Interventricular conduction delay predicts CRT response: a comparative evaluation study between biventricular pacing and conduction system pacing
N Manetti, C Baiocchi, S Lunghetti, M Collantoni, L Spaccaterra, A Petrini, F Morrone, S Taddeucci, M Fineschi, F Landra, M Cameli, C Marallo, A Pagliaro, A SantoroAbstract
Background
Cardiac resynchronization therapy(CRT) improves outcomes in heart failure with electrical dyssynchrony, yet non-response remains common. Surface ECG markers such as QRS duration and morphology are imperfect predictors. Direct measurement of interventricular conduction delay (RV–LV) may better guide therapy and inform the choice between biventricular pacing (BiVp) and conduction system pacing (CSP).
Objectives
To compare CSP with BiVp in terms of reverse remodelling and to assess the predictive value of RV–LV delay.
Methods
Data were prospectively collected on 184 consecutive CRT recipients (127 BiVp,57 CSP) between January 2020 and December 2023. This study extends a previously reported cohort of 96 patients by including additional enrollment and new analyses stratified by interventricular delay. Patients were grouped as BiV with RV–LV <100 ms, BiV with RV–LV ≥100 ms, or CSP (bailout only). Co-primary endpoints were change in ejection fraction (ΔEF) and echocardiographic responder rate at 12 months.
Results
CSP was non-inferior to BiVp for ΔEF (mean difference –0.8 pp; lower one-sided 95% CI –3.38). Non-inferiority was not demonstrated for responder rate, despite a numerical advantage for CSP (77.2% vs 66.5%). Patients with BiVp ≥100 ms and those with CSP achieved greater ΔEF (~12%) and higher responder rates(~77%) than BiVp<100 ms (ΔEF 8%, responders 51%). On multivariable analysis, pacing modality and interventricular delay were independent predictors of response, while ischaemic aetiology was negative.
Conclusions
Restoration of physiological activation—either through BiV with adequate RV–LV delay or through CSP—emerges as the main determinant of reverse remodelling. Incorporating direct conduction measures into CRT decision-making may enhance patient selection beyond surface-ECG criteria.