Levels of serum thyroxine, triidothyronine and thyrotropin in patients with acute myocardial infarction

OBJECTIVE: To determine the levels of serum thyroxine (T3, T4), triiodothyronine and thyrotropin in patients with acute myocardial infarction (AMI). METHODS: It was an observational prospective study and 60 patients (both males and females) of AMI, (diagnosed by ECG & cardiac enzymes.) were included. Serum thyroid stimulating hormone (TSH), Free T3 and Free T4 were measured and relevant data was entered into a predesigned proforma. RESULTS: FT3 levels were below the reference range in 56.7% cases while both the FT4 and TSH values were found to be the lower limit of normal range. When the decrease in FT3 was correlated with the duration of illness, it was found that significant inverse correlation existed between FT3 value and the duration of illness and linear regression line was obtained. No such correlation existed between FT4 and TSH values. CONCLUSION: Thyroid hormone levels (FT3) decreases in AMI and this change is associated with the duration of illness.