Relationship Between Total Atrial Conduction Time and Epicardial Adipose Tissue in Patients With Subclinical Hypothyroidism

Abstract

Subclinical hypothyroidism (SCH) is characterized by elevated thyroid -stimulating hormone (TSH) levels with normal free thyroxine (fT4) levels. It is associated with increased cardiovascular risk, necessitating regular monitoring of cardiovascular parameters. This study investigated the relationship between total atrial conduction time (TACT) and epicardial adipose tissue (EAT) in patients diagnosed with SCH, aiming to identify potential cardiovascular risks. An observational cross-sectional study was conducted at Van Yüzüncü Yıl University from January 2024 to January 2025. Fifty-four patients with SCH (TSH levels 5.0-10 μIU/mL, normal fT4) were compared to fifty-four healthy controls. Echocardiographic measurements, including EAT thickness and TACT, were obtained. No significant differences were found between groups regarding age, gender, and various laboratory parameters. TSH levels were significantly higher in the patient group 7.39±1.29 μIU/mL compared to control s 2.33±0.93 μIU/mL, p=0.001; EAT 6.74±0.96 mm vs. 4.73±0.41 mm, p=0.001 and TACT 122±8.70 ms vs. 87.8±5.33 ms, p=0.001 were also significantly elevated in SCH patients. A strong positive correlation was observed between EAT and TACT (r=0.895, p=0.001) as w ell as between TSH and both EAT and TACT (r=0.701, p=0.001; r=0.822, p=0.001). SCH patients exhibit significantly increased EAT and TACT levels compared to healthy controls, indicating a heightened risk for adverse cardiovascular outcomes. The strong correlation between TSH, EAT, and TACT underscores the importance of monitoring TSH levels and suggests that proactive management of SCH may mitigate cardiovascular risks.