Macroscopic enzyme histochemistry in myocardial infarction: use of coenzyme, cyanide, and phenazine methosulphate.

Transversely sectioned human heart slices, obtained at necropsy from normal subjects and from cases of recent myocardial infarction, were stained with the nitroblue tetrazolium (NBT) dehydrogenase macroreaction for the gross identification of recent myocardial infarction. The addition of nicotinamide adenine dinucleotide (NAD) to the incubating medium greatly improved the sensitivity of the method, while addition of cyanide caused just a modest improvement. Addition of the electron transfer mediator phenazine methosulphate (PMS) resulted in false non-selective staining and obscured areas of recent myocardial damage.