Pacientes con síndrome de Brugada asintomático puede que no necesiten defibrilador automático implantable

Asymptomatic Brugada patients may not need ICDs
February 3, 2010 | Lisa Nainggolan
Nantes, France - In the largest series of Brugada-syndrome patients studied to date, researchers have discovered that arrhythmic event rates appear to be low for asymptomatic patients. In addition, they show that the only predictors of arrhythmic events in Brugada patients are symptoms and spontaneous type 1 ECG.
Gender, family history of sudden cardiac death, inducibility of ventricular tachyarrhythmias during electrophysiological study (EPS), and the presence of a mutation in the SCN5A gene had no predictive value in this series, report Dr Vincent Probst (Hôpital Nord, Nantes, France) and colleagues in their report published online January 25, 2010 in Circulation.
As a result of their findings, they say that guidelines issued in 2005 may need to be revised, because they recommend implantation of an implantable cardioverter defibrillator (ICD) in asymptomatic patients in the event that inducibility of ventricular tachyarrhythmias during EPS is positive.
Event rate per year only 0.5% in asymptomatic patients
Probst et al explain that Brugada syndrome is characterized by a typical ECG pattern of ST-segment elevation in the right precordial leads on ECG and an increased risk of sudden cardiac death (SCD) due to ventricular fibrillation. Patients displaying the Brugada-syndrome ECG pattern were initially considered at high risk of SCD, but recent studies have shown that those without symptoms have a low risk of arrhythmic events, they note.
However, the risk stratification and therapeutic approach in asymptomatic patients is still controversial, they observe.
In this series, they studied 1029 consecutive individuals with Brugada syndrome from four European countries recruited in 11 tertiary centers participating in the FINGER (France, Italy, Netherlands, Germany) Brugada Syndrome Registry. Of the patients, 36% had symptoms (aborted SCD 6%; unexplained syncope 30%), with the remaining 64% asymptomatic.

During a median follow-up of 31.9 months, 51 cardiac events (5%) occurred (44 patients experienced appropriate ICD shocks, and seven died suddenly). The cardiac event rate per year was 7.7% in patients with aborted SCD, 1.9% in those with syncope, and 0.5% in asymptomatic patients.
Risk/benefit of ICD implantation not easy to assess in asymptomatics
"Given the low event rate overall, it remains difficult to recommend a suitable therapeutic approach for asymptomatic patients," Probst and colleagues say. "Although ICDs represent an attractive option to protect patients against SCD, the incidence of ICD-related complications is high in this population, and death related to ICD malfunction has also been reported," they note.
So the risk/benefit profile of ICD implantation "is not easy to assess" in asymptomatic patients, and an open discussion with the patient explaining the potential risks of the disease but also the possible complications of the ICD is "crucial," they observe.
Quinidine therapy may be an alternative in patients refusing the ICD or ineligible for ICD implantation, they add, but they say that available data on this "are limited, and future prospectively designed studies are needed."

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