Electrophysiologic characteristics and implications of induced ventricular fibrillation in symptomatic patients with Brugada syndrome.
OBJECTIVE
The study examined the electrocardiographic and electrophysiologic characteristics in relation to programmed ventricular stimulation (PVS)-induced ventricular fibrillation (VF), as well as the implications of PVS-induced VF on the recurrence of cardiac events in symptomatic Brugada syndrome.


BACKGROUND
Brugada syndrome is characterized by ST-segment elevation in the right precordial leads (V(1)-V(3)) and an episode of VF.


METHODS
Thirty-four symptomatic patients with Brugada syndrome (33 men and 1 woman; 44 +/- 12 years old) were classified into two groups according to the inducibility of VF with PVS: 22 patients with induced VF requiring direct cardioversion for termination (Induced VF group) and 12 patients without induced VF (Noninduced VF group).


RESULTS
The induced VF group showed a longer QRS duration, a higher incidence of right bundle branch block and late potentials detected on the signal-averaged electrocardiogram, longer His-ventricular intervals and a longer conduction time from the RVOT to the left ventricle at extrastimulation than those in the non-induced VF group. However, there was no significant difference in the recurrence of cardiac events (VF documented by an implantable cardioverter-defibrillator and sudden cardiac death) between the two groups (8 [36%] of 22 patients vs. 7 [58%] of 12 patients) during long-term follow-up (range 1 to 149 months; mean 38).


CONCLUSIONS
Our data suggest that induction of VF by PVS depends on the severity of depolarization abnormalities but does not predict the recurrence of cardiac events in symptomatic Brugada syndrome, indicating that both depolarization and repolarization abnormalities are important in the development of VF.
Kanda
Munetake
M
Division of Cardiology, Department of Internal Medicine, National Cardiovascular Center, 5-7-1 Fujishiro-dai, Suita, Osaka 565-8565, Japan.
Shimizu
Wataru
W
Matsuo
Kiyotaka
K
Nagaya
Noritoshi
N
Taguchi
Atsushi
A
Suyama
Kazuhiro
K
Kurita
Takashi
T
Aihara
Naohiko
N
Kamakura
Shiro
S
D000328:Adult; D000368:Aged; D002037:Bundle-Branch Block / Q000150:complications / Q000503:physiopathology*; D016757:Death, Sudden, Cardiac / Q000453:epidemiology / Q000209:etiology; D004562:Electrocardiography; D022062:Electrophysiologic Techniques, Cardiac; D004594:Electrophysiology; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008297:Male; D008875:Middle Aged; D013577:Syndrome; D014693:Ventricular Fibrillation / Q000145:classification / Q000209:etiology / Q000503:physiopathology*