Abstract:
Background : Troponin T and troponin I have been widely used as specific markers for myocardial injury. Several conditions including muscle injuries (trauma, myositis and rhabdomyolysis), renal failure and hypothyroidism have been associated with elevation of muscle enzymes such as creatine phosphokinase (CPK) and its cardiac isoenzyme (CPK-MB) which can cause problems in the diagnosis of acute myocardial infarction. There is only one study demonstrated no change in the level of serum troponin I in hypothyroid patients. there is no report on troponin T level in this condition. Objective : The objective of this study is to measure troponin T level in hypothyroid patients to prove whether hypothyroid may cause false elevation of troponin T in this condition, which may interfere diagnosis of acute myocardial infarction Design : Cross-sectional descriptive study. Subjects & Method : The patients with hypothyroidism, defined as decreased level of serum free thyroxine (FT4) and increased level of serum thyrotropin (TSH) were enrolled into the study. Serum CPK, CPK-MB. and troponin T were measured in all patients. Result : Sixty-three patients completed the study. Fifty-one were female and twelve were male. The patients' age ranged from 21 to 79 years. (Mean 44.78 ± 14.86 standard deviation). The mean of serum FT4 and TSH were 0.42 ±0.23 and 52.49 ± 32.94 respectively. Serum CPK ranged from 22 to 4,279 U/L (mean 420.71 ± 794.01). and was above the reference range (0-190 U/L) in 27 of 63 patients (42.9 %). Serum CPK-MB ranged from 0.76 to 24.86 ng/ml. (mean 3.42 + 4.37) and was above the reference range (0.1 - 4.94 ng/ml) in 9 of 63 (14.3 %). All of the 63 patients (100 %) had cardiac troponin T level within the reference range (<0.1 ng/ml). Conclusion : Serum troponin T level was not elevated in patients with primary hypothyroidism and could be used in the diagnosis of acute myocardial injury In this condition.