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Brugada Syndrome

No contraindication to pregnancy; however, genetic counseling is recommended in view of the genetic cause and transmission of this disease. ### Epidemiology

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Epidemiology

The incidence and prevalence are unknown. It can be recognized in patients of any age, however primarily affects young adult (80% male) пїЅ

Risk Factors

None пїЅ

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: пїЅ

  • 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"пїЅ 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 пїЅ

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 пїЅ

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 пїЅ

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 пїЅ

Additional Reading

1Alings пїЅM, Wilde пїЅA. "Brugada"пїЅ syndrome: Clinical data and suggested pathophysiological mechanism. Circulation. 1999;99:666-673. пїЅ[View Abstract]2Brugada пїЅJ, Brugada пїЅP. Further characterization of the syndrome of right bundle branch block, ST segment elevation, and sudden cardiac death. J Cardiovasc Electrophysiol. 1997;8:325-331. пїЅ[View Abstract]3Gussak пїЅI, Antzelevitch пїЅC, Bjerregaard пїЅP. The Brugada syndrome: Clinical, electrophysiologic and genetic aspects. J Am Coll Cardiol. 1999;33:5-15. пїЅ[View Abstract]4Chen пїЅPS, Priori пїЅSG. The Brugada syndrome. J Am Coll Cardiol 2008:51:1176-1180. пїЅ[View Abstract]5Nademnee пїЅK, Verakul пїЅG, Mower пїЅM. 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) пїЅ