In patients with ST-segment elevation myocardial infarction (STEMI), it is unclear if combined assessment of left ventricular end-diastolic pressure (LVEDP) and left ventricular ejection fraction (LVEF) improves prediction of major adverse cardiac events (MACE). We analyzed data from 266 STEMI patients who underwent successful percutaneous coronary intervention and subsequent left ventriculography (LVG). Patients were divided into 4 groups, as follows: Group 1, LVEDP < 21 mmHg and LVEF ≥ 55%; Group 2, LVEDP < 21 mmHg and LVEF < 55%; Group 3, LVEDP ≥ 21 mmHg and LVEF ≥ 55%; and Group 4, LVEDP ≥ 21 mmHg and LVEF < 55%. Multivariate Cox proportional hazards analysis was used to determine if LVEDP and LVEF were associated with MACE (including cardiac death, non-fatal myocardial infarction, and heart failure requiring hospitalization). Change in LV parameters was assessed in the subset of 183 patients who underwent serial LVG (mean interval 6.3 ± 1.6 months). During a mean follow-up of 43 ± 31 months, 29 patients (10.9%) had a MACE. As compared to Group 1, MACE risk was significantly higher in Group 3 [hazard ratio (HR) 3.26; 95% confidence interval (CI) 1.05–10.0] and Group 4 (HR 3.99; 95% CI 1.44–11.0), but not in Group 2 (HR 0.46, 95% CI 0.54–3.96). In sub-analyses, LV end-systolic volume index after PCI was significantly higher in Group 4 than in the other groups and remained higher during follow-up. Combined LVEDP/LVEF assessment was useful in predicting MACE after successful PCI for STEMI patients and could facilitate risk stratification, as it predicts LV remodeling.