Multimodality imaging and functional assessment in patients with systemic right ventricle and biventricular physiology: the role of echocardiography.

Background: Systemic right ventricle (sRV) dysfunction is common in patients with ccTGA and D-TGA s/p Mustard/Senning, often leading to early mortality from heart failure. Therefore, a close follow-up of affected patients is crucial to identify early markers of cardiac dysfunction. Currently, standardized protocols for the assessment of sRV dysfunction are lacking. Purpose: The aim of the study is to compare standard and advanced echocardiographic parameters with CMR-derived parameters in patients with sRV and biventricular physiology and to evaluate their correlation with clinical variables and exercise capacity. Methods: Patients with cc-TGA and D-TGA after Mustard/Senning who underwent standard and advanced (speckle tracking and 3D) echocardiography and CMR (including feature-speckle tracking) between September 2022 and September 2023 were included. Clinical, imaging parameters and data derived from cardiopulmonary exercise testing (CPET) were collected. Results: 19 patients were included, median age at CMR was 28 years (IQR 17,25-33). Echocardiographic derived sRV areas correlated with 3D echocardiographic derived sRV volumes (r 0,6, p 0,006 for diastole; r 0,8, p 0,002 for systole). 3D ejection fraction (EF) correlated with FAC and TAPSE (r 0,8, p 0,001 and r 0,7, p 0,03). sRV GLS correlated with systemic atrial strain (sAS) (r -0.6, p 0.01). CMR-derived EF correlated with CMR-derived GLS both endocardial and myocardial (r -0.7, p 0.007; r -0,6, p 0,005). sRV areas as assessed by echo correlated with CMR-derived volumes (r 0.9, p 0.0001 for diastole, r 0.8, p 0.0001 for systole). Similarly, a correlation was found between sRV echo-derived GLS and CMR-derived GLS both endocardial and myocardial (r 0.8, p 0.001; r 0,7, p 0,01 respectively). The only imaging parameter that correlated with peak VO2 was sAS (r 0,55, p 0.04). When comparing cc-TGA and D-TGA s/p Mustard/Senning, the former showed better GLS-derived values as assessed by CMR (cRV-GLSendo -23.2% vs -17.2%, p 0.002; cRV-GLSmyo -21.2% vs -16.7%; p 0.05), bigger systemic atrial area (20.2 cm2/m2 vs 8.4 cm2/m2, p 0.005) and higher TAPSE values (16.2 mm vs 12.2 mm, p 0.04). Conclusions: Echocardiography is a valid tool to assess sRV dimension and function and to guide timing for CMR. The investigation of atrial deformation imaging may help to better understand diastolic function and the correlation between sAS and peak VO2 may suggest a major role of diastolic function in determining exercise capacity in patients with sRV. Our study also demonstrated that patients with cc-TGA exhibit better cardiac function compared to those with D-TGA after atrial switch.