Force Reversal During Systolic–Diastolic Transition Provides Incremental Prognostic Value over LVEF for Heart Failure After STEMI

<b>Background:</b> Left ventricular hemodynamic forces (LV HDFs) are altered in myocardial dysfunction. While infarct location and size influence post-ST-segment elevation myocardial infarction (STEMI) remodeling, their specific effects on HDFs remain unclear. This study investigated how infarct location and size impact left ventricular HDFs and assessed HDFs' prognostic value for predicting subsequent heart failure (HF) in STEMI patients. <b>Methods:</b> In this retrospective study, 275 STEMI patients underwent cardiac magnetic resonance (CMR) 3-7 days after primary percutaneous coronary intervention. HDFs were derived from routine CMR cine images. Patients were stratified by infarct location (anterior vs. non-anterior) and median infarct size (IS). Key parameters-apical-basal (A-B) and lateral-septal (L-S) forces, their ratio, force direction angle (φ), and force reversal during systolic-diastolic transition-were compared. The primary endpoint was new-onset congestive HF during follow-up. <b>Results:</b> Compared to non-anterior STEMI, anterior STEMI showed significantly impaired A-B and L-S HDFs throughout the cardiac cycle (all <i>p</i> < 0.05) and was independently associated with force reversal (OR 2.31, 95% CI: 1.05-5.07). Larger IS correlated with reduced A-B HDFs and altered force distribution (increased L-S/A-B ratio, decreased φ). Force reversal predicted HF (HR: 2.10, 95% CI: 1.22-3.62) and provided incremental prognostic value beyond left ventricular ejection fraction (LVEF) alone (C-statistic: LVEF 0.680 vs. LVEF + force reversal 0.770, <i>p</i> = 0.034). <b>Conclusions:</b> Anterior infarction causes global HDF impairment and force reversal, while larger IS primarily reduces longitudinal forces and disrupts force distribution. Force reversal predicts subsequent HF and enhances prognostic value beyond LVEF.