This 2-center, 250-patient study evaluated the effect of normalization of QRS duration (QRSd) to left ventricular (LV) dimension on predicting survival following cardiac resynchronization device (CRT) implantation. The patients, who had heart failure with LV ejection fraction ≤35% and QRSd ≥120 ms, underwent cardiac MRI before implantation, and end-diastolic volumes were used for QRSd normalization. The primary endpoint was a combination of death, LV assist device or transplantation. The results suggested that 32% of patients experienced the primary endpoint. Unadjusted QRSd was not associated with CRT outcomes. Women demonstrated higher normalized QRSd than men (p=0.003), and had better survival (p=0.018).
Zweerink A, Friedman D, Klem I, et al. Circ Arrhyth Electrophysiol. 2018;doi: