Mejoría de la capacidad funcional tras tratamiento con levotiroxina en pacientes con insuficiencia cardíaca crónica e hipotiroidismo subclínico / Improvement in functional capacity after levothyroxine treatment in patients with chronic heart failure and subclinical hypothyroidism

OBJETIVO: Evaluar si el tratamiento con levotiroxina mejora la capacidad funcional en pacientes con insuficiencia cardíaca crónica clase funcional i-iii de la New York Heart Association e hipotiroidismo subclínico. MÉTODOS: Se incluyeron 163 pacientes ambulatorios con insuficiencia cardíaca crónica estable y con un mínimo de seguimiento de 6 meses. Se realizó un examen clínico y se solicitaron pruebas de laboratorio que incluyeron hormonas tiroideas, ecocardiograma con doppler, ventriculografía radioisotópica y un estudio Holter. La capacidad funcional se evaluó por medio de una caminata de 6min. Se detectaron los pacientes con hipotiroidismo subclínico que recibieron tratamiento sustitutivo y, una vez con valores normales de tirotropina (TSH), se les realizó una nueva caminata de 6min. Se registraron los metros recorridos en cada prueba y se analizó la diferencia de los metros caminados en cada paciente. RESULTADOS: Observamos una prevalencia de hipotiroidismo subclínico del 13% en pacientes con insuficiencia cardíaca. Mientras se encontraban hipotiroideos, los metros recorridos fueron de 292 ± 63, y una vez alcanzados valores normales de TSH, de 350 ± 76. La diferencia en metros fue de 58 ± 11 (p < 0,011). Los pacientes con valores normales de TSH no mostraron diferencias significativas entre las 2 pruebas. CONCLUSIONES: Los pacientes con insuficiencia cardíaca crónica e hipotiroidismo subclínico, una vez eutiroideos, mejoraron de forma significativa su rendimiento físico

AIM: 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 ± 63 m while they were hypothyroid and 350 ± 76m when TSH levels returned to normal, a difference of 58 ± 11 m (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

[Improvement in functional capacity after levothyroxine treatment in patients with chronic heart failure and subclinical hypothyroidism]. / Mejoría de la capacidad funcional tras tratamiento con levotiroxina en pacientes con insuficiencia cardíaca crónica e hipotiroidismo subclínico.

AIM: 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.