title: [Improvement in functional capacity after levothyroxine treatment in patients with chronic heart failure and subclinical hypothyroidism].
abstract: OBJECTIVE
  To assess whether levothyroxine treatment improves functional capacity in patients with chronic heart failure (New York Heart Association class i-iii) and subclinical hypothyroidism.
  
  
  METHODS
  One hundred and sixty-three outpatients with stable chronic heart failure followed up for at least 6 months were enrolled. A physical examination was performed, and laboratory tests including thyroid hormone levels, Doppler echocardiogram, radionuclide ventriculography, and Holter monitoring were requested. Functional capacity was assessed by of the 6-min walk test. Patients with subclinical hypothyroidism were detected and, after undergoing the s6-min walk test, were given replacement therapy. When they reached normal thyrotropin (TSH) levels, the 6-min walk test was performed again. The distance walked in both tests was recorded, and the difference in meters covered by each patient was analyzed.
  
  
  RESULTS
  Prevalence of subclinical hypothyroidism in patients with heart failure was 13%. These patients walked 292±63m while they were hypothyroid and 350±76m when TSH levels returned to normal, a difference of 58±11m (P<.011). Patients with normal baseline TSH levels showed no significant difference between the 2 6-min walk tests.
  
  
  CONCLUSIONS
  Patients with chronic heart failure and subclinical hypothyroidism significantly improved their physical performance when normal TSH levels were reached.
authors: Unidad de Insuficiencia Cardíaca, Hospital Militar Central, Buenos Aires, Argentina. Electronic address: jorgecurotto@hotmail.com.
authors: Jorge
authors: J
authors: Curotto Grasiosi
authors: Bruno
authors: B
authors: Peressotti
authors: Rogelio A
authors: RA
authors: Machado
authors: Eduardo C
authors: EC
authors: Filipini
authors: Adriana
authors: A
authors: Angel
authors: Jorge
authors: J
authors: Delgado
authors: Gustavo A
authors: GA
authors: Cortez Quiroga
authors: Carmen
authors: C
authors: Rus Mansilla
authors: María del Mar
authors: Mdel M
authors: Martínez Quesada
authors: Alejandro
authors: A
authors: Degregorio
authors: Diego J
authors: DJ
authors: Cordero
authors: Marcelo
authors: M
authors: Dak
authors: Carlos
authors: C
authors: Izurieta
authors: Ricardo J
authors: RJ
authors: Esper
mesh_terms: D000368:Aged; D002317:Cardiovascular Agents / Q000627:therapeutic use; D015897:Comorbidity; D005080:Exercise Test; D005260:Female; D005500:Follow-Up Studies; D006333:Heart Failure / Q000150:complications* / Q000000981:diagnostic imaging / Q000188:drug therapy / Q000503:physiopathology; D006334:Heart Function Tests; D006439:Hemodynamics; D020249:Hormone Replacement Therapy; D006801:Humans; D007037:Hypothyroidism / Q000097:blood / Q000150:complications / Q000188:drug therapy* / Q000503:physiopathology; D008297:Male; D008875:Middle Aged; D011446:Prospective Studies; D013972:Thyrotropin / Q000097:blood; D013974:Thyroxine / Q000097:blood / Q000627:therapeutic use*; D014284:Triiodothyronine / Q000097:blood; D014463:Ultrasonography; D016138:Walking
chemical_list: D002317:Cardiovascular Agents; D014284:Triiodothyronine; D013972:Thyrotropin; D013974:Thyroxine
keywords: Capacidad funcional; Functional capacity; Heart failure; Hipotiroidismo subclínico; Insuficiencia cardíaca; Subclinical hypothyroidism