Altered thyroid hormone metabolism in advanced heart failure.

To determine the prevalence and significance of abnormal thyroid hormone metabolism in congestive heart failure, free thyroxine (T4) index, free triiodothyronine (T3) index, reverse T3 and thyrotropin levels were obtained in 84 hospitalized patients with chronic advanced heart failure. Free T4 index was normal in all patients. Free T3 index was reduced or reverse T3 elevated, or both, leading to a low free T3 index/reverse T3 ratio in 49 (58%) of the 84 patients. A low free T3 index/reverse T3 ratio was associated with higher right atrial, pulmonary artery and pulmonary capillary wedge pressures and lower ejection fraction, cardiac index, serum sodium, albumin and total lymphocyte count. In multivariate analysis, the free T3 index/reverse T3 ratio was the only independent predictor of poor 6 week outcome (p less than 0.001); the actuarial 1 year survival rate was 100% for patients with a normal ratio and only 37% for those with a low ratio (p less than 0.0001). A low free T3 index/reverse T3 ratio is associated with poor ventricular function and nutritional status and is the strongest predictor yet identified for short-term outcome in patients with advanced heart failure.