Troponin I as a specific marker for heart damage after heart transplantation in a patient with becker type muscular dystrophy.

In a patient with Becker type muscular dystrophy, the development of cardiomyopathy may require heart transplantation, and during both the perioperative period and later it is useful to determine whether myocardial cell damage is occurring; however, the measurement of serum levels of creatine kinase (CK), MB isoenzyme, is not useful because that isoenzyme is released by the dystrophic skeletal muscle, as well as damaged myocardium. Because cardiac troponin I (cTn I) seems to be quite specific for myocardial cells, we reasoned that measurement of serum levels of this protein could distinguish between myocardial damage and skeletal muscle disease in this patient during and after transplantation. During the immediate postoperative period, the time course of the release of total CK (tCK), CK MB mass, myoglobin, and cTn I were different, yielding a peak within 4 hours for CK MB, 24 hours for myoglobin and 36 hours for tCK and cTn I. During the first postoperative year, the patient displayed a release of tCK, CK MB, and myoglobin; cTn I was constantly lower than the reference value for cardiac myocyte necrosis, suggesting the presence of a continuous muscular damage without any myocardial involvement and an accurate specificity of cTn I to differentiate between myocardial and muscular cell damage in patients with neuromuscular disorders.