Low triiodothyronine and exercise capacity in heart failure.
BACKGROUND
Cardiopulmonary exercise test (CPT) has a prominent value in assessing clinical severity in chronic heart failure (HF) patients. Reduced free triiodothyronine (fT3) plasma level is associated with a more severe disease and prognosis. The aim of this study was to evaluate the relationship between low fT3 plasma level and reduced exercise capacity in chronic HF, and to determine the influence of a low T3 status in subsets of patients with different functional impairment.


RESULTS
240 HF patients (79% males; age 62 ± 12 years, mean ± standard deviation; left ventricular ejection fraction, EF, 30 ± 9%) underwent a CPT, clinical and neurohormonal characterization (assay for plasma brain natriuretic peptide, BNP, norepinephrine, aldosterone, renin activity, fT3, free T4, thyroid-stimulating hormone). At multivariate analysis in the whole population, age, gender and BNP level were independently associated with peak VO2, whereas in patients with severe functional impairment (peak VO2 < 14 ml/min/kg) fT3 resulted independently related to peak VO2, together with gender and BNP. When patients with peak VO2 < 14 ml/min/kg were divided according to fT3 levels, patients with low T3 syndrome showed reduced exercise capacity and worse ventilatory efficiency.


CONCLUSIONS
BNP and fT3 are independently associated with exercise capacity in severely compromised HF patients.
Fontana
Marianna
M
Division of Cardiovascular Medicine, Fondazione G. Monasterio CNR-Regione Toscana, Pisa, Italy.
Passino
Claudio
C
Poletti
Roberta
R
Zyw
Luc
L
Prontera
Concetta
C
Scarlattini
Maria
M
Clerico
Aldo
A
Emdin
Michele
M
Iervasi
Giorgio
G
D000368:Aged; D015415:Biomarkers; D002302:Cardiac Output / Q000502:physiology; D015444:Exercise / Q000502:physiology; D005080:Exercise Test; D017079:Exercise Tolerance / Q000502:physiology*; D005260:Female; D006333:Heart Failure / Q000175:diagnosis / Q000378:metabolism* / Q000503:physiopathology*; D006801:Humans; D008297:Male; D008875:Middle Aged; D010101:Oxygen Consumption / Q000502:physiology; D012720:Severity of Illness Index; D013318:Stroke Volume / Q000502:physiology; D013972:Thyrotropin / Q000097:blood; D013974:Thyroxine / Q000097:blood; D014284:Triiodothyronine / Q000172:deficiency*
D015415:Biomarkers; D014284:Triiodothyronine; D013972:Thyrotropin; D013974:Thyroxine