Osman Faizel, Franklyn Jayne A, Daykin Jacqueline, Chowdhary Saqib, Holder Roger L, Sheppard Michael C, Gammage Michael D
Division of Medical Sciences, University of Birmingham, Queen Elizabeth Hospital, Birmingham B15 2TH, United Kingdom.
Am J Cardiol. 2004 Aug 15;94(4):465-9. doi: 10.1016/j.amjcard.2004.04.061.
Patients with subclinical and treated overt hyperthyroidism have an excess vascular mortality rate. Several symptoms and signs in overt hyperthyroidism suggest abnormality of cardiac autonomic function that may account in part for this excess mortality rate, but few studies have examined cardiac autonomic function in untreated and treated hyperthyroidism. We assessed heart rate turbulence (HRT) and time-domain parameters of heart rate variability in a large, unselected cohort of patients with overt hyperthyroidism referred to our thyroid clinic (n = 259) and compared findings with a group of normal subjects with euthyroidism (n = 440). These measures were also evaluated during antithyroid therapy (when serum-free thyroxine and triiodothyronine concentrations returned to normal but thyrotropin remained suppressed (i.e., subclinical hyperthyroidism, n = 110) and when subjects were rendered clinically and biochemically euthyroid (normal serum thyrotropin, free thyroxine and triiodothyronine concentrations, n = 219). We found that overall measures of heart rate variability and those specific for cardiac vagal modulation were attenuated in patients with overt hyperthyroidism compared with normal subjects; measurements of overall heart rate variability remained low in those with low levels of serum thyrotropin but returned to normal in patients with biochemical euthyroidism. Measurements of HRT (onset and slope) were also decreased in patients with overt hyperthyroidism, but HRT slope returned to normal values with antithyroid treatment. This study is the first to evaluate HRT in overt and treated hyperthyroidism.
亚临床甲亢患者和已接受治疗的显性甲亢患者的血管性死亡率较高。显性甲亢的一些症状和体征提示心脏自主神经功能异常，这可能部分解释了这种较高的死亡率，但很少有研究探讨未经治疗和已接受治疗的甲亢患者的心脏自主神经功能。我们评估了一大组转诊至我们甲状腺门诊的未经过筛选的显性甲亢患者（n = 259）的心率震荡（HRT）和心率变异性的时域参数，并将结果与一组甲状腺功能正常的正常受试者（n = 440）进行比较。在抗甲状腺治疗期间（当血清游离甲状腺素和三碘甲状腺原氨酸浓度恢复正常但促甲状腺激素仍被抑制时，即亚临床甲亢，n = 110）以及当受试者达到临床和生化甲状腺功能正常状态时（血清促甲状腺激素、游离甲状腺素和三碘甲状腺原氨酸浓度正常，n = 219），也对这些指标进行了评估。我们发现，与正常受试者相比，显性甲亢患者的心率变异性总体指标以及心脏迷走神经调节的特异性指标均减弱；血清促甲状腺激素水平低的患者心率变异性总体测量值仍较低，但生化甲状腺功能正常的患者则恢复正常。显性甲亢患者的HRT（起始和斜率）测量值也降低，但抗甲状腺治疗后HRT斜率恢复到正常值。本研究是首次评估显性和已接受治疗的甲亢患者的HRT。
