OBJECTIVES: We studied the influence of abnormal glucose metabolism on left ventricular (LV) function and prognosis in 203 patients with acute myocardial infarction. BACKGROUND: Abnormal glucose metabolism is associated with increased mortality after acute myocardial infarction. This appears to be particularly attributable to an increased incidence of post-infarction congestive heart failure. A relationship between glucose metabolism and LV function could potentially explain this excess mortality. METHODS: In patients without known diabetes, glucose metabolism was determined using an oral glucose tolerance test before discharge. LV function was assessed using echocardiographic measurements (LV end-diastolic volume, LV end-systolic volume, LV ejection fraction, restrictive diastolic filling pattern, early transmitral flow velocity to early diastolic mitral annular velocity ratio [E/e'], and left atrial volume index) and by measuring plasma N-terminal pro-B-type natriuretic peptide levels. RESULTS: After adjustment for age and gender, a linear relationship between the degree of abnormal glucose metabolism was observed for each marker of LV dysfunction (p(trend) < 0.05) with the exception of left atrial volume index (p = 0.10). During a median follow-up of 21 months, 32 patients died, and 39 patients met the secondary end point of death or hospitalization for heart failure. After adjustment for differences in LV function, as well as other relevant characteristics, newly detected, as well as known diabetes were independent predictors of both all-cause mortality (hazard ratios [HR]: 4.2 [95% confidence interval (CI): 1.1 to 17.1] and HR: 5.7 [95% CI: 1.3 to 25.2], respectively), and the composite of death or hospitalization for heart failure (HR: 4.3 [95% CI: 1.2 to 15.6] and HR: 5.8 [95% CI: 1.5 to 22.3], respectively). Comparable nonsignificant trends were observed for patients with impaired glucose tolerance. CONCLUSIONS: Although perturbations in glucose metabolism were linearly associated with impairment of LV function in the early phase of acute myocardial infarction, this relationship alone did not explain the excess mortality in patients with newly detected or known diabetes.