Regional patterns of activation during induced ventricular fibrillation in Brugada Syndrome

FUNDING ACKNOWLEDGEMENTS: Type of funding sources: None. INTRODUCTION: The activation pattern of induced ventricular fibrillation (VF) in Brugada Syndrome (BS) is not well known. OBJECTIVES: The aim is to establish a hypothesis about temporal activation in the right ventricle (RV) during induced VF in BS patients. METHODS: We examined the sequence of electrical activation in RV during induced VF by programmed stimulation (PS) in 8 patients diagnosed with BS. The 12 ECG leads were analyzed and the electrograms (EGMs) were recorded from a quadripolar catheter placed in the RV apex or in the right ventricular outflow tract (RVOT), from which ventricular fibrillation was induced. RESULTS: ECG recordings and EGMs of VF were analyzed in 8 patients diagnosed with BS. VF was induced from the RV apex and the RVOT in 6 and 2 patients respectively. From the onset of induced VF to the appearance of sinusoidal waves, three activation areas were observed based on ECG morphology and the activation timing of the right ventricular EGM: apex, moderator band (MB), and RVOT. The first activated area coincided from where VF was induced. The second activated area was the MB in 6 patients. Following RV apex activation, a sinusoidal signal appeared in 2 patients with no activation area being distinguished. Activation was from the MB to RVOT and toward the RV apex in 3 and 2 patients respectively. CONCLUSION: In ventricular fibrillation induced in Brugada Syndrome, the activation pattern is sequential from RVOT to RV apex and vice versa through the moderator band. [Figure: see text] [Figure: see text]