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)

• Published in: Circulation Journal Vol. 74; no. 11; pp. 2464 - 2473
• Main Authors: Sakurada, Harumizu, Ueda-Tatsumoto, Akiko, Nishizaki, Mitsuhiro, Hiraoka, Masayasu, Yamawake, Noriyoshi
• Format: Journal Article
• Language: English
• Published: Japan The Japanese Circulation Society 01.11.2010
• Subjects: Action Potentials; Arrhythmia; Arrhythmias, Cardiac - complications; Arrhythmias, Cardiac - diagnosis; Arrhythmias, Cardiac - metabolism; Arrhythmias, Cardiac - physiopathology; Arrhythmias, Cardiac - therapy; Brugada syndrome; Brugada Syndrome - complications; Brugada Syndrome - diagnosis; Brugada Syndrome - metabolism; Brugada Syndrome - physiopathology; Brugada Syndrome - therapy; Death, Sudden, Cardiac - etiology; Defibrillators, Implantable; Electric Countershock - instrumentation; Electrocardiography; Electrophysiologic Techniques, Cardiac - adverse effects; Heart Conduction System - drug effects; Heart Conduction System - metabolism; Heart Conduction System - physiopathology; Humans; Implantable cardioverter defibrillator (ICD); Predictive Value of Tests; Prognosis; Risk Assessment; Risk Factors; Sodium Channel Blockers - adverse effects; Sodium-channel blockers; Tachycardia, Ventricular - etiology; Time Factors; Ventricular Fibrillation - etiology
• ISSN: 1346-9843; 1347-4820; 1347-4820
• DOI: 10.1253/circj.CJ-10-0878

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 type1 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. (Circ J 2010; 74: 2464-2473)