Aims: Different echocardiographic techniques are available for assessing right ventricular (RV) volumes but their clinical validity has not been well established. We compared the feasibility, reproducibility and accuracy of three different echocardiographic techniques for measuring RV volumes and ejection fraction (EF) in children after tetralogy of Fallot (TOF) repair.
Methods and results: Seventy patients (age 14.2 ± 7.3 years) were studied using three-dimensional (3D) volume acquisition analysis (Tomtec, Germany), 2D echo with knowledge-based 3D reconstruction (3DR) (Ventripoint, USA) and the four-chamber area (4C area) methods. Parameters analysed were RV end-diastolic volume (EDV), end-systolic volume and EF. Magnetic resonance imaging (MRI) data were available in 41 patients. Intra- and inter-observer as well as inter-technique variability was assessed using Pearson's correlation analysis (R), coefficient of variance, and Bland-Altman analysis. Feasibility was good for all echo techniques (91% for the 3D, 98% for the 3DR, and 100% for the 4C area method). Intra- and inter-observer variability was low for both 3DR and the 3D echo, while more variability was observed for the 4C method. Compared with MRI volumes, 3DR and 3D underestimated EDV by 6.6 ± 10 and 18.2 ± 17.8 mL, respectively, (P < 0.001), while the 4C area method overestimated the EDV by 9.6 ± 33 mL, not significant due to a wide range.
Conclusion: Current echocardiographic techniques to assess RV volumes are highly feasible and reproducible in paediatric post-operative TOF patients. When compared with MRI measurements, 3DR was the most accurate technique but requires extra equipment that is not readily available.