Real time three-dimensional echocardiographic quantification of left atrial volume in orthotopic heart transplant recipients: Comparisons with cardiac magnetic resonance imaging.

Abstract

The accuracy of real time three-dimensional echocardiography (RT-3DE) in evaluating left atrial volume (LAV) of heart transplant recipients against cardiac magnetic resonance (CMR) has not been reported. The aim of this study was to compare LAV with RT-3DE with respect to CMR in heart transplant recipients. Thirty-one heart transplant recipients who received echocardiogram and CMR examination on the same day were prospectively enrolled. The maximal LAV, minimal LAV by RT-3DE, and two-dimensional echocardiography (2DE) were compared with CMR measurements. Inter-technique comparisons included Pearson's correlation coefficient and Bland-Altman analysis. Reproducibility of 2DE and RT-3DE technique was assessed by intra-class correlation coefficient (ICC). RT-3DE-derived LAV values showed higher correlation with CMR than 2DE measurements in heart transplant recipients (r=.93 vs r=.76 for maximal LAV; r=.91 vs r=.81 for minimal LAV). Two-dimensional echocardiography underestimated maximal LAV by 10±31mL and minimal LAV by 26±26mL. Although RT-3DE underestimated minimal LAV 15±19mL, no significant difference between RT-3DE and CMR was observed in maximal LAV (RT-3DE: 86±22mL; CMR: 89±23mL, P=.079), with a negligible bias of 3mL. Inter-observer and intra-observer agreement were excellent for 2DE and RT-3DE parameters. Compared with CMR reference, RT-3DE-derived LAV measurements are more accurate than 2DE-based analysis in heart transplant recipients, especially with regard to the assessment of maximal LAV. RT-3DE may be a valid alternative to CMR for quantification LAV in heart transplant recipients.