Because of some possible similarities between early repolarisation and this syndrome, and because some patients with the syndrome have been misdiagnosed as early repolarisation, a discussion of the similarities, differences and electrophysiologic mechanisms of these two syndromes is justified.

Early repolarisation is a frequent finding in healthy, usually sportive, young men. The Brugada syndrome also frequently affects active, sportive, and apparently healthy young men. During exercise, there is a normalization of the ST segment in both situations. Adrenergic stimulation with isoproterenol normalizes the ST segment in both syndromes, while beta-adrenergic blockade increases the ST segment elevation. Which are the differences between the two syndromes then? The first and very much important difference is that normal individuals with early repolarisation do not develop sudden death because of ventricular arrhythmias. There exist also electrocardiographic differences between the two syndromes, like the type and localization in the precordial leads of the ST segment elevation (picture 12).

Although the underlying cellular electrophysiologic mechanisms of early repolarisation are not completely clear, some electrophysiologic similarities between the two syndromes may exist. From a discussion with Dr. Antzelevitch, picture 13 was drawn to try to understand the differences between early repolarisation, long QT syndrome and Brugada syndrome, and why arrhythmias do not occur in the first situation but do occur in the other two.