Early pathologic detection of acute myocardial infarction

Area of Science:

• Cardiovascular pathology
• Histochemistry
• Ischemic injury research

Background:

• Tetrazolium stains, like triphenyltetrazolium chloride (TTC), are increasingly used for early myocardial infarction detection.
• The accuracy of TTC in identifying infarction before distinct histologic necrosis is established remains unclear.

Purpose of the Study:

• To evaluate the reliability of TTC staining in delineating myocardial infarction at the ultrastructural level.
• To determine if TTC can identify irreversible ischemic injury in heart tissue prior to overt necrosis.

Main Methods:

• Eight dogs underwent induced coronary artery occlusion for six hours.
• Excised heart slices were incubated with TTC, and tissue samples were analyzed via electron microscopy.
• Samples were taken from both TTC-stained and unstained areas, near and remote from the induced infarct.

Main Results:

• All dogs exhibited distinct unstained (infarcted) and stained (viable) regions.
• Ultrastructural analysis of unstained tissue revealed significant cellular damage, including mitochondrial abnormalities and edema.
• TTC-stained tissue showed minimal changes, indicating reversible injury or healthy cells.

Conclusions:

• Triphenyltetrazolium chloride (TTC) is a dependable stain for identifying myocardial cells with ultrastructural evidence of irreversible ischemic injury.
• TTC accurately demarcates infarcted areas in the early stages of myocardial ischemia, even before histologic necrosis is apparent.