tnt and tni in cardiac muscle are presented by forms different from those in skeletal muscles. two isoforms of tni and two isoforms of tnt are expressed in human skeletal muscle tissue (sktni and sktnt). only one tissue-specific isoform of tni is described for cardiac muscle tissue (ctni), whereas the existence of several cardiac specific isoforms of tnt (ctnt) are described in the literature. no cardiac specific isoforms are known for human tnc. tnc in human cardiac muscle tissue is presented by an isoform typical for slow skeletal muscle. another form of tnc, fast skeletal tnc isoform, is more typical for fast skeletal muscles. ctni is expressed only in myocardium. no examples of ctni expression in healthy or injured skeletal muscle or in other tissue types are known. ctnt is probably less cardiac specific. expression of ctnt in skeletal tissue of patients with chronic skeletal muscle injuries has been described.