The role of echocardiography in the assessment of right ventricular systolic function in patients with transposition of the great arteries and atrial redirection

Background. - Although dysfunction of the systemic right ventricle (RV) in patients with complete transposition of the great arteries (TGA) after atrial redirection by Mustard or Senning procedures is well recognized, there are few data on systemic RV geometry and function. Echocardiography is a widely available imaging technique that is particularly suitable for clinical follow-up because of its non-invasive nature, low cost and lack of ionizing radiation. Aim. - To examine the feasibility and variability of transthoracic echocardiography variables in the assessment of the systemic RV. Methods. - Multivariable transthoracic echocardiographic analysis, including assessment of global function variables (RV ejection fraction [RVEF; Simpson's method], RV fractional shortening [RVFS] and dP/dt), longitudinal function variables (tricuspid annular plane systolic excursion [TAPSE], peak systolic velocity at the junction of the RV free wall and the tricuspid annulus, assessed with pulsed tissue Doppler imaging [S' TDI]), tricuspid regurgitation and asynchrony, was performed in 35 consecutive patients with TGA after atrial redirection. Functional variables were compared with magnetic resonance imaging (MRI). Inter- and intraobserver echocardiographic analysis variability was assessed in ten randomly selected cases. Results. - Global and longitudinal function variables were not correlated with RVEF calculated by MRI, except for S' TDI, which was weakly correlated (P = 0.02, r = 0.37). Asynchrony assessment was feasible in all patients. Inter- and intraobserver echocardiographic analysis variability was high for RVEF, RVFS and dP/dt (> 10%), and low for TAPSE and S' TDI (5%). Conclusion. - Owing to geometric changes, presumed contractility pattern shift and retrosternal position, conventional echocardiographic variables are not relevant for RV function assessment. Assessment of asynchrony and tricuspid regurgitation is easily feasible in routine practice and highly reproducible. Echocardiography does not permit complete assessment of the systemic RV after atrial redirection but is fully complementary with MRI and should not be abandoned. Future improvements in transducers and dedicated software should permit major improvements in the near future.