Inclusion Criteria:  Anterior myocardial infarct (anterior myocardial infarct is defined as persistent chest pain for 30 mins at least, with ST-segment elevation of at least 0.2 mV in two or more contiguous precordial leads) within 12 hours after onsets of symptom; Left anterior descending (LAD) as culprit vessel, with TIMI 0-1 grade.  Exclusion Criteria:  significant valvular disease; cardiomyopathy; l left bundle branch block; atrial fibrillation; previous myocardial infarction (MI); history of cardiac surgery; pacemaker implantation.