Beyond Remodeling: Four Structural-Functional Recovery Patterns as a Framework for Interpreting Ventricular Recovery...

Background/Objectives: Ventricular recovery after ST-segment elevation myocardial infarction (STEMI) is commonly assessed using either structural (volumetric) or functional (ejection-fraction) criteria, although these may capture different aspects of recovery. We examined whether their cross-classification identifies distinct recovery patterns and whether myocardial mechanics and left atrial function provide additional information. Methods: We prospectively followed 101 patients with first STEMI and single-vessel coronary artery disease treated with PCI. Echocardiography was performed 12-24 h after reperfusion and at 12 ± 2 months. Structural recovery (≥15% reduction in 3D LV end-systolic volume) and functional recovery (≥5-point absolute LVEF increase) were cross-classified into four recovery patterns. Results: Among 53 patients with complete paired measurements, 10 (18.9%) showed concordant recovery, 7 (13.2%) isolated structural recovery, 9 (17.0%) isolated functional recovery, and 27 (50.9%) no recovery; 30.2% therefore showed discordant recovery. The no-recovery group was heterogeneous, including both volumetric deterioration and stable or improving volumes below the recovery threshold. Continuous changes in 3D-ESV and LVEF were only moderately correlated (ρ = 0.353, p = 0.0095), and discordance persisted in sensitivity analyses. Myocardial mechanics and LASR did not differentiate recovery patterns, but several of these baseline markers showed exploratory associations with clinical outcomes after false-discovery-rate correction. Conclusions: Structural and functional recovery after STEMI are complementary rather than interchangeable, and this discordance persisted across extensive sensitivity analyses; however, assignment of individual patients to specific recovery categories remained sensitive to the chosen thresholds and LVEF measurement method. Myocardial mechanics and LASR may provide additional information about clinical expression.