J wave syndromes as a cause of malignant cardiac arrhythmias.

The J wave syndromes, including the Brugada (BrS) and early repolarization (ERS) syndromes, are characterized by the manifestation of prominent J waves in the electrocardiogram appearing as an ST segment elevation and the development of life-threatening cardiac arrhythmias. BrS and ERS differ with respect to the magnitude and lead location of abnormal J waves and are thought to represent a continuous spectrum of phenotypic expression termed J wave syndromes. Despite over 25 years of intensive research, risk stratification and the approach to therapy of these two inherited cardiac arrhythmia syndromes are still rapidly evolving. Our objective in this review is to provide an integrated synopsis of the clinical characteristics, risk stratifiers, as well as the molecular, ionic, cellular, and genetic mechanisms underlying these two syndromes that have captured the interest and attention of the cardiology community over the past two decades.