Nam MCY, Meneses AL, Byrne CD, et al. - In this study, four experiments were performed to ascertain how insulin infusion duration, dose, and presence of insulin resistance influence myocardial blood flow reserve (MBFR) response and the impact of an insulin-dextrose infusion given immediately following revascularization of ST-segment elevation myocardial infarction (STEMI) on myocardial perfusion. Researchers applied myocardial contrast echocardiography to ascertain MBFR. Experiment 1 (insulin duration) included 12 participants who received an insulin-dextrose or saline infusion for 120 minutes. MBFR was assessed at four time intervals during infusion. Experiment 2 (insulin dose) included 22 participants who received one of three insulin doses (0.5, 1.5, 3.0 mU/kg/minute) for 60 minutes. Baseline and 60-minute MBFRs were ascertained. Experiment 3 (insulin resistance) included five metabolic syndrome and six T2DM individuals who received 1.5 mU/kg/minute of insulin-dextrose for 60 minutes. Baseline and 60-minute MBFRs were ascertained. Experiment 4 (STEMI): following revascularization for STEMI, 20 patients were assigned randomly to receive either 1.5 mU/kg/minute insulin-dextrose infusion for 120 minutes or standard care. To evaluate percentage contrast defect length, myocardial contrast echocardiography was conducted at four time intervals. The study found that presence of T2DM, insulin infusion duration, and dose are important determinants of the MBFR response to HE. Insulin-dextrose decreases perfusion defect size at one hour when given immediately following revascularization for STEMI. Hyperinsulinemic euglycemia may enhance MBF following ischemia, but future research is needed to verify this.