Acute coronary ischemia: troponin I and T

Abstract

Despite advances in diagnosis and management, ischemic heart disease remains the leading cause of death in the USA. Serum cardiac enzymes, one of the three fundamental criteria for establishing the diagnosis of myocardial infarction, are not specific for cardiac muscle and have a narrow time-window. The recent development of monoclonal antibodies to cardiac troponin I and troponin T has resulted in cardiac-specific assays. Several published studies have documented the utility of troponin proteins in the evaluation of myocardial necrosis. A brief overview of the characteristics and clinical utility of troponin T and I is presented here.

Cardiac troponin I in canine patients with lymphoma and osteosarcoma receiving doxorubicin: comparison with clinical heart disease in a retrospective analysis

“…Currently available methods in human medicine are either non‐invasive but lack specificity and/or sensitivity [echocardiography, electrocardiography, physical examination (PE) and radionuclide angiocardiography], or are fairly specific and sensitive, but invasive (endomyocardial biopsy) (Singal & Iliskovic, 1998). The troponins are muscle proteins that offer a sensitive and specific measure of myocyte damage (Sacks, 1999). Troponin is part of the thin filament of the contractile apparatus of muscle that is composed of three subunits: T, C and I.…”

“…Troponin is part of the thin filament of the contractile apparatus of muscle that is composed of three subunits: T, C and I. Most cardiac troponin I (cTnI) is structurally bound with only 2–4% in the cytosolic pool and is a marker for cardiac myocyte death (Dean, 1998; Sacks, 1999). Its function is to mediate the interaction between actin and myosin, inhibiting muscle contraction.…”

“…Normal heparinized plasma concentrations for canine and feline cTnI have been established on two assays, but there are many commercially available assays (Sleeper et al ., 2001; Oyama et al ., 2003). There is a lack of standardization among cTnI assays, each using different antibodies and levels of sensitivity (Sacks, 1999). Although serum cTnT concentrations were increased in two dogs at the completion of doxorubicin chemotherapy, use of cTnI as a marker of chemotherapy‐related cardiac damage has not been reported in clinical veterinary medicine (DeFrancesco et al ., 2002).…”