Long-term myocardial performance of the systemic right ventricle during exercise in patients with transposition of the great arteries and atrial switch operation.

Objective: The echocardiographic assessment of the systemic right ventricle (sRV) performance during stress testing is limited and evaluation is not routinely performed. The aim of the study is to investigate sRV myocardial performance at rest and with exercise in patients with complete transposition of the great arteries (dTGA) who have undergone atrial switch operation.

Methods: In a single-center cross-sectional study, 41 patients with dTGA following the atrial switch operation and gender-matched 20 healthy volunteers underwent exercise echocardiography on a bicycle ergometer in the semi-supine position to assess sRV systolic function indices: tricuspid annular plane systolic excursion (TAPSE), right ventricular area change (FAC), global longitudinal strain (GLS) and systemic velocity time integral (VTI).

Results: Patients with sRV were characterized by lower systolic function assessed by TAPSE, s', FAC, GLS both at baseline and at peak exercise, compared with the control group. sRV GLS decreased during exercise in patients with sRV (-6 + 2.84) compared to increased in patients with systemic left ventricle (0.47 + 2.74), p < 0.001. There was no increase in VTI during exercise in patients with sRV, compared to controls (Δ VTI -0.01 ± 2.96 cm vs. Δ VTI 4.50 ± 3.13 cm, p < 0.001). There was a trend towards higher chronotropic incompetence in patients with sRV vs. control (61% vs. 45%, p = 0.28).

Conclusion: Our results confirmed that patients with dTGA have reduced ability to increase myocardial contractility and stroke volume during exercise. Chronotropic incompetence was prevalent in dTGA patients.