Department of Cardiology, Giresun University Medical Faculty, Giresun, Turkey.
Eur Rev Med Pharmacol Sci. 2022 May;26(10):3677-3685. doi: 10.26355/eurrev_202205_28863.
Subclinical hypothyroidism (SH) is a biochemical definition that has been proven to be associated with cardiovascular diseases. Fragmented QRS (fQRS) is defined as an electrocardiographic (ECG) reflection of cardiac fibrosis. It is associated with increased cardiovascular mortality and morbidity. In this study, we aim to evaluate the presence and frequency of fQRS in SH patients and determine the relationship between fQRS presence and left ventricular dysfunction by using the myocardial performance index (MPI).
Our study included 50 newly diagnosed SH and 50 healthy participants with similar demographic characteristics. We compared demographic characteristics, laboratory findings, electrocardiographic and echocardiographic measurements of the study population. SH patients were evaluated as two groups in the subgroup analysis: [fQRS(+) SH] with fQRS and [fQRS(-) SH] without fQRS. We analyzed the correlation of thyroidstimulating hormone (TSH) levels with demographic characteristics, electrocardiographic and echocardiographic data. Independent predictors of fQRS presence were evaluated by logistic regression analysis.
The mean age of SH patients was 44 ± 8 years, and 46% (n = 23) of the patients were women. In the control group, the mean age was 45 ± 11 years, and 52% (n = 26) of the participants were women. MPI was found to be significantly higher in the SH group compared to the control group (0.53 ± 0.07 vs. 0.41 ± 0.08, p< 0.001). fQRS was found to be significantly higher in the SH group compared to the control group (p= 0.004). In echocardiographic measurements, isovolumic relaxation time (IVRT) was found to be significantly longer in the fQRS(+) SH group (105.6 ± 21.8 ms vs. 91.1 ± 24.4 ms, p < 0.001), while isovolumic contraction time (IVCT) was not significantly different between the groups. Ejection time (ET) was significantly longer in the fQRS (-) SH group (286.9 ± 32.1 ms vs. 274.2 ± 30.6 ms; p = 0.011). MPI was 0.57 ± 0.12 in the fQRS (+) SH group and 0.48 ± 0.06 in the fQRS (-) SH group, which was significantly higher (p = 0.001). TSH was found to be 8.82 ± 4.58 in fQRS (+) SH group and 5.73 ± 3.10 in fQRS (-) SH group (p = 0.003). It was found that MPI (r = 0.302, p < 0.001) and fQRS (r = 0.321, p < 0.001) were significantly positively correlated with TSH. TSH levels [OR = 1,645, 95% CI = 1,322 to 2,067 (p = 0.001)], IVRT [OR = 1,502, 95% CI = 1,119 to 95% (p = 0.003)], and MPI [OR = 1,408, 95% CI = 0.989 - 1.806 (p = 0.001)] were found to be independent predictors of the presence of fQRS.
The frequency of fQRS in SH patients was found to be higher than in the healthy population. MPI values were higher in fQRS (+) SH patients compared to fQRS (-) SH patients, resulting indirectly having a higher risk of tendency to left ventricular systolic/diastolic dysfunction. MPI and fQRS had a significant positive correlation with TSH. TSH, IVRT, and MPI were found to be independent predictors of the presence of fQRS in SH patients.
亚临床甲状腺功能减退症（SH）是一种已被证明与心血管疾病相关的生化定义。碎裂 QRS 波（fQRS）定义为心电图（ECG）对心肌纤维化的反映。它与心血管死亡率和发病率增加有关。在这项研究中，我们旨在评估 SH 患者中 fQRS 的存在和频率，并通过使用心肌做功指数（MPI）确定 fQRS 存在与左心室功能障碍之间的关系。
我们的研究包括 50 例新诊断的 SH 和 50 例具有相似人口统计学特征的健康参与者。我们比较了研究人群的人口统计学特征、实验室发现、心电图和超声心动图测量值。在亚组分析中，SH 患者分为两组：有 fQRS 的 [fQRS（+）SH] 和没有 fQRS 的 [fQRS（-）SH]。我们分析了促甲状腺激素（TSH）水平与人口统计学特征、心电图和超声心动图数据的相关性。通过逻辑回归分析评估 fQRS 存在的独立预测因子。
SH 患者的平均年龄为 44 ± 8 岁，其中 46%（n = 23）为女性。对照组的平均年龄为 45 ± 11 岁，其中 52%（n = 26）为女性。与对照组相比，SH 组的 MPI 明显更高（0.53 ± 0.07 对 0.41 ± 0.08，p<0.001）。与对照组相比，SH 组的 fQRS 明显更高（p=0.004）。在超声心动图测量中，fQRS（+）SH 组的等容舒张时间（IVRT）明显较长（105.6 ± 21.8 ms 对 91.1 ± 24.4 ms，p < 0.001），而两组的等容收缩时间（IVCT）无明显差异。fQRS（-）SH 组的射血时间（ET）明显较长（286.9 ± 32.1 ms 对 274.2 ± 30.6 ms；p = 0.011）。fQRS（+）SH 组的 MPI 为 0.57 ± 0.12，fQRS（-）SH 组为 0.48 ± 0.06，明显更高（p = 0.001）。fQRS（+）SH 组的 TSH 为 8.82 ± 4.58，fQRS（-）SH 组为 5.73 ± 3.10（p = 0.003）。发现 MPI（r = 0.302，p < 0.001）和 fQRS（r = 0.321，p < 0.001）与 TSH 呈显著正相关。TSH 水平 [OR = 1.645，95% CI = 1.322 至 2.067（p = 0.001）]、IVRT [OR = 1.502，95% CI = 1.119 至 95%（p = 0.003）]和 MPI [OR = 1.408，95% CI = 0.989 至 1.806（p = 0.001）]被发现是 fQRS 存在的独立预测因子。
SH 患者的 fQRS 频率高于健康人群。与 fQRS（-）SH 患者相比，fQRS（+）SH 患者的 MPI 值更高，这间接导致左心室收缩/舒张功能障碍的风险增加。MPI 和 fQRS 与 TSH 呈显著正相关。TSH、IVRT 和 MPI 是 SH 患者 fQRS 存在的独立预测因子。
