B-po01-103 immediate change in systolic stretch fraction predicts responsiveness to cardiac resynchronization therapy in patients with congenital heart disease

Anatomic heterogeneity and a lack of standardized functional assessment limit current predictive modeling for CRT responsiveness and efficacy. Echocardiographic electromechanical-discoordination indices provide a novel assessment platform for myocardial deformation with defined advantages over traditional measures of mechanical dyssynchrony. The purpose of this study was to evaluate electromechanical-discoordination indices (systolic stretch fraction (SSF) and diastolic relaxation fraction (DRF)) before and after CRT in patients with CHD-related heart failure. Functional echocardiography was analyzed pre- and post-CRT (n=12) for defined markers of mechanical dyssynchrony: time-to-peak (TTP) deviation, global circumferential strain (GCS), SSF and DRF. SSF and DRF were derived from the relative proportion of myocardial contraction to relaxation in systole and diastole, respectively, using a myocardial-specific strain rate curve. Five patients were classified as CRT responders and seven as non-responders. While there were no differences in immediate pre- vs post- echocardiographic markers for the entire cohort (Fig A), patients classified as responders had a significant immediate reduction in SSF (P=0.025) (Fig B). Change in echocardiographic markers when comparing responder status revealed no change in TTP (P=0.268), GCS (P=0.267), and DRF (P=0.531). Patients who respond to CRT therapy show immediate improvement in SSF. Analyzing the proportion of myocardial contraction to relaxation during systole might serve as a potential marker of peri-operative optimization and CRT responsiveness.