# Utility of three-dimensional echocardiography for evaluating right ventricular size and function and ventricular myocardial deformation in repaired tetralogy of fallot

## TL;DR

Three-dimensional echocardiography is a promising alternative to MRI for assessing heart function in repaired Tetralogy of Fallot patients.

## Contribution

3DE shows strong correlation with CMR for RV volumes and provides clinically relevant strain measurements in rTOF patients.

## Key findings

- 3DE strongly correlates with CMR for RVEDV and RVEDVi but slightly underestimates values.
- 3DE-derived RV-GLS is more negative than 2DE and detects systolic dysfunction in CMR-defined cases.
- 3DE may serve as a complementary tool for longitudinal RV assessment in rTOF patients.

## Abstract

Right ventricular (RV) dysfunction remains a major long-term complication in patients with repaired Tetralogy of Fallot (rTOF). While cardiac magnetic resonance (CMR) is the gold standard for right ventricular (RV) assessment, it is limited by accessibility and cost. Three-dimensional echocardiography (3DE), with its strain imaging capabilities, offers a promising alternative for the serial evaluation of right ventricular (RV) size and function. This study aims to compare RV volumetric and myocardial deformation parameters obtained by 2D and 3D echocardiography (2DE, 3DE) with RV function measured by CMR in patients with rTOF.

We retrospectively analyzed 43 patients with rTOF who underwent same day 2D, 3D echocardiography, and CMR between November 2023 and December 2024. RV volumes, ejection fraction (RVEF), and global longitudinal strain (GLS) were measured across modalities. Correlation, Bland-Altman analysis, and area under receiver operating characteristic (AUC) curves were used to evaluate the agreement and diagnostic accuracy for detecting right ventricular (RV) systolic dysfunction.

Three-DE demonstrated a strong correlation with CMR for RVEDV (r = 0.95) and RVEDVi (r = 0.91), with a mild underestimation. RVEF by 3DE was significantly lower than CMR (46.4 ± 8.8% vs. 50.3 ± 7.3%, p = 0.002). RV-GLS values differed across modalities, with 3DE yielding more negative values than 2DE (−20.3 ± 4.4% vs. −18.5 ± 4.7%, p = 0.009). Among patients with CMR-RVEF <48%, both 2D and 3D Echo-derived RV-GLS were significantly reduced.

Three-dimensional echocardiography demonstrates a consistent association with CMR for the assessment of right ventricular volumes but modest underestimation of volumetric and functional parameters. Abnormal right ventricular strain was observed in patients with CMR-defined systolic dysfunction, supporting the clinical relevance of strain analysis. Overall, 3DE may serve as a feasible complementary tool for longitudinal right ventricular assessment in patients with rTOF, alongside CMR as the reference standard.