A patient with sustained ventricular tachycardia: identification of a responder to amiodarone using signal-averaged electrocardiogram.
A 75-year-old man suffered sustained ventricular tachycardia with syncopal attack. Ventricular tachycardias appeared repeatedly, and an electrical defibrillator was used after an anti-arrhythmic drug, such as lidocaine or mexiletine, proved ineffective. The tachycardias had multiple origins, and the signal-averaged electrocardiogram (SAECG) showed ventricular late potential before the administration of amiodarone. After administration, the filtered QRS and duration of the late potential increased, but the recurrence of tachycardias was suppressed. The reason for this is thought to be that amiodarone blocked the sodium channel and delayed conduction, consequently blocking reentry, because amiodaron has antiarrhymic properties with a prolongation of refractoriness and minimal effect on conduction velocity in ventricular myocardium, and inhibits sympathetic activity, and blocks L-type calcium channel besides the depression of the fast sodium channel. In this case, SAECG predicted to some degree whether or not this patient's ventricular tachycardia would respond to amiodarone.
Kobayashi
Ayaka
A
Department of Digestive and Cardiovascular Medicine, Institute of Health Biosciences, The University of Tokushima Graduate School, Tokushima, Japan.
Nomura
Masahiro
M
Sawa
Yuko
Y
Kawaguchi
Takashi
T
Koshiba
Kunihiko
K
Yamaguchi
Koji
K
Kawano
Tomohito
T
Wakatsuki
Tetsuzo
T
Tabata
Tomotsugu
T
Nisikado
Akiyoshi
A
Ito
Susumu
S
Nakaya
Yutaka
Y
D000368:Aged; D000638:Amiodarone / Q000627:therapeutic use*; D000889:Anti-Arrhythmia Agents / Q000627:therapeutic use*; D004562:Electrocardiography / Q000706:statistics & numerical data; D006801:Humans; D008297:Male; D012815:Signal Processing, Computer-Assisted; D017180:Tachycardia, Ventricular / Q000188:drug therapy* / Q000503:physiopathology
D000889:Anti-Arrhythmia Agents; D000638:Amiodarone