Haissaguerre syndrome: The gray area still exists

The term early repolarization (ER) is defined electrocardiographically by either a sharp well-defined positive deflection or notch immediately following a positive QRS complex at the onset of the ST-segment, or slurring at the terminal part of the QRS complex. This pattern is frequently observed in the general population. For decades, ER was regarded as a benign electrocardiographic variant. However, in 2008, Haïssaguerre et al described a strong relationship between J-waves and many different forms of ventricular arrhythmias in the absence of known heart disease. It seems likely that ER results from a net increase in outward current caused by a loss of inward-channel function or a gain in outward-channel function. It remains unclear whether these mutations are more functionally important in the epicardium, or whether they simply exaggerate the magnitude of preexisting epicardial-endocardial differences by increasing overall net outward current flow. This review will discuss the underlying mechanisms, genetic basis, risk stratification and management.