Serum values of cardiac Troponin -T in normal and cardiomyopathic dogs

Together with tropomyosin, the troponin complex participates in the contraction of skeletal and cardiac muscles. Troponin is composed of three subunits, namely troponinC (TnC), troponin I (TnI), and troponin T (TnT), which binds tropomyosin. There are three different isoforms of TnT and TnI, two of which are specific for skeletal muscle, while the third is specific for the myocardium (cTnT and cTnI). As the homology between troponins is about 95% among mammals, commercial diagnostic kits designed for use in humans also provide excellent results in other animals. (O’Brien et al., 1997). The absence of detectable cTnT (>0.05 ng/ml) in healthy dogs confirms the utility of this assay in assessing acute myocardial damage, similar to that reported both for both human and veterinary subjects (De Francesco, 2002). The results of the present work indicate the usefulness of the cTnT test for the identification of cardiopathic subjects for whom disease is associated with myocardial damage. Furthermore, our data are also interesting in relation to the lack of correlation between a positive cTnT result and the degree of systolic insufficiency. In addition, the observation that only 50% of the hypokinetic group was positive for cTnT suggests that the assay may have particular utility in discriminating animals with myocardial damage in course from those in which hypokinesis is most likely indicative of a previous injury. On the other hand, the positive test results observed in non-hypokinetic, myocardiopathic subjects implies that the measurement of cTnT is a diagnostic tool that is valuable for the identification of myocardial damage, even in animals that would not otherwise be suspected to have myocardial damage on the basis of clinical and instrumental examination.