Okafor O, Zegard A, van Dam P, et al. - Researchers undertook this retrospective analysis to investigate if clinical outcomes post-cardiac resynchronization therapy (CRT) could be predicted by pre- and postimplantation QRS area (QRS_area). This study included 380 patients of age 72.0 ± 12.4 years, including 68.7% male, who were undergoing CRT over 7.7 years (median follow-up: 3.8 years [interquartile range 2.3–5.3]). Pre- and postimplantation vectorcardiography was used to derive QRS_area, which was evaluated in association with the primary end point of cardiac mortality following CRT with or without defibrillation. Total mortality, total mortality or heart failure hospitalization, total mortality or major adverse cardiac events, and the arrhythmic end point of sudden cardiac death or ventricular arrhythmias with or without a shock were also assessed. Findings revealed the superiority of preimplantation QRS_area (derived from vectorcardiography) over QRS duration (QRSd) and QRS morphology in predicting cardiac mortality post-CRT. The best results, including the arrhythmic end point, were reported in relation to a postimplant reduction in both QRS_area and QRSd.