Evaluation Of the Thyroid Function Test in Cardiac Failure Patients: A Cross-Sectional Study

Background: The cardiovascular system is influenced by thyroid hormones.  Hyperthyroidism can result in atrial arrhythmias, hypertension, and cardiac failure; hypothyroidism can cause hyperlipidemia and ventricular arrhythmias.  However, these disorders can usually be reversed by addressing the underlying thyroid problem.  We looked into the relationship between thyroid levels within the reference range and heart failure.

Methodology: A descriptive, cross-sectional study was conducted on 100 heart failure patients of age greater than 18 years, New York Heart Association (NYHA) II-IV. The demographic details were collected, and Serum TSH, free T3, and free T4 were investigated.

Data were analyzed by standard statistical software.

Results: Out of 100 patients, 64 were males and 36 were females, with a mean age of 42.97 ± 11.07 years. Forty-eight patients belonged to NYHA class II, 30 patients to class III, and 22 patients to class IV. The majority of the patients (51) had an ejection fraction of 31-35%. Low T3 syndrome was seen in 49 patients, followed by subclinical hypothyroidism in 17 patients. The majority (68.1%) of the NYHA class IV patients had TSH levels of >4.2mcIU/ml. Free T3 and free T4 levels were within the reference range in all classes of patients. In patients with a lower ejection fraction (<30%), 56% of patients had a TSH level of 0.4-4.2 mIU/mL.

Conclusion: In patients with pre-existing heart failure, subclinical hypothyroidism with TSH ≥ 4.2 mIU/L and isolated low T3 levels are associated with poor prognosis. Furthermore, studies are required to explore the therapeutic effects of T4 and T3 administration in heart failure.