J waves and early repolarization: Do not confuse me with the facts!

Abstract

s Cardiac electrophysiologists like to argue. Driven by intellectual curiosity and scientific skepticism, they will argue just about anything, from purely theoretical issues such as the electrophysiologic mechanism behind the U wave to matters of utmost clinical importance such as the best treatment for Brugada syndrome. Add to this the ottest debate nowadays: What do the “J waves of early epolarization” represent? Early repolarization and J waves are common electrocardiographic (ECG) phenomena observed in young, healthy individuals, predominantly if they are males, athletic, and of African American descent. However, this is as far as the general agreement in the electrophysiology community goes. Experts differ with regard to terminology, etiolgy, prevalence, clinical significance, and long-term mplications of the same ECG features. This controersy pertains in part to terminology. Although the term early repolarization” has been used to denote the combiation of J waves and ST-segment elevation, recent evience suggests that these 2 ECG features should be considred individually. As explained elsewhere, previous studies concluding that early repolarization is “benign” focused mainly on ST-segment elevation whereas more recent evidence suggests that the presence of tall J waves without ST-segment elevation may be particularly arrhythmogenic. The importance of “terminology” is highlighted by a recent series showing that the prevalence of J-point elevation varies from 2% to 30% in the same cohort depending on the definition used. Having said that, more fundamental controversies about the essence of early repolarization exist between authorities in clinical electrocardiography and basic science. The former argue that the “normal J-point elevation” and the “pathologic J wave” are 2 clearly distinct terms, not to be used interchangeably. In contrast, experimental data favor a “gradual spectrum” explanation. According to tissueased experiments, small gradients in ventricular repolarzation (ie, small differences in action potential duration in