Effect of PR interval prolongation on long-term outcomes in patients with left bundle branch block vs non-left bundle branch block morphologies undergoing cardiac resynchronization therapy

PRp is an independent predictor of impaired long-term outcome after CRT among patients with LBBB but not in non-LBBB patients. Notably, among LBBB patients, PRp is a more important predictor than QRSd in assessing long-term outcomes.