Brugada syndrome is characterized by a ST shift on the surface ECG, and a specific morphology of the Twave. This ECG abnormality is called a type 1-ECG, and is variable in time. Patients presenting a Brugada syndrome are exposed to sudden cardiac death, although it's difficult to predict patients at high risk. It is suspected that the type 1-ECG burden might be correlated to the ventricular fibrillation risk of these patients, but there is no mean to record the ECG over a long period of time.

The objective of the study is to evaluate the correlation between ST elevation on the electrocardiogram (ECG) and ST shift on the intracardiac electrograms (EGM) recorded with the AnalyST ICD, to assess the ability of the device to detect the type 1-ECG. Patients enrolled in the study are patients already implanted with a defibrillator for their Brugada syndrome. During an Ajmalin test, which unmasks the type 1-ECG, both intracardiac EGM and surface ECG will be compared to assess the detection of the typical ST-shift by the ICD.

To evaluate the correlation between ST elevation on the ECG and ST shift on the intracardiac EGM recorded with the AnalyST ICD, patients enrolled will have to be already diagnosed as presenting the Brugada Syndrome. They will undergo an ajmaline test, to unmask the type 1-ECG, characteristic from the Brugada syndrome.During the test, both surface ECG and intracardiac signal will be continuously recorded; then the signals will be compared in terms of amplitude of the ST shift, duration of the shift, and recovery period.

Inclusion Criteria:

• Patients with Brugada syndrome and previous positive Ajmalin test