GSTM1 and myocardial ischemia: One may speculate that inadequate oxygen carriers could impair cellular oxidative metabolism and exaggerate myocardial ischemia, thus promoting the extension of infarcted size (25, 26), as confirmed using SPECT imaging by Dutsch et al. (18) that larger myocardial infarctions were found in those with a Hb decrease of ≥3 g/dl during hospitalization.