title: Effects of L-thyroxine treatment on heart functions in infants with congenital hypothyroidism.
abstract: BACKGROUND
  Impaired heart functions in newborns with hypothyroidism should be reversed by levothyroxine substitution therapy. The aim of the study was to investigate heart functions with congenital hypothroidism (CH) in newborns and changes after levothyroxine substitution therapy, measured with tissue Doppler echocardiography and conventional echocardiography.
  
  
  METHODS
  The study included 30 neonates with CH and 34 healthy controls. Echocardiography were performed at baseline, 2nd week and 6th month of therapy.
  
  
  RESULTS
  Heart systolic function was normal. Mitral E velocities and mitral E/A ratios were significantly lower in patients at baseline. Tei indices were significantly higher in patients and a significant negative correlation was detected between free thyroxine levels and Tei indices.When early and late post-treatment echocardiography findings are compared, a non-significant difference was detected.
  
  
  CONCLUSIONS
  Neonates with CH may exhibit systolic and diastolic heart dysfunction, which can be reversed by early L-T4 substitution treatment. The Tei index index should be measured in addition to conventional echocardiography.
authors.affiliation: Division of Pediatric Cardiology Başkent University Faculty of Medicine, Adana Dr. Turgut Noyan Medical and Research Center, Adana.
authors.forename: Alev
authors.initials: A
authors.lastname: Arslan
authors.affiliation: Divison of Pediatric Endocrinology, Department of Pediatrics, Kayseri Education and Research Hospital, Kayseri.
authors.forename: Veysel Nijat
authors.initials: VN
authors.lastname: Baş
authors.affiliation: Department of Pediatrics, Kayseri Education and Research Hospital, Kayseri.
authors.forename: Salih
authors.initials: S
authors.lastname: Uytun
authors.affiliation: Department of Pediatrics, Kayseri Education and Research Hospital, Kayseri.
authors.forename: Hatice Gamze
authors.initials: HG
authors.lastname: Poyrazoğlu
mesh_terms: D016022:Case-Control Studies; D003409:Congenital Hypothyroidism / Q000188:drug therapy* / Q000473:pathology; D004452:Echocardiography; D005260:Female; D006801:Humans; D007223:Infant; D007231:Infant, Newborn; D008297:Male; D013974:Thyroxine / Q000627:therapeutic use*; D016277:Ventricular Function, Left / Q000187:drug effects / Q000502:physiology*; D016278:Ventricular Function, Right / Q000187:drug effects / Q000502:physiology*
chemical_list: D013974:Thyroxine
keywords: Tei index; congenitally hypothyroidism; heart failure; tissue Doppler echocardiography