title: The effect of L-thyroxine treatment on left ventricular functions in children with subclinical hypothyroidism.
abstract: OBJECTIVE
  The aim of this study was to search for evidence suggesting treatment for childhood subclinical hypothyroidism (SH) by evaluating left ventricular (LV) functions of children with SH by using M-mode and tissue Doppler echocardiography (TDE).
  
  
  METHODS
  Children with SH and euthyroid healthy children (control group) were enrolled in the study. At baseline and 6 months after euthyroidism was achieved, M-mode and TDE were performed and LV functions were evaluated. Pretreatment parameters of the SH group were compared with those of controls and post-treatment parameters.
  
  
  RESULTS
  31 children with SH and 32 euthyroid healthy children were enrolled in the study. The groups had similar age, gender, puberty and body mass index. Interventricular septum thickness and LV mass index, which are the parameters for LV morphology, were slightly increased in the SH group than in the controls (p<0.05). In TDE, children with SH had significant changes in LV diastolic (lower E'm, higher E/E'm ratio and longer isovolumic relaxation time) and systolic functions (lower isovolumic contraction time) compared with controls (p<0.05). Six months after euthyroidism was achieved, TDE showed a significant improvement of some of the diastolic and systolic parameters (p<0.05).
  
  
  CONCLUSIONS
  The results of this study showed that SH is associated with subclinical alterations in LV function, and LT4 replacement may improve LV systolic and diastolic parameters. However, since SH is usually a self-limiting process, these improvements in LV functions may simply be associated with the natural course of the disease and/or physiological linear growth of the children.
authors.affiliation: Department of Pediatric Endocrinology, Faculty of Medicine, Dokuz Eylül University, Balcova, Turkey.
authors.forename: Gönül
authors.initials: G
authors.lastname: Çatli
authors.affiliation: Department of Pediatric Cardiology, Faculty of Medicine, Dokuz Eylül University, Balcova, Turkey.
authors.forename: Mustafa
authors.initials: M
authors.lastname: Kir
authors.affiliation: Department of Pediatric Endocrinology, Faculty of Medicine, Dokuz Eylül University, Balcova, Turkey.
authors.forename: Ahmet
authors.initials: A
authors.lastname: Anik
authors.affiliation: Department of Pediatric Cardiology, Faculty of Medicine, Dokuz Eylül University, Balcova, Turkey.
authors.forename: Nuh
authors.initials: N
authors.lastname: Yilmaz
authors.affiliation: Department of Pediatric Endocrinology, Faculty of Medicine, Dokuz Eylül University, Balcova, Turkey.
authors.forename: Ece
authors.initials: E
authors.lastname: Böber
authors.affiliation: Department of Pediatric Endocrinology, Faculty of Medicine, Dokuz Eylül University, Balcova, Turkey.
authors.forename: Ayhan
authors.initials: A
authors.lastname: Abaci
mesh_terms: D002648:Child; D002675:Child, Preschool; D015150:Echocardiography, Doppler; D005260:Female; D006801:Humans; D007037:Hypothyroidism / Q000188:drug therapy* / Q000503:physiopathology; D008297:Male; D013974:Thyroxine / Q000627:therapeutic use*; D018487:Ventricular Dysfunction, Left / Q000000981:diagnostic imaging / Q000503:physiopathology*; D016277:Ventricular Function, Left / Q000502:physiology*
chemical_list: D013974:Thyroxine
keywords: Cardiac function; Children; Endocrinology; Subclinical hypothyroidism; tissue Doppler echocardiography