Depolarization versus repolarization abnormality underlying inferolateral J-wave syndromes: New concepts in sudden cardiac death with apparently normal hearts

Michel Haïssaguerre, Koonlawee Nademanee, Méleze Hocini, MD, Ghassen Cheniti, MD, Josselin Duchateau, Antonio Frontera, Frédéric Sacher, Nicolas Derval, Arnaud Denis, Thomas Pambrun, Rémi Dubois, Pierre Jaïs, David Benoist, Richard D. Walton, Akihiko Nogami, Ruben Coronel, Mark Potse, Olivier Bernus

Heart Rhythm, 16 (5) (May 2019): 781-790.

ABSTRACT
Early repolarization indicates a distinct electrocardiographic phenotype affecting the junction between the QRS complex and the ST segment in inferolateral leads (inferolateral J-wave syndromes). It has been considered a benign electrocardiographic variant for decades, but recent clinical studies have demonstrated its arrhythmogenicity in a small subset, supported by experimental studies showing transmural dispersion of repolarization. Here we review the current knowledge and the issues of risk stratification that limit clinical management. In addition, we report on new mapping data of patients refractory to pharmacologic treatment using high-density electrogram mapping at the time of inscription of J wave. These data demonstrate that distinct substrates, delayed depolarization, and abnormal early repolarization underlie inferolateral J-wave syndromes, with significant implications. Finally, based on these data, we propose a new simplified mechanistic classification of sudden cardiac deaths without apparent structural heart disease.