PO-02-021 DIRECTION OF REPOLARIZATION IN BASELINE ECG IS PREDICTIVE OF RESPONSE TO CARDIAC RESYNCHRONIZATION THERAPY

Abstract

Cardiac resynchronization therapy (CRT) is a cornerstone of treatment for advanced heart failure, but not all patients derive equal benefit from this intervention. Current approaches of using electrocardiographic and echocardiographic parameters to identify likely CRT responders demonstrate poor predictive ability. We seek to identify electrocardiographic parameters that can improve prediction of benefit with CRT This was a retrospective analysis of patients who underwent CRT-D placement at University of Pittsburgh Medical Center from 2014-2020. Patients were excluded if pre-implantation EKG or pre- and post-implantation echocardiograms were not available. Each patient’s immediate pre-implantation ECG was processed using the CineECG software (EKG Excellence) to obtain the mean temporospatial isochrone of ventricular activation. 192 features quantifying the activation and recovery pathways were computed for each patient. Response to CRT was defined as an improvement in ejection fraction (EF) of 5% on follow-up transthoracic echocardiogram 3-12 months after CRT implantation. Forward sequential feature selection was used to identify the features of highest importance based on negative logistic loss. 276 patients were included in this analysis (36% female, mean age 69 years, mean pre-procedural EF 27%). The 10 most important CineECG features were identified. When these features were used in a multivariate logistic regression, three features were independently predictive of CRT response: left bundle branch block (LBBB); leftward direction of late repolarization potentials (i.e., Tpeak - Tend rotated toward LV in the horizontal plane); and location of center-of-mass of terminal cardiac activation. Compared to CRT responders (n=169, 62%), non-responders were more likely to have abnormal direction of late repolarization potentials in both LBBB group (-0.34±0.30 vs. -0.45±0.30 vs, p=0.027) and RBBB group (0.25±0.51 vs. 0.61±0.27, p=0.031). In the latter group, direction of later repolarization potentials correlated with magnitude of change in post-procedural EF (r=0.23, p=0.016). Our findings confirm that the presence of LBBB is predictive of response to CRT. In addition, our data suggests that in patients with RBBB, a more leftward direction of late repolarization potentials is independently predictive of CRT response. Further studies into repolarization dynamics as a predictor of CRT response in RBBB are warranted.