Effects of thyroxine on cardiac function and lymphocyte beta-adrenoceptors in patients with chronic congestive heart failure
Lu, X.; Huang, J.; Zhang, X.; Li, X.; Wang, C.; Zhang, P.; Chen, Y.
Chinese Medical Journal 116(11): 1697-1700
2003
ISSN/ISBN: 0366-6999 PMID: 14642140 Document Number: 552314
Objective: To explore the effects of thyroid hormone (TH) on cardiac function and peripheral lymphocyte beta-adrenoceptors (beta-ARs) of patients with chronic congestive heart failure (CHF). Methods: Twenty-eight patients with class III or IV advanced CHF due to dilated cardiomyopathy (DCM) or ischemic cardiomyopathy (ICM) were randomly divided into groups A and B. L-thyroxine (L-T50) was administered to group B. Exercise tolerance, chest X-rays, and echocardiographic parameters were obtained before and after one month of treatment, Ficoll-hypaque solution was used to separate peripheral lymphocytes, and 125I-pindolol radioligand binding was used to measure beta-AR levels in peripheral lymphocytes. Results: L-T50 therapy improved cardiac output (CO, (2.98+-0.31) L/min vs (3.24+-0.28) L/min, P<0.01), left ventricular ejection fraction (LVEF, 26.21+-3.21% vs 37.93%+-9.01%, P<0.01), and decreased isovolumetric relaxation time (IVRT, 0.12+-0.04 vs 0.10+-0.02, P<0.01). Serum TH levels and the maximal number of beta-AR binding sites (betamax) in peripheral lymphocytes were lower in patients with CHF than in normal healthy people, but L-T50 administration induced a beta-AR up-regulation on peripheral lymphocyte surfaces. L-T50 was well tolerated without episodes of ischemia or arrhythmia. There was no significant change in heart rate or metabolic rate. Conclusion: TH administration improves cardiac function and beta-AR expression in peripheral lymphocytes of patients with CHF.