At-risk and, especially, necrotic areas have a reduced concentration of NMR visible metabolites as compared to control tissue, total creatine (phosphorilated and unphosphorilated) being the single most important metabolite in the different discriminant models. Creatine concentration decreased from 18.28 +/- 0.84 micromols/g fresh weight in controls to 12.58 +/- 2.89 (P < 0.05) and 9.96 +/- 2.21 (P < 0.01) in at-risk and necrotic areas, respectively. Taurine and myo-inositol were also involved in the discriminant models. HR-MAS spectra also showed an increase in lipid signals at 0.9 and 1.28 ppm as markers of necrotic tissue. These results support the view that the analysis of in vivo (1)H MRS may have value in differentiating normal, at-risk and infarcted myocardium.