title: Effect of central hypothyroidism on Doppler-derived myocardial performance index.
abstract: BACKGROUND
  Myocardial performance index (MPI) has been used to assess global ventricular function in different types of cardiac disease. Thyroid hormones influence cardiac performance directly and indirectly by changes in peripheral circulation. The aim of this study was to evaluate the possible effect of central hypothyroidism (CH) on MPI.
  
  
  METHODS
  The study included 28 control subjects and 7 patients with CH without cardiac disease. MPI was defined as the sum of isovolumetric contraction time (ICT) and isovolumetric relaxation time divided by ejection time. Patients were submitted to hormonal therapy with thyroxin and the study was repeated after 35 to 42 days.
  
  
  RESULTS
  MPI was significantly higher in patients with CH (0.54 +/- 0.08) than in control subjects (0.40 +/- 0.05) (P =.002). The increase in MPI was caused by the prolongation of ICT without a significant variation of isovolumetric relaxation time and ejection time. After hormonal therapy there was a significant reduction of MPI (0.54 +/- 0.08 vs 0.42 +/- 0.07; P =.028) and ICT.
  
  
  CONCLUSIONS
  MPI was increased in patients with untreated CH. The increase was related to prolongation of ICT and reverted by hormonal therapy.
authors.affiliation: Division of Cardiology, Paulista School of Medicine, Federal University of Sao Paulo, Brazil. fabiodoin@terra.com.br
authors.forename: Fabio Luiz Casanova
authors.initials: FL
authors.lastname: Doin
authors.forename: Mariana da Rosa
authors.initials: Mda R
authors.lastname: Borges
authors.forename: Orlando
authors.initials: O
authors.lastname: Campos
authors.forename: Antonio Carlos
authors.initials: AC
authors.lastname: de Camargo Carvalho
authors.forename: Angelo Amato Vincenzo
authors.initials: AA
authors.lastname: de Paola
authors.forename: Marcelo Goulart
authors.initials: MG
authors.lastname: Paiva
authors.forename: Julio
authors.initials: J
authors.lastname: Abucham
authors.forename: Valdir Ambrosio
authors.initials: VA
authors.lastname: Moises
mesh_terms: D000328:Adult; D001783:Blood Flow Velocity / Q000187:drug effects / Q000502:physiology; D004452:Echocardiography; D015150:Echocardiography, Doppler; D004562:Electrocardiography; D005260:Female; D005500:Follow-Up Studies; D020249:Hormone Replacement Therapy; D006801:Humans; D007037:Hypothyroidism / Q000000981:diagnostic imaging / Q000188:drug therapy / Q000503:physiopathology*; D008297:Male; D009200:Myocardial Contraction / Q000187:drug effects / Q000502:physiology*; D011446:Prospective Studies; D013318:Stroke Volume / Q000187:drug effects / Q000502:physiology*; D013974:Thyroxine / Q000627:therapeutic use; D013997:Time Factors; D016277:Ventricular Function, Left / Q000187:drug effects / Q000502:physiology
chemical_list: D013974:Thyroxine