Objective: A number of different hormone changes have been described during the acute myocardial infarction (AMI), including those of the non-thyroidal illness syndrome (NTIS).
Design and methods: We assessed the alterations of serum thyroid hormones, cytokines and cortisol levels in 30 patients with a first episode of AMI 4, 24, 48h and 10 days (240h) after the onset of the chest pain and we investigated the possible relationship of these alterations with the severity of AMI.
Results: Fifteen patients had left ventricular ejection fraction (LVEF) </=50% (group I) and 15 patients had LVEF >50% (group II). A transient decrease of total tri-iodothyronine (T(3)), more prominent in group I (P<0.05, t-test) with a concomitant rise of reverse T(3 )(rT(3)) occurred at 24h. Total thyroxine (T(4)), free T(4) (FT(4)) and free T(4) index did not change significantly, but tended to be higher in group I patients, whereas TSH significantly increased in group II at 48h. Interleukin-6 (IL-6) increased significantly at 24h only in group I and declined thereafter (24 vs 240h, P<0.001) and this temporal change of IL-6 was associated with similar changes of creatine phosphokinase and creatine kinase isoenzyme MB (CK-MB). Tumor necrosis factor-alpha and IL-1beta remained low in both groups. Cortisol was higher at 4h and in 12 patients was above the normal values. Negative correlation was found between LVEF and IL-6 (P<0. 001), whereas T(3), T(4) or cortisol levels were not correlated with the LVEF.
Conclusions: Our data indicate that NTIS, in association with increase of IL-6, occurs in the early post-infarction period. In the NTIS following AMI the high level of IL-6 is the best predictor, among several parameters, of the severity of AMI as assessed by the LVEF and the rise of CK-MB.