Euthyroid Sick Syndrome in Acute Ischemic Syndromes

Abstract

The purposes of this study were to assess the occurrence of euthyroid sick syndrome in patients with acute myocardial infarction (AMI) or unstable angina (UA), and the relationship with beta-blocker or thrombolytic therapy. Plasma triiodothyronine (T3), reverse T3 (rT3), free T3 (FT3), thyroxine (T4), free T4 (FT4), thyroid-stimulating hormone (TSH), thyroxine-binding globulin (TBG), and albumin (ALB) levels were determined in 95 patients (59 males, 36 females, aged 58.4+/-9) with AMI and 19 patients (13 males, 6 females aged 54.7+/-12.3) with UA for 5 consecutive days from the onset of the acute syndrome and 1 month later. Patients were divided according to beta-blocker therapy and thrombolytic therapy. There was a significant T3 decrease and rT3 increase in all patients during the first 5 days following admission (p < 0.05). FT3 and FT4 remained unchanged during the study. In patients with complicated infarctions, the rT3 increase and the T3 decrease were significantly greater compared to those with uncomplicated infarctions (p<0.03). TSH, T4, TBG, and ALB were significantly (p<0.05) decreased only in complicated infarctions. No differences were observed between patients with or without thrombolysis or patients with or without beta-blocker treatment. The apparent decrease in T3, the increase in rT3 levels and the decreased TSH and T4 levels, show clearly that the euthyroid sick syndrome (low T3) occurs not only in AMI but also in UA. In addition, these hormonal changes are not affected by beta-blocker therapy and thrombolysis does not influence the occurrence of the syndrome. The degree of T3 decrease is proportional to the severity of cardiac damage and may have a possible prognostic value.

The Prevalence of Low T3 With Arrhythmia and Heart Failure in Patients With Acute Coronary Syndrome

“…Low TT3 levels were also present in USAP and AMI. 7 We found that the mean TT3 values in USAP patients were similar to those in patients with AMI.…”

“…2 Since in prior studies, thyroid hormone changes within days of the acute phase were parallel to the values at the first day of acute phase, we measured thyroid hormones only at the first day in our study. 7,8 Measurement of reverse T3 was not performed. Because reverse T3 does not reliably differentiate hypothyroidism from NTI, 2,9 there were no patients with low T4.…”

“…19,20 These observations support the opinion that ESS may be a protective or adaptive event in severe illnesses. [2][3][4]7,21 There is a change in TSH and thyroid hormone production in the elderly. 22 There was also a negative correlation between age and TT3 value in our study.…”

Perfil dos hormônios tireoidianos nas síndromes coronarianas agudas

“…These findings were consistent with those found in the "euthyroid sick syndrome". No significant difference between unstable angina and acute myocardial infarction was found in thyroid hormone plasma levels 14 . Our criticism regarding this study is that beta-blockers affect peripheral conversion of T4 to T3.…”

“…This hormonal profile is consistent with the "euthyroid sick syndrome". Hormonal variations were independent of the use of thrombolytics and beta-blockers 14 …”