FEATURES OF THYROID DYSFUNCTION IN PATIENTS WITH ATRIAL FIBRILLATION.

Abstract

This study explores the prevalence and clinical significance of thyroid dysfunction in patients diagnosed with atrial fibrillation (AF). A total of 134 AF patients (72 males and 62 females) were evaluated using clinical assessments, anthropometric measurements, electrocardiography, Doppler echocardiography, thyroid ultrasound, and thyroid hormone testing (TSH, free T3, free T4, anti-TPO). Participants were grouped according to thyroid gland functional, structural, and autoimmune status. Results indicated that 61.9% had normal thyroid function, whereas 38.1% demonstrated dysthyroidism (subclinical/overt hypothyroidism, subclinical/overt hyperthyroidism, or "pseudo-dysthyroidism"). Notably, hypothyroidism was associated with a higher frequency of severe AF symptoms (EHRA class IV). However, it did not significantly influence AF type (bradysystolic, normosystolic, tachysystolic), AF form (paroxysmal, persistent, permanent), or disease duration. Hyperthyroidism also showed no statistically significant effect on AF type, form, or duration, though there was a trend toward more severe symptoms (EHRA III-IV). The study emphasizes the importance of "pseudo-dysthyroidism," a condition marked by secondary alterations in thyroid hormone levels due to other comorbid illnesses. Recognizing such cases is critical to prevent unnecessary thyroid-directed interventions. Overall, the findings suggest that thyroid dysfunction-particularly hypothyroidism-may exacerbate symptom severity in AF without necessarily altering the arrhythmia's fundamental characteristics. Comprehensive thyroid evaluation, including hormone measurements and ultrasound, is recommended for all AF patients to detect both overt and subclinical thyroid disorders and guide appropriate management.