title: Abnormal cardiac contractility in long-term exogenous subclinical hyperthyroid patients as demonstrated by two-dimensional echocardiography speckle tracking imaging.
abstract: BACKGROUND
  Subclinical hyperthyroidism is associated with cardiovascular morbidity. Recent advances in echocardiography imaging have allowed sophisticated evaluation of myocardial tissue properties.
  
  
  OBJECTIVE
  To investigate the myocardial effects of long-term exogenous subclinical hyperthyroidism using two-dimensional speckle tracking echocardiography imaging (2D-STE).
  
  
  METHODS
  Prospective, single-blinded, placebo-controlled randomized trial of 6 months duration with two parallel groups.
  
  
  METHODS
  Totally 25 patients with a history of differentiated thyroid carcinoma on long-term TSH-suppressive levothyroxine (l-T(4)) substitution were randomized to persistent TSH-suppressive l-T(4) substitution (low-TSH group) or restoration of euthyroidism. Additionally 40 euthyroid controls were studied. RESULTS (PROPOSAL): At baseline, the group of patients showed normal left ventricular (LV) systolic function but impaired diastolic function as assessed with conventional echocardiographic parameters. Importantly, 2D-STE analysis demonstrated the presence of subclinical LV systolic and diastolic dysfunction with impaired circumferential and longitudinal strain and strain rate at the isovolumic relaxation time. After restoration of euthyroidism, a significant improvement in LV systolic and diastolic function as assessed with 2D-STE strain was observed.
  
  
  CONCLUSIONS
  Prolonged subclinical hyperthyroidism leads to systolic and diastolic dysfunction, which is reversible after restoration of euthyroidism. 2D-STE is a more sensitive technique to evaluate subtle changes in LV performance of these patients.
authors.affiliation: Department of Endocrinology and Metabolism, C4-R, Leiden University Medical Center, PO Box 9600, 2300 RC Leiden, The Netherlands.
authors.forename: Randa M
authors.initials: RM
authors.lastname: Abdulrahman
authors.forename: Victoria
authors.initials: V
authors.lastname: Delgado
authors.forename: Arnold C T
authors.initials: AC
authors.lastname: Ng
authors.forename: See Hooi
authors.initials: SH
authors.lastname: Ewe
authors.forename: Matteo
authors.initials: M
authors.lastname: Bertini
authors.forename: Eduard R
authors.initials: ER
authors.lastname: Holman
authors.forename: Guido C
authors.initials: GC
authors.lastname: Hovens
authors.forename: Alberto M
authors.initials: AM
authors.lastname: Pereira
authors.forename: Johannes A
authors.initials: JA
authors.lastname: Romijn
authors.forename: Jeroen J
authors.initials: JJ
authors.lastname: Bax
authors.forename: Johannes W
authors.initials: JW
authors.lastname: Smit
mesh_terms: D000328:Adult; D001794:Blood Pressure; D015331:Cohort Studies; D004452:Echocardiography / Q000379:methods; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D006980:Hyperthyroidism / Q000150:complications / Q000000981:diagnostic imaging* / Q000503:physiopathology*; D008297:Male; D008875:Middle Aged; D009200:Myocardial Contraction / Q000502:physiology*; D011446:Prospective Studies; D016037:Single-Blind Method; D013997:Time Factors; D018487:Ventricular Dysfunction, Left / Q000000981:diagnostic imaging* / Q000209:etiology / Q000503:physiopathology*