Endocardial electrograms from the right ventricular outflow tract after induced ventricular fibrillation in patients with Brugada syndrome.
BACKGROUND
The pathogenesis of Brugada syndrome (BS) is reported to be phase 2 reentry resulting from shortening of the action potential duration at the epicardial site of the right ventricular outflow tract (RVOT). However, several reports have shown a high incidence of ventricular late potentials (LPs) and a high rate of induction of ventricular fibrillation (VF) by programmed ventricular stimulation (PVS) among patients with BS. The aim of this study was to investigate the role of slow conduction for the initiation of VF by PVS in these patients.


RESULTS
Endocardial mapping of the RVOT was conducted in 17 patients in whom VF was induced by PVS from the RV apex or RVOT; 11 patients had a positive LP. In 10 patients, RV mapping showed that low-amplitude fragmented and delayed potentials (DPs) were recorded at the RVOT below the pulmonary valve (PV) or between the PV and His bundle electrogram recording site. Electrograms recorded after PVS showed a high incidence of fractionated and disorganized DPs that lead to VF.


CONCLUSIONS
Slow conduction at the RVOT may contribute to the induction of VF by PVS. However, the role of slow conduction in spontaneous VF remains controversial.
Ohkubo
Kimie
K
Division of Cardiology, Department of Medicine, Nihon University School of Medicine, Tokyo, Japan.
Watanabe
Ichiro
I
Takagi
Yasuhiro
Y
Okumura
Yasuo
Y
Ashino
Sonoko
S
Kofune
Masayoshi
M
Kofune
Tatsuya
T
Shindo
Atsushi
A
Sugimura
Hidezou
H
Nakai
Toshiko
T
Kunimoto
Satoshi
S
Kasamaki
Yuji
Y
Saito
Satoshi
S
Hirayama
Atsushi
A
D000200:Action Potentials; D000328:Adult; D000368:Aged; D018780:Body Surface Potential Mapping; D053840:Brugada Syndrome / Q000209:etiology* / Q000503:physiopathology*; D004562:Electrocardiography; D006329:Heart Conduction System; D006801:Humans; D008297:Male; D008875:Middle Aged; D014693:Ventricular Fibrillation / Q000209:etiology / Q000503:physiopathology