A vectorcardiographic evaluation of the consensus criteria for early repolarization

A 2015 consensus paper proposed a unified definition of the early repolarization (ER) pattern based upon quantification of end-QRS notches and slurs in the ECG. In this study we investigated the relationship between end-QRS concave “bite” segments in the vectorcardiogram (VCG) and the consensus ER pattern. We reviewed digital 12-lead ECG recordings from 1561 subjects in whom out-of-hospital cardiac arrest was later witnessed. ECGs were made available by the Copenhagen General Practitioners' Laboratory. The consensus criteria were used to quantify notches and slurs. ER manifestations were divided into 3 types: A) notches only B) notch and slur C) slurs only. An automatic algorithm developed by the authors were used to quantify bites in 3D. 85 of the 1561 subjects (5.4%) fulfilled the ECG consensus criteria for ER. End-QRS bites were present in 100 % of cases for types A and B and in 92 % of the cases for type C. Subjects with ER type A had the highest median bite amplitude with 79 μV, followed by 60 μV for type B and 36 μV for type C. Our investigation of end-QRS morphology in ER suggest the existence of a continuous transition from slurring to notching governed by the size of 3D VCG bites.