Low risk for arrhythmic events in asymptomatic patients with drug-induced type 1 ECG. Do patients with drug-induced Brugada type ECG have poor prognosis? (Con).
The type 1 ST-segment elevation is diagnostic for Brugada syndrome (BS) and its presence may sometimes be associated with a high risk of arrhythmic events. The type 1 ECG is also known to be unmasked by administration of sodium-channel blockers in equivocal or suspected cases of BS, and the drug-challenge test is frequently used in the diagnostic approach. In large cohort studies the spontaneous appearance of the type 1 ECG with symptoms of aborted sudden death or unexplained syncope are indicative of a poor prognosis for patients with BS compared with not having clinical symptoms. Therefore, the spontaneous type 1 ECG appears to represent an important predictive sign for cardiac events. It is unknown, however, whether or not the drug-induced type 1 ECG is as useful as the spontaneous type 1 for predicting cardiac events in asymptomatic subjects showing non-type 1 ECG. Review of the literature for large cohort studies indicates that there is a low incidence of arrhythmic events in asymptomatic patients with either the spontaneous or drug-induced type 1 ECG compared with symptomatic subjects, and the drug-induced type 1 ECG in asymptomatic patients does not add to an increase in arrhythmic risk. Therefore, drug testing to unmask the type 1 ECG in asymptomatic patients with a non-type 1 BS ECG does not have an additional value for risk stratification of cardiac events, although it might be useful in symptomatic patients showing only the non-type 1 ECG.
Department of Cardiology, Yokohama Minami Kyosai Hospital, Yokohama, Japan. nisizaki@yhb.att.ne.jp
Mitsuhiro
M
Nishizaki
Harumizu
H
Sakurada
Noriyoshi
N
Yamawake
Akiko
A
Ueda-Tatsumoto
Masayasu
M
Hiraoka
D000200:Action Potentials; D001145:Arrhythmias, Cardiac / Q000150:complications / Q000175:diagnosis* / Q000378:metabolism / Q000503:physiopathology / Q000628:therapy; D053840:Brugada Syndrome / Q000150:complications / Q000175:diagnosis* / Q000378:metabolism / Q000503:physiopathology / Q000628:therapy; D016757:Death, Sudden, Cardiac / Q000209:etiology; D017147:Defibrillators, Implantable; D004554:Electric Countershock / Q000295:instrumentation; D004562:Electrocardiography; D022062:Electrophysiologic Techniques, Cardiac / Q000009:adverse effects; D006329:Heart Conduction System / Q000187:drug effects / Q000378:metabolism / Q000503:physiopathology*; D006801:Humans; D011237:Predictive Value of Tests; D011379:Prognosis; D018570:Risk Assessment; D012307:Risk Factors; D026941:Sodium Channel Blockers / Q000009:adverse effects; D017180:Tachycardia, Ventricular / Q000209:etiology; D013997:Time Factors; D014693:Ventricular Fibrillation / Q000209:etiology
D026941:Sodium Channel Blockers