Cine dyscontractility index: A novel marker of mechanical dyssynchrony that predicts response to cardiac resynchronization therapy

Purpose To investigate whether magnetic resonance imaging (MRI) cine‐derived dyssynchrony indices provide additional information compared to conventional tagged MRI (tMRI) acquisitions in heart failure patients undergoing cardiac resynchronization therapy (CRT). Materials and Methods Patients scheduled for CRT (n = 52) underwent preprocedure MRI including cine and tMRI acquisitions. Segmental strain curves were calculated for both cine and tMRI to produce a range of standard indices for direct comparison between modalities. We also proposed and evaluated a novel index of “dyscontractility,” which detects the presence of focal areas with paradoxically positive circumferential strain. Results Across conventional strain indices, there was only moderate‐to‐poor (R = 0.3–0.6) correlation between modalities; eight cine‐derived indices showed statistically significant (P < 0.05) relations to CRT outcome compared to just two tMRI‐based counterparts. The novel dyscontractility index calculated on basal slice cine images (cine dyscontractility index, “CDI”) was the single best predictor of clinical response to CRT (area under the curve AUC = 0.81, P < 0.001). While poorly correlated to its tMRI counterpart (R = 0.33), CDI performed significantly better in predicting response to CRT (P < 0.005), and was also numerically better than all other tMRI indices (AUC 0.53–0.76, all P for AUC comparisons