Quantification of Right Ventricular Volume and Function Using Single-Beat Three-Dimensional Echocardiography: A Validation Study with Cardiac Magnetic Resonance

Background: Because of the unique geometry of the right ventricle, assessment of right ventricular (RV) volume and function is clinically challenging. The aim of this study was to investigate the feasibility of single-beat three-dimensional echocardiography (sb3DE) for RV volume and functional assessment in patients with dilated right ventricles. Methods: Fifty-two patients with severe tricuspid regurgitation or atrial septal defects were enrolled. Fifty patients underwent sb3DE and cardiac magnetic resonance (CMR) within 24 hours under a euvolemic state, and the results of sb3DE were compared with those of CMR, the reference method. Fifteen normal subjects were also recruited for a broader validation of sb3DE. Results: Of the 67 individuals, data from 59 study participants (44 patients and 15 normal subjects) with adequate image quality were analyzed (mean age, 46.9 +/- 19.3 years; 58% women). The correlation was excellent between sb3DE and CMR for measuring RV volumes and RV ejection fraction (RVEF) (r = 0.96, r = 0.93, and r = 0.93 [P < .001 for all] for RV end-diastolic volume, RV end-systolic volume, and RVEF, respectively). Bland-Altman analysis revealed that RV volumes, but not RVEF, tended to be slightly underestimated by sb3DE (-5.8 +/- 9.6%, -3.8 +/- 14.1%, and -1.2 +/- 9.4% for RV end-diastolic volume, RV end-systolic volume, and RVEF, respectively). Intra-and interobserver variability was acceptable for all indices (4.9% and 6.1% for RV end-diastolic volume, 4.2% and 7.9% for RV end-systolic volume, and 5.7% and 2.8% for RVEF, respectively). Among patients with RV dilation, the difference in RVEF between sb3DE and CMR was more pronounced in patients with atrial fibrillation than those in sinus rhythm (-5.9% vs 0.9%, P = .041). Conclusions: In patients with dilated right ventricles and in normal subjects, assessment of RV volume and systolic function by sb3DE is feasible in terms of accuracy and reproducibility. RV analysis using sb3DE can be performed in patients with atrial fibrillation, with the possibility of RVEF underestimation.