Department of Cardiovascular Medicine, The University of Tokyo, Tokyo, Japan.
Department of Clinical Laboratory, The University of Tokyo, Tokyo, Japan.
J Clin Endocrinol Metab. 2021 Mar 25;106(4):e1859-e1867. doi: 10.1210/clinem/dgaa730.
Although subclinical hypothyroidism (SCH) is a common clinical entity and carries independent risk for incident heart failure (HF), its possible association with subclinical cardiac dysfunction is unclear. Left ventricular global longitudinal strain (LVGLS) and left atrial (LA) phasic strain can unmask subclinical left heart abnormalities and are excellent predictors for HF. This study aimed to investigate the association between the presence of SCH and subclinical left heart dysfunction in a sample of the general population without overt cardiac disease.
We examined 1078 participants who voluntarily underwent extensive cardiovascular health check-ups, including laboratory tests and 2-dimensional speckle-tracking echocardiography to assess LVGLS and LA reservoir, conduit, and pump strain. SCH was defined as an elevated serum thyroid-stimulating hormone level with normal concentration of free thyroxine.
Mean age was 62 ± 12 years, and 56% were men. Seventy-eight (7.2%) participants exhibited SCH. Individuals with SCH had significantly reduced LA reservoir (37.1 ± 6.6% vs 39.1 ± 6.6%; P = 0.011) and conduit strain (17.3 ± 6.3% vs 19.3 ± 6.6%; P = 0.012) compared with those with euthyroidism, whereas there was no significant difference in left ventricular ejection fraction, LA volume index, LVGLS, and LA pump strain between the 2 groups. In multivariable analyses, SCH remained associated with impaired LA reservoir strain, independent of age, traditional cardiovascular risk factors, and pertinent laboratory and echocardiographic parameters. including LVGLS (standardized β -0.054; P = 0.032).
In an unselected community-based cohort, individuals with SCH had significantly impaired LA phasic function. This association may be involved in the higher incidence of HF in subjects with SCH.
尽管亚临床甲状腺功能减退症（SCH）是一种常见的临床实体，且独立增加心力衰竭（HF）的发病风险，但SCH 与亚临床心功能障碍的可能关联尚不清楚。左心室整体纵向应变（LVGLS）和左心房（LA）相应变可以揭示亚临床左心异常，是 HF 的极佳预测指标。本研究旨在调查无明显心脏疾病的一般人群样本中，SCH 的存在与亚临床左心功能障碍之间的关系。
我们检查了 1078 名自愿接受广泛心血管健康检查的参与者，包括实验室检查和二维斑点追踪超声心动图，以评估 LVGLS 和 LA 储备、传导和泵应变。SCH 定义为血清促甲状腺激素水平升高，游离甲状腺素浓度正常。
平均年龄为 62±12 岁，56%为男性。78 名（7.2%）参与者表现出 SCH。与甲状腺功能正常者相比，SCH 个体的 LA 储备应变（37.1±6.6%比 39.1±6.6%；P=0.011）和传导应变（17.3±6.3%比 19.3±6.6%；P=0.012）显著降低，而左心室射血分数、LA 容积指数、LVGLS 和 LA 泵应变在两组间无显著差异。多变量分析显示，SCH 与 LA 储备应变受损独立相关，与年龄、传统心血管危险因素以及相关的实验室和超声心动图参数无关，包括 LVGLS（标准化β-0.054；P=0.032）。
在未选择的基于社区的队列中，SCH 个体的 LA 相功能明显受损。这种相关性可能与 SCH 患者 HF 发生率较高有关。
