Abstract 16450: The Impact of Left Ventricular versus Simultaneous Biventricular Pacing on Structural and Biochemical Reverse Remodeling in Patients With Heart Failure: Insights From the EvAluation of Resynchronization Therapy for Heart Failure (EARTH) Trial

Abstract

Introduction: Cardiac Resynchronization Therapy (CRT) with simultaneous biventricular pacing (BiVP) is recommended for patients with heart failure and wide QRS, however up to a third of patients do not respond. GREATER-EARTH has demonstrated similar benefits with BiVP or LV pacing (LVP). Herein, we evaluate the effects of these two CRT modes on cardiac remodeling, evaluated by echocardiography and circulating biomarkers. Methods: 121 patients (LVEF≤35% and QRS≥120ms) referred for defibrillator implantation were randomized to BiVP or LVP for consecutive 6-month periods with cross-over. The primary endpoint was the change in LV end-systolic volume (LVESV) between patients with BiVP vs LVP from baseline to 6 months. Secondary endpoints included changes in LVEF, mitral regurgitation, RV and diastolic function. Changes in levels of markers of cardiac remodeling were also compared. Results: Both CRT pacing modes led to remodeling benefits after 6-months of therapy: LVESV decreased from 162±57mL at baseline to 130±63mL with BiVP vs 130±60 mL with LVP (p=0.68 between CRTs), with a positive response (≥15% LVESV reduction) being observed in 49% of patients with BiVP and 33% of LVP, p=0.09. Similarly, RV remodeling (dimension and RV-MPI) was equally improved with both pacing strategies (p=0.69 and p=0.38 respectively, between CRTs). Interestingly, estimated systolic PAP (from 43±14 to 37±10 and 41±14, p=0.008), selected indices of LV diastolic function such as indexed LA volume (p=0.045) and diastolic dysfunction grade (p=0.019), as well as changes in MR grade (p=0.004) were significantly improved only with BiVP. In parallel, there was a non-statistically significant decrease in NT-proBNP, from 2559±3296 to 1554±2092 and 1630±1950 ng/L, with BiVP and LVP respectively (p=0.093) as well as a trend in decreasing PIIINP levels, from 8.3±3.0 to 7.5±2.7 and 7.6±2.3 with BiVP and LVP respectively, p=0.097. Conclusions: In this prospective, multicenter, randomized, double-blind study, both BiVP and LVP resulted in improvements in LV remodelling assessed by echocardiography, while more patients responded to BiVP. BiVP may be superior to LVP to improve multiple aspects of myocardial remodeling and should remain the preferred mode of CRT in patients with advanced HF.