Recognition of early myocardial infarction by immunohistochemical staining with cardiac troponin-I and complement C9.

The diagnosis of early myocardial infarction (MI) after death, especially in the first few hours (c. 6 h) after the onset of MI, poses a challenge to the forensic pathologists. During this time, the damaged myocardium does not show grossly identifiable morphological changes and may not be recognized even with routine histological microscopic examination. However, the infarcted cardiac tissue releases certain chemicals that can be detected microscopically, two of these being cardiac troponin-I (CT-I) and complement C9 (C9). This study utilizes the importance of these two biomarkers immunohistochemically in an attempt to identify this early phase of MI. This study reveals that the early phase of MI of <6 h duration may be detected through immunohistochemical staining with CT-I and C9. The ischemic/infarcted cardiac myofibers in the <6 h group display reduced/absent CT-I staining as well as positive C9 staining.