Effects of L-thyroxine on cardiac function and β receptor responsibility in congestive heart failure

doi:10.3969/j.issn.1002-1949.2001.01.008

Abstract：Objective　To observe the effects of L-thyr oxine on cardiac function and β response to dobutamine of congestive heart fail ure(CHF).Methods　A total of 23 patients with CHF were enr olled in the study.10 patients were randomizely assigned to control group with general treatment,13 pat ients assigned as treatment group were administered L-thyroxine (100 μg/day,orally)for two weeks.Clinical signs and symptoms of hyperthyroidism were recorded at all study period,before and at the end of study period of treatment,every patie nt was measured plasma levels of T3、T4、TSH and free T3、free T4、rT3 .A 12-lead electrocardiogram were recorded,echocardiogram was examined to evaluate index of cardiac function,dobutamine was infused intraveneously to evaluate cardiac response to the adrenergic stimulation.Results　All patients had no clinical signs and symptoms of hyperthyroidism,cardiac function class were improved in two groups,but treatment group had better improved than c ontrol group.Plasma T4 level was obviously increased but TSH level has reduced after L-thyroxine treatment (P＜0.01 and P＜0.05).Echocardiogram was found cardiac function of two groups had improved,but left ventricular end-diastolic diameter of treatment group had markedly changed compared with control group .Dobutamine infusion was showed heart rate after treatment had significant differences in two groups compared with befo re treatment(P＜0.05).Conclusions　L-thyroxine was well tolerated,and no adverse effects.Cardiac function and left ventricular end-diasto lic diameter had improved in CHF patients. Therefore, administration of L-thyro xine might be helped in a short term.