Increases in repolarization heterogeneity predict left ventricular systolic dysfunction and response to cardiac resynchronization therapy in patients with left bundle branch block

Introduction This study aimed to investigate the association between T‐wave morphology and impaired left ventricular ejection fraction (LVEF) in patients with complete left bundle branch block (cLBBB), and the predictive value of T‐wave morphology for response to cardiac resynchronization therapy (CRT). Methods and Results We enrolled 189 patients with cLBBB on electrocardiogram performed between January 2007 and December 2011 who underwent standard echocardiography. Repolarization parameters, including the QRS‐to‐T angle (TCRT), T‐wave morphology dispersion (TMD), T‐wave loop area (PL), and T‐wave residuum (TWR), were reconstructed from digital standard 12‐lead electrocardiograms by T‐wave morphology analysis. CRT response was defined as ≥15% reduction in left ventricular end‐systolic volume at 12 months after CRT implantation. The clinical outcome endpoint was a composite of heart failure hospitalization, heart transplantation, or death during follow up (mean, 5.8 years). On logistic regression, a higher heart rate, longer QRS duration, increased TMD, and larger TWR were all independently associated with LVEF