Egbe AC, et al. - In the current study, researchers sought to validate findings of a recent study demonstrating QRS fragmentation (QRS-f) as predictive of mortality in patients with tetralogy of Fallot (TOF). Reviewing the Mayo Adult Congenital Heart Disease database from 1990–2017, they identified 465 patients (age 37±14 years) with TOF who had ECG. Among these, 161 (35%) displayed QRS-f: mild (n=43, 9%), moderate (n=77, 17%), and severe (n=41, 9%). The severity of QRS-f was identified to be an independent predictor of all-cause mortality after adjustment for other ECG parameters, patient demographics, and atrial and ventricular arrhythmia