title: Authors' reply.
authors.affiliation: Department of Pediatric Cardiology, Wilhelmina Children's Hospital, University Medical Center Utrecht, Utrecht, The Netherlands.
authors.forename: Martijn G
authors.initials: MG
authors.lastname: Slieker
authors.affiliation: Department of Pediatric Cardiology, Wilhelmina Children's Hospital, University Medical Center Utrecht, Utrecht, The Netherlands.
authors.forename: Matthias W
authors.initials: MW
authors.lastname: Freund
mesh_terms: D000465:Algorithms; D001021:Aortic Valve / Q000000981:diagnostic imaging*; D004452:Echocardiography / Q000379:methods*; D005260:Female; D006801:Humans; D018636:Hypoplastic Left Heart Syndrome / Q000000981:diagnostic imaging*; D008297:Male; D008943:Mitral Valve / Q000000981:diagnostic imaging*