Glucose-insulin-potassium infusions are beneficial in uncomplicated patients with acute myocardial infarction (AMI) but are of unproven efficacy in AMI with left ventricular (LV) dysfunction because of volume requirements associated with glucose infusion. Glucagon-like peptide-1 (GLP-1) is a naturally occurring incretin with both insulinotropic and insulinomimetic properties that stimulate glucose uptake without the requirements for concomitant glucose infusion. We investigated the safety and efficacy of a 72-hour infusion of GLP-1 (1.5 pmol/kg per minute) added to background therapy in 10 patients with AMI and LV ejection fraction (EF) <40% after successful primary angioplasty compared with 11 control patients. Echocardiograms were obtained after reperfusion and after the completion of the GLP-1 infusion. Baseline demographics and background therapy were similar, and both groups had severe LV dysfunction at baseline (LVEF=29+/-2%). GLP-1 significantly improved LVEF (from 29+/-2% to 39+/-2%, P<0.01), global wall motion score indexes (1.94+/-0.11-->1.63+/-0.09, P<0.01), and regional wall motion score indexes (2.53+/-0.08-->2.02+/-0.11, P<0.01) compared with control subjects. The benefits of GLP-1 were independent of AMI location or history of diabetes. GLP-1 was well tolerated, with only transient gastrointestinal effects. When added to standard therapy, GLP-1 infusion improved regional and global LV function in patients with AMI and severe systolic dysfunction after successful primary angioplasty.