The purpose of this study was to investigate whether thyroid hormone levels have 
any predictive value for mortality in patients presenting to the emergency 
department with acute myocardial infarction (AMI). Three groups of patients 
admitted to the emergency department within the 11-month study period were 
considered eligible: 95 patients with chest pain and proven AMI, 26 patients 
with chest pain and no AMI, and 114 patients who served as controls with no 
evidence of any major disease. Cardiac enzymes and the following thyroid 
hormones were analyzed and compared between groups, regarding effects of 
historical and demographic factors: thyrotrophin, free triiodothyronine (FT3), 
total triiodothyronine (TT3), free thyroxine (FT4), and total thyroxine (TT4). 
Sixteen patients with AMI (16.8%) died within the study period. Troponin T and 
creatine kinase-B with an M-type subunit levels were significantly higher in the 
nonsurvivors when compared with survivors. Survivors in the AMI group had higher 
TT3, TT4, and lower FT4 levels, while the nonsurvivors in the AMI group had 
higher thyrotrophin and lower TT3, FT3 and FT4 levels than controls. In the AMI 
group, the nonsurvivors had lower TT3 and FT3 levels than the survivors. A 
history of diabetes mellitus and/or angina, TT3, or FT3 was an independent 
predictor of mortality. TT3 and FT3 appear to be independent prognostic factors 
in patients with AMI.