Type 2 diabetes mellitus is a well-established risk factor for coronary heart disease and atherosclerotic change in the coronary artery develops subclinically in a state of impaired glucose tolerance (IGT). Recently postprandial hyperglycemia as a feature of impaired glucose tolerance is recognized as a significant risk factor for coronary heart disease. So we designed a prospective randomized multi-center trial named Assessment of an α-glucosidase-inhibitor to Block Cardiac Events in Patients With Myocardial Infarction and IGT (ABC study) to evaluate whether an α-Glucosidase Inhibitor, a drug for the suppression of postprandial hyperglycemia, could reduce the recurrence of myocardial infarction in patients with IGT and old myocardial infarction.