The usage of ATR-FTIR spectroscopy combined with chemometrics in postmortem diagnosis of acute myocardial infarction

Myocardial infarction (MI) represents a leading cause of sudden death; however, the identification of acute MI in postmortem examinations remains challenging due to the lack of specific early morphological markers. This study explores the utility of attenuated total reflectance-Fourier transform infrared (ATR-FTIR) spectroscopy, in combination with chemometric analysis, for the postmortem diagnosis of MI. A rat model of MI was employed, and the expression levels and protein concentrations of JUNB and myoglobin (MYO) were quantified to corroborate the spectral findings. ATR-FTIR analysis revealed significant alterations in collagen and nucleic acid content between the control and MI groups, particularly during the early postmortem intervals. Principal component analysis (PCA) and hierarchical cluster analysis (HCA) successfully differentiated between groups, achieving 100 % sensitivity and specificity, and 97 % classification accuracy through PCA-based linear discriminant analysis (LDA). Support vector machine (SVM) classification further confirmed these findings. Notably, spectral changes at 3285, 3016, 2920, 1338, 1236, and 974 cm⁻¹ exhibited strong correlations with JUNB and MYO gene and protein levels. This integrative approach demonstrates that ATR-FTIR spectroscopy, combined with multivariate analysis and molecular markers, offers a rapid, non-destructive, and highly accurate method for the early postmortem diagnosis of acute MI, highlighting its potential for forensic and clinical applications.