SENSITIVITY AND SPECIFICITY OF TRIPHENYL TETRAZOLIUM CHLORIDE IN THE CROSS DIAGNOSIS OF ACUTE MYOCARDIAL INFARCTS

Objective.-Myocardial infarction is the most common cause of sudden de ath in the United States. However,the identification of early myocardi al infarcts at necropsy is frequently difficult, since unequivocal gro ss changes of infarcts do not become apparent for 24 to 48 hours follo wing myocardial ischemic injury. The use of dyes, such as nitroblue te trazolium and 2,3,5 triphenyl tetrazolium chloride (TTC), that identif y the dehydrogenase-deficient infarcted myocardium has been shown, lar gely by animal studies, to be very helpful in the macroscopic diagnosi s of such cases. Such animal studies could not be directly extrapolate d to human autopsy studies, however, because of the assumption that au tolysis may invalidate the histochemical assessment of myocardial enzy matic changes after death. This study was carried out to evaluate the sensitivity and specificity of TTC in the gross diagnosis of acute myo cardial infarction in the human population. Design.-The TTC stain reac tions were correlated with histologic findings in the hearts of 638 co nsecutive adult autopsies. Results.-Of the 638 hearts examined by TTC, 174 hearts stained positive for acute infarction; histology confirmed myocardial infarction in 140 hearts. Histologic examination revealed acute infarcts in 41 of the remaining 464 cases that had stained negat ively with TTC. The use of TTC in the macroscopic diagnosis of acute m yocardial infarcts in the human population was found to have a diagnos tic sensitivity of 77.4% and a specificity of 92.6%. The predictive va lue of a positive test was 80.5%, and that of a negative test was 91.2 %; Conclusions.-The overall diagnostic efficiency of the TTC test tie, number of patients correctly identified) was 88%. These results show that the TTC test is a reliable, sensitive, and specific adjunct in th e examination of the human heart at necropsy.