Background: Quantitative echocardiographic assessment of right ventricular function is important in children with hypoplastic left heart syndrome (HLHS). The aim of this study was to examine the repeatability of different echocardiographic techniques, both manual and automated, to measure fractional area change (FAC) in patients with HLHS and to correlate these measurements with magnetic resonance imaging (MRI)-derived ejection fraction (EF). Methods: Fifty-one children with HLHS underwent transthoracic echocardiography and cardiac MRI under the same general anesthetic as part of routine inter-stage assessment. FAC was measured from the apical four-chamber view using three different techniques: velocity vector imaging (VVI) (Syngo USWP 3.0; Siemens Healthineers), QLAB (Q-lab R 10.0; Philips Healthcare), and manual endocardial contour tracing (Xcelera, Philips Healthcare). Intra- and inter-observer variability was calculated using intra-class correlation coefficient (ICC). FAC was correlated with MRI EF calculated using a single standard method. Results: Fractional area change had a good correlation with MRI-derived EF with an R value for VVI, QLAB, and manual methods of.7,.6, and.4, respectively. Intra- and inter-observer variability for FAC was good for automated echocardiographic methods (ICC>.85) but worse for manual method particularly inter-observer variability of FAC and end-systolic area. Both automated techniques tended to produce higher FAC values compared with manual measurements (P<.001). Conclusion: Automation improves the repeatability of FAC in HLHS. There are some differences between automated software in terms of correlation with MRI-derived EF. Measurement bias and wide limits of agreement mean that the same echocardiographic technique should be used during the follow-up of individual patients.
Bibliographical noteFunding Information:
The authors extend warm thanks to statistical advisor Tuomas Selander, MSc, from Kuopio University Hospital. This study was supported by grants from the Kirsti and Tor Johansson Foundation, Helsinki, Finland; Finnish Cultural Foundation, North-Savo Regional Fund, Kuopio, Finland; Foundation for Pediatric Research, Helsinki, Finland; and Finnish Foundation for Cardiovascular Research, Helsinki, Finland. Additionally, the authors would like to thank the staff of the MRI and pediatric cardiology department at Evelina Children's Hospital. This study has received funding by the Department of Health through the National Institute for Health Research (NIHR) Comprehensive Biomedical Research Centre award to Guy's & St Thomas' NHS Foundation Trust in partnership with King's College London and King's College Hospital NHS Foundation Trust. The Division of Imaging Sciences receives also support as the Centre of Excellence in Medical Engineering (funded by the Wellcome Trust and EPSRC; grant number WT 088641/Z/09/Z) as well as the BHF Centre of Excellence (British Heart Foundation award RE/08/03). HBR acknowledges funding from the EuHeart Virtual Physiological Human Network of Excellence (European Union FP7/2007-2013) under grant agreement no. 224495.
© 2017, Wiley Periodicals, Inc.
- fractional area change
- hypoplastic left heart syndrome
- myocardial function
- velocity vector imaging