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No contraindication to pregnancy; however, genetic counseling is recommended in view of the genetic cause and transmission of this disease.
Epidemiology
The incidence and prevalence are unknown. It can be recognized in patients of any age, however primarily affects young adult (80% male) �
Risk Factors
None �
Etiology
- Genetic abnormality of SCN5A and other genes in 15-20%
- Missense mutation: Channel recovers from inactivation more rapidly than normal.
- Frameshift mutation renders channel nonfunctional, which increases dispersion of refractoriness and repolarization.
Diagnosis
Signs and symptoms: �
- Asymptomatic
- Cardiac arrest
- Syncope
Tests
- EKG shows RBBB pattern and ST elevation in leads V1 and V2.
- EKG abnormalities may be unmasked by PO flecainide or IV procainamide.
- Signal-averaged EKG often shows late potentials, even in absence of r"� waves in right precordial leads.
- Ventricular arrhythmias provocable by programmed stimulation at electrophysiologic study
- Endomyocardial biopsies have been done in selected cases to exclude arrhythmogenic RV dysplasia.
Lab
No test available �
Imaging
- Echo to exclude cardiomyopathy
- Coronary angiography to exclude ischemia
- Ventriculography to exclude cardiomyopathy
- Cardiac MRI to exclude arrhythmogenic RV dysplasia
Surgery
Electrophysiologic study: Role in diagnosis and risk stratification remains controversial �
Differential Diagnosis
- Simple RBBB: Typically does not have ST elevation (present in Brugada syndrome), and has wide slurred S wave in V6 and lead I (not present in Brugada syndrome)
- Acute MI (because of ST elevation)
- LV aneurysm
- Myocarditis
- RV infarction
- Duchenne muscular dystrophy
- Long QT syndrome (because of polymorphic ventricular tachycardia)
- Hypercalcemia
- Hyperkalemia
Treatment
Medication
- In general, drug therapy is apparently ineffective, including β-blockers.
- Drugs that block transient outward current (I-to) current (ie, quinidine and disopyramide) may be efficacious.
Additional Treatment
General Measures
- Because drug therapy is thought to be ineffective, implantation of an implantable cardioverter-defibrillator (ICD) is usually recommended in symptomatic (syncope, sudden death) patients.
- The management of asymptomatic patients remains controversial.
Surgery
None, except implantation of an ICD �
In-Patient Considerations
Admission Criteria
- If the presentation of the Brugada syndrome is syncope or cardiac arrest, ICD implantation is usually recommended.
- If the syndrome is diagnosed incidentally, risk of disease (cardiac arrest) must be discussed.
Ongoing Care
Follow-Up Recommendations
Patient Monitoring
- Once diagnosis is established, the patient should be seen by an electrophysiologist knowledgeable about Brugada syndrome.
- Syncope and sudden death would be indication to initiate treatment (ie, ICD).
- Avoid class I antiarrhythmic drugs that block I-Na > Ito (ie, procainamide and flecainide). Quinidine may have a protective role in selected patients.
Patient Education
- No intervention is known to prevent cardiac arrest. New drugs that selectively block Ito may be effective.
- Sudden death is a major risk of disease.
- Unknown if mental stress and alcohol are provocative factors
Prognosis
Guarded �
Additional Reading
1Alings �M, Wilde �A. "Brugada"� syndrome: Clinical data and suggested pathophysiological mechanism. Circulation. 1999;99:666-673. �[View Abstract]2Brugada �J, Brugada �P. Further characterization of the syndrome of right bundle branch block, ST segment elevation, and sudden cardiac death. J Cardiovasc Electrophysiol. 1997;8:325-331. �[View Abstract]3Gussak �I, Antzelevitch �C, Bjerregaard �P. The Brugada syndrome: Clinical, electrophysiologic and genetic aspects. J Am Coll Cardiol. 1999;33:5-15. �[View Abstract]4Chen �PS, Priori �SG. The Brugada syndrome. J Am Coll Cardiol 2008:51:1176-1180. �[View Abstract]5Nademnee �K, Verakul �G, Mower �M. Defibrillator versus beta-blockers for unexplained death in Thailand (DEBUT): A randomized clinical trial. Circulation. 2003;107:2221-2226.6 www.netvision.be/brugada
See Also
- Implantable cardioverter-defibrillator
- Long QT syndrome
- Sudden death
- Ventricular fibrillation
- Ventricular tachycardia
Codes
ICD9
- 426.4 Right bundle branch block
- 746.89 Other specified congenital anomalies of heart
SNOMED
418818005 brugada syndrome (disorder) �