Simultaneous Volumetric and Functional Right Ventricular Assessment by Principal Strain Analysis in Children with Repaired Tetralogy of Fallot

Aims: Principal strain (PS) analysis using 3D speckle-tracking echocardiography enables us to simultaneously measure 3D ventricular volumes and strains. PS quantifies 3D deformation by defining not only amplitude but also direction of principal myocardial contraction (PS angle). This study aims (i) to validate volumetric and functional parameters using PS analysis in volume-overloaded right ventricle (RV) of repaired tetralogy of Fallot (rTOF) vs. cardiac magnetic resonance (CMR) and (ii) to describe PS analysis indices in patients undergoing pulmonary valve replacement (PVR). Methods and results: Sixty-four paediatric patients with rTOF (12.4 ± 5.2 years) and 58 age-matched healthy children (12.8 ± 3.7 years) were prospectively included. We calculated PS magnitude [global PS (GPS)] and angle, indexed RV end-diastolic and end-systolic volumes (EDVi and ESVi), RV ejection fraction (EF), and conventional strains. Among rTOF patients, 32 CMRs were available. First, we validated volumetric parameters obtained by PS analysis against CMR. Second, we compared these indices between rTOF patients and controls. Lastly, we evaluated the discriminative value of PS analysis in PVR. PS analysis and CMR measurements showed good correlations (EDVi, r = 0.80; ESVi, r = 0.74; and EF, r = 0.70, P < 0.001). GPS showed the highest correlation with 3D-EF (r = -0.84, P < 0.001). rTOF patients exhibited nearly doubled RV volume and significantly decreased 3D-EF and conventional strains. PS magnitude also decreased in rTOF patients, with altered PS angles in RV free wall. Volume measurements of RV showed the highest predictive value for discriminating PVR (+) by receiver operating characteristic analysis, followed by PS functional parameters. Conclusion: PS analysis is a reliable and reproducible method for both volumetric and functional analysis of volume-overloaded RV in rTOF, which can be of incremental value for defining the indications for PVR.