Division of Cardiology, Department of Internal Medicine (W.-H.H., K.-T.S., J.-Y.K., J.-P.T., C.-I.L., C.-C.H., C.-H.S., H.-I.Y., C.-L.H.), MacKay Memorial Hospital, Taipei, Taiwan.
Department of Medicine (K.-T.S., J.-Y.K., J.-P.T., J.-L.L., C.-H.S., H.-I.Y., C.-L.H.), Mackay Medical College, New Taipei City, Taiwan.
Circ Cardiovasc Imaging. 2021 Nov;14(11):e012433. doi: 10.1161/CIRCIMAGING.121.012433. Epub 2021 Nov 16.
Hypothyroidism is reportedly associated with increased cardiovascular risk and heart failure. We aimed to elucidate the mechanistic influence of atrio-ventricular deformations and their prognostic utilizations in asymptomatic subclinical hypothyroidism (SCH).
We assessed speckle-tracking of deformations among 4173 population-based asymptomatic individuals classified as euthyroid (0.25< thyroid-stimulating hormone [TSH] ≤4.0 μIU/mL, n=3799) or having mild (4< TSH ≤10.0 μIU/mL, n=349) or marked (TSH >10 μIU/mL, n=25) SCH. We further related deformational indices to outcomes of atrial fibrillation and heart failure.
Despite borderline differences in indexed left ventricular mass and left atrial volume (=0.054 and 0.051), those classified as mild and marked SCH presented with modest but significant reductions of global longitudinal strain, and showed elevated E/tissue Doppler imaging (TDI)-e', markedly diminished peak atrial longitudinal strain and higher left atrial stiffness (all <0.05) when compared with euthyroid subjects. A higher TSH level was independently associated with reduced TDI-s'/TDI-e', worse global atrio-ventricular strains (global longitudinal strain/peak atrial longitudinal strain), elevated E/TDI-e', and worsened left atrial strain rate components (all <0.05). Over a median 5.6 years (interquartile range, 4.7-6.5 years) follow-up, myocardial deformations yielded independent risk prediction using Cox regression in models adjusted for baseline covariates, N-terminal pro-brain natriuretic peptide, E/e', and treatment effect. Incorporation of global atrio-ventricular strain (global longitudinal strain/peak atrial longitudinal strain) and strain rates further showed improved risk reclassification when added to the baseline TSH strata (classified as euthyroid and mild and marked SCH; all <0.05). Cox regression models remained significant with improved risk reclassification beyond TSH-based strata by using slightly different deformational cutoffs after excluding marked SCH group.
Hypothyroidism, even when asymptomatic, may widely influence subclinical atrio-ventricular mechanical functions that may lead to higher heart failure and atrial fibrillation risk. We proposed the potential usefulness and prognostic utilization of myocardial strains in such population.
甲状腺功能减退症与心血管风险增加和心力衰竭有关。我们旨在阐明房室变形的机制影响及其在无症状亚临床甲状腺功能减退症（SCH）中的预后应用。
我们评估了 4173 名基于人群的无症状个体的斑点追踪变形，这些个体被分类为甲状腺功能正常（0.25<促甲状腺激素 [TSH] ≤4.0 μIU/mL，n=3799）或轻度（4<TSH ≤10.0 μIU/mL，n=349）或明显（TSH>10 μIU/mL，n=25）SCH。我们进一步将变形指数与心房颤动和心力衰竭的结果相关联。
尽管左心室质量和左心房容积的指数差异为临界值（=0.054 和 0.051），但被归类为轻度和明显 SCH 的个体表现出轻微但显著的整体纵向应变降低，并且显示出升高的 E/组织多普勒成像（TDI）-e'，明显降低的峰值心房纵向应变和更高的左心房僵硬度（均<0.05）与甲状腺功能正常的受试者相比。较高的 TSH 水平与降低的 TDI-s'/TDI-e'、更差的整体房室应变（整体纵向应变/峰值心房纵向应变）、升高的 E/TDI-e'和恶化的左心房应变率成分独立相关（均<0.05）。在中位数为 5.6 年（四分位距，4.7-6.5 年）的随访期间， Cox 回归模型在调整基线协变量、N 末端脑利钠肽前体、E/e'和治疗效果后，心肌变形使用 Cox 回归进行独立风险预测。当将整体房室应变（整体纵向应变/峰值心房纵向应变）和应变率纳入基于 TSH 的分层后，风险再分类得到进一步改善（分类为甲状腺功能正常和轻度及明显 SCH；均<0.05）。 Cox 回归模型仍然具有统计学意义，通过在排除明显 SCH 组后使用稍微不同的变形截止值，基于 TSH 的分层之外的风险再分类得到改善。
即使是无症状的甲状腺功能减退症也可能广泛影响亚临床房室机械功能，从而导致更高的心力衰竭和心房颤动风险。我们提出了在这种人群中使用心肌应变的潜在有用性和预后应用。
