[Evaluation of thyroid function after myocardial infarction]

The myocardial infarction (M.I.) constitutes an exemplary acute severe affection able to modifie hormonal concentrations. The total and unbound thyroid hormones, reverse T3 (rt3), TSH, and cortisolemia were determined in 24 patients during a period of 21 days in order to compare them to different markers of severity of MI. The initial phase of the disease is characterized by low concentrations of total and free T3 and high concentrations of rT3 combined with more often than not normal total and free T4 and TSH values contrasting with an increase in cortisol levels. The abnormalities were more pronounced the day after admission and then progressively amend. There are several statistic relationship between the marker of severity of MI and thyroid hormones. In the same way total T3 is all the more decreased especially since myoglobin, CPK-MB, ST amplitude and ventricle ejection fraction are more disturbed. Severe forms of MI induces a pseudo central thyroid insufficiency with low T3, low T4 and a tendency to TSH decrease. Total T3 blood levels may usefully contribute to the elaboration of an MI severity index.