Abstract 4143691: Prediction of extent of reverse remodeling and outcome after cardiac resynchronization therapy using a strain-based classification of dyssynchrony

Introduction: Echocardiography-derived septal strain patterns can serve as indicators of the progressive left ventricular (LV) remodeling caused by left bundle branch block (LBBB)-induced dyssynchrony. Research question: What is the prognostic value of these strain patterns in predicting volumetric response and clinical outcome in patients undergoing cardiac resynchronization therapy (CRT)? Methods: In this prospective multicenter study, CRT candidates from 5 centres received pre-implantation echocardiographic assessments with speckle-tracking strain analysis. Dyssynchrony was quantified through the analysis of septal strain curves, categorizing patients into 5 distinct strain patterns, denoted as Stage-0 through Stage-4 (Fig. 1). Extent of reverse remodeling was determined at 1 year. The pre-defined endpoint was death from any cause. Results: A total of 267 patients were included (66±11 years, 69% males, 90% LBBB, LV ejection fraction [EF] 30±7%). CRT yielded a progressive reverse remodeling: minimal in Stage-0 patients (ΔLV end-systolic volume (ESV) -9±21ml; ΔLVEF +4±8%) and substantial in Stage-4 patients (ΔLV ESV -85±54ml; ΔLVEF +20±9%) (ANOVA p<0.001 for both) (Fig. 2). Median follow-up was 49 months. Stage-0 patients showed the least favorable outcome (log rank p=0.002), while subsequent stages exhibited progressively more favorable outcome (log rank p=0.045) (Fig. 3). The occurrence of death decreased incrementally according to the strain stages, with corresponding hazard ratios of Stage-1 through -4: 0.61 (95% CI 0.25-1.50), 0.26 (95% CI 0.10-0.68), 0.29 (95% CI 0.11-0.77), and 0.13 (95% CI 0.04-0.51) compared to Stage-0 (all p<0.001). After adjusting for baseline LVEF, ischemic heart disease, and the presence of an ICD, strain staging maintained a significant association with a reduced risk of adverse outcomes (hazard ratio 0.69 (95% CI 0.51-0.92), p<0.001). Conclusions: Septal strain patterns show a clear association with the extent of reverse remodeling and outcome in CRT-treated patients. The proposed strain staging classification offers valuable insights into the pathophysiology of LBBB-induced LV remodelling and may assist in the identification of candidates who stand to gain the most from CRT implantation.