【摘要】 目的 :研究甲状腺激素对犬心房电生理的影响 ,为临床治疗提供帮助 .方法 :2 0只健康家犬 ,随机分为对照组和实验组 (n =10 ) ,实验组用三碘甲状腺氨酸 (T3 ) 15 .0mg·kg-1喂养 ,每日一次 .2 0wk后利用单相动作 (MAP)电位技术 ,研究甲状腺激素对犬在体心脏MAP和心房有效不应期(ERP)的影响 .用放射免疫测定法测定血液中T4和TSH浓度 .结果 :与对照组比较 ,实验组犬的心率和血液T4浓度明显升高 ,而TSH水平明显下降 (P <0 .0 1) ;与对照组心房肌比较 ,实验组犬心房的单相动作电位振幅 (MAPA)无显著性差异 [(18.7± 2 .7)mVvs (2 0 .5± 2 .9)mV ,P >0 .0 5 ];甲状腺激素可引起 5 0 %和 90 %单相动作电位间期 (MAPD50 ,MAPD90 ) [(6 1.3± 9.8) ,(132 .6± 12 .0 )ms]缩短 ,与对照组相比 ,差异具有显著性 [(70 .5± 10 .8) ,(14 1.4± 17.6 )ms,P<0 .0 5 ,P <0 .0 1];实验组犬心房的ERP明显短于对照组[(10 5 .0± 18.3)msvs (12 5 .6± 14 .5 )ms,P <0 .0 1];实验组犬心房ERP/MAPD90 的比值也明显短于对照组 [(0 .80±0 .5 )vs (0 .89± 0 .3) ,P <0 .0 5 ].结论 :甲状腺激素非平行性缩短犬心房的ERP和MAPD90 ,这可能是甲亢患者易发心房颤动的机制之一 .更多还原

【Abstract】 AIM: To investigate the effect of thyroid hormone on the electrophysiological features of atrial cardiomyocytes, and to propose effective therapies for atrial fibrillation (AF) in patients with hyperthyroidism. METHODS: Twenty dogs were randomly divided into control group ( n =10) and experimental group ( n =10). Dogs in experimental group feed by triiodothyronine (T 3), daily doses of 15.0 mg·kg -1 for two weeks. The following electrophysiological parameters were assessed: The atrial effective refractory period (ERP); duration of monophasic action potential at 50% (MAPD 50 ) and 90% (MAPD 90 ) repolarization, amplitude of MAP (MAPA) during sinus rhythm.Serum concentration of T 4 and thyroid stimulating hormone (TSH) were measured by radioimmunoassay. RESULTS: Compared with the control group, serum concentration of T4 and heart rats significantly increased, but serum concentration of TSH significantly decreased in T 3 feed dogs ( P <0.01). Compared with the control atrial cardiomyocytes, thyroid hormone shortened atrial cardiomyocytes MAPD 50 and MAPD 90 , MAPD 61.3±9.8 ms vs 70.5±10.8 ms; MAPD 90 132.6±12.0 ms vs 141.4±17.6 ms, P<0.05, P <0.01), and ERP (105.0±18.3 ms vs 125.6±14.5 ms, P <0.01), ERP/MAPD 90 (0.80±0.5 vs 0.89±0.3, P <0.05) in thyroid hormone group were significantly shorter than that in control group; there were no effects in MAPA between two groups (18.7±2.7 mV vs 20.5±2.9 mV, P >0.05).CONCLUSION: Our data indicate that thyroid hormone nonparallelly shorted ERP and MAPD 90 in dogs.It may be one of the mechanisms of atrial fibrillation in hyperthyroid patients.更多还原