During a major illness, the levels of thyroid hormones (T4 and T3) and thyroid stimulating hormone (TSH) change in most patients. These changes do not represent a problem in thyroid gland, but they are part of a larger hormonal reaction that happens at the time of a significant sickness. The most common finding is a low T3 level, as the body shuts down the production of T3 from T4 during sickness. This may also occur after a heart attack. Indeed, 15-20% of patients have low levels of T3 for several days after a heart attack. Patients with the lowest levels of T3 are usually the sickest and have a higher chance of dying.
While most researchers and physicians believe that the hormonal changes during a sickness are helpful and beneficial for recovery, there is debate on whether treatment with T3 may be helpful when it declines to very low levels. In the past, various animal and clinical investigations have been conducted to answer this question. In this study, the authors tried to evaluate the effect of treatment with T3 on recovery from heart attack; specifically, to assess the potential benefits of T3 on the extent of heart muscle damage and its function.
THE FULL ARTICLE TITLE:
Pingitore A et al 2018 Usefulness of triiodothyronine replacement therapy in patients with ST elevation myocardial infarction and borderline/reduced triiodothyronine levels (from the THIRST study). Am J Cardiol. Epub 2018 Dec 18. PMID: 30638544.
SUMMARY OF THE STUDY
This study was done in Pisa, Italy. The authors recruited patients with heart attack who were admitted to cardiac intensive unit. The patients were eligible to enter the study if they had a low level of T3 at the time of admission or a 20% drop in T3 level within the first 72 hours after arrival to hospital.