Synergistic Value of Combined Electrical, Structural, and Functional Response Metrics in the Prediction of Long-Term Event-Free Survival After Cardiac Resynchronization Therapy

Background:Cardiac resynchronization therapy (CRT) is a cornerstone in the management of patients with heart failure with reduced ejection fraction (HFrEF) and electrical dyssynchrony. This study aimed to identify clinical, electrocardiographic (ECG), biomarker, echocardiographic, and cardiac magnetic resonance (CMR) imaging parameters predictive of 2-year all-cause mortality and hospitalization following CRT implantation.Methods:We retrospectively analyzed data from patients undergoing CRT. Baseline characteristics and 6–12-month follow-up data, including biomarkers, ECG parameters, echocardiographic measures, and CMR parameters, were assessed. Univariate and multivariate regression analyses were performed to identify predictors of 2-year event-free survival, defined as freedom from all-cause mortality or hospitalization.Results:At baseline, higher N-terminal pro-B-type natriuretic peptide (NT-proBNP) and creatinine levels, impaired right ventricular ejection fraction (RVEF), increased right ventricular end-systolic volume (RVESV), and reduced left ventricular global longitudinal strain (LV GLS) were significantly associated with adverse outcomes. At follow-up, event-free patients had lower NT-proBNP levels, higher left ventricular ejection fraction (LVEF), and lower left ventricular end-systolic volume (LVESV). Response rates for QRS complex (QRS) shortening (≥20 ms), LVEF improvement (≥10% absolute increase), and LVESV reduction (≥15%) were significantly higher in the event-free group. Univariate predictors of 2-year event-free survival included baseline RVEF (odds ratio (OR) 0.958; p = 0.015), baseline LV GLS (OR 1.256; p = 0.047), and follow-up LVEF (OR 0.932; p = 0.006). In contrast, higher follow-up Right Ventricular End-systolic Volume Indexed (RVESVi) (OR 1.013; p = 0.048) was associated with increased risk. A multivariate model incorporating QRS duration shortening (≥20 ms), LVESV reduction (≥15%), and LVEF improvement (≥10%) was highly predictive of 2-year event-free survival (p = 0.006; area under the curve (AUC) 0.835, accuracy 84%, specificity 97.5%, sensitivity 30%), with a QRS duration response ≥20 ms emerging as the strongest independent predictor (adjusted OR 0.111; p = 0.02).Conclusion:Combined improvement in QRS duration, LVESV, and LVEF after CRT implantation is a strong predictor of 2-year event-free survival. These findings support a comprehensive, multiparameter approach to evaluating CRT efficacy and guiding clinical management.