudinal SRV strain caused by the longitudinal orientation of RV myocardial fibers. In patients with SRV, circumferential RV strain is only reduced in apical segments.