Site-specific arrhythmogenesis in patients with Brugada syndrome.
BACKGROUND
It has been believed that electrophysiologic abnormality of the epicardial region of the right ventricular free wall may play an important role in arrhythmogenesis of phase 2 reentry in Brugada syndrome, but clinical evidence of the occurrence of ventricular arrhythmias at the right ventricular free wall has not been evaluated. In this study, we evaluated the site-specific inducibility of ventricular fibrillation (VF) and the origin of spontaneous premature ventricular contractions (PVCs) in patients with Brugada syndrome.


RESULTS
Forty-five patients with Brugada-type ECG were enrolled in this study. Spontaneous PVCs were recorded in 9 patients. Programmed electrical stimulation (PES) was performed at the right ventricular apex (RVA), the free wall and septal region of the right ventricular outflow tract (RVOT), and the left ventricle (LV). The inducibility of PVT/VF was evaluated at each ventricular site, and the origin of PVC was determined by pace mapping. Sustained VF was induced in 17 patients. VF was induced in all 17 patients by PES at RVOT. Although PES at the septal region of the RVOT induced VF in only 5 patients (29%), PES at the free-wall region of the RVOT induced PVT/VF in 13 patients (76%). PES at RVA induced VF in only 2 patients (12%), and PES at LV failed to induce any arrhythmic events. Ventricular pace mapping showed that 64% of PVCs occurred at the free-wall region of the RVOT, 18% at the septal region of the RVOT, 9% at RVA, and 9% at LV.


CONCLUSIONS
VF in patients with Brugada syndrome frequently is induced at the free-wall region of the RVOT area. The origin of PVC appears to be related to the site of PVT/VF induction by PES.
Department of Cardiovascular Medicine, Okayama University Graduate School, Okayama, Japan. hmorita@cc.okayama-u.ac.jp
Hiroshi
H
Morita
Kengo
K
Fukushima-Kusano
Satoshi
S
Nagase
Shiho
S
Takenaka-Morita
Nobuhiro
N
Nishii
Mikio
M
Kakishita
Kazufumi
K
Nakamura
Tetsuro
T
Emori
Hiromi
H
Matsubara
Tohru
T
Ohe
D000328:Adult; D000368:Aged; D001145:Arrhythmias, Cardiac / Q000209:etiology* / Q000473:pathology; D016757:Death, Sudden, Cardiac / Q000473:pathology*; D004558:Electric Stimulation; D004562:Electrocardiography; D005260:Female; D006329:Heart Conduction System / Q000502:physiology; D006801:Humans; D008297:Male; D008875:Middle Aged; D012032:Refractory Period, Electrophysiological; D013577:Syndrome; D014693:Ventricular Fibrillation / Q000473:pathology*; D016277:Ventricular Function, Left; D016278:Ventricular Function, Right; D014694:Ventricular Outflow Obstruction / Q000503:physiopathology