Precision of automated QRS duration measurement in patients treated with cardiac resynchronization therapy

Purpose Shortening of the QRS duration (QRSd) is often used to guide device optimization and reprogramming in patients with cardiac resynchronization therapy (CRT). Detecting the small changes expected during reprogramming requires that the QRSd can be measured with high precision, but this has never been studied in patients with CRT. In this study, we wanted to assess the precision of automated QRSd measurement in patients treated with CRT using two commonly available electrocardiographs.