Benign or malignant, early or delayed: the changing face of early repolarization

Abstract

Early repolarization (ER) has historically been considered a benign electrocardiogram (ECG) variant, and is seen more commonly in young males and individuals who undertake high levels of athletic activity and/or are of black ethnicity.1 It has recently, however, been proposed as a marker for an increased risk of sudden cardiac death (SCD). In particular, ER in the inferior ECG leads has been associated with idiopathic ventricular fibrillation and has been termed as the ER syndrome.2,3 Although ER is a common ECG finding, the syndrome is rare. Indeed in a general population study, middle-aged individuals with inferior ER only had a three-fold increased risk of SCD which was not apparent until 10 years after their initial diagnostic ECG.3 Until recently, there have been no risk stratifiers for asymptomatic subjects with ER and no primary prevention therapy. Much of this has been complicated by uncertainties over the definition of ER, how to measure it, and its actual causation. It has therefore been impossible to make recommendations based on this incidental ECG finding in an asymptomatic individual and this has become a concern for the cardiology community. ### Historical perspectives and definitions The definition of ER has evolved. It was defined by Wasserburger1 in 1961 as elevated take-off of the ST-segment at the end of the QRS (the J junction) with downward concavity of the ST-segment and symmetrical T-waves seen particularly in the lateral ECG leads ( Figure 1C ). In 2008, it …