Case:

A 16 year-old male presents to the ED after a syncopal episode. He currently feels well and wants to go home. Below is his EKG, what do you think?

 

Brugada-type-1

 

Discussion:

The above presentation (syncopal event) paired with this EKG is concerning for the Brugada syndrome.

Epidemiology:

  • The Brugada syndrome was first described in 1992 by Drs. Pedro and Josep Brugada in a case report of 8 patient with aborted sudden cardiac death (SCD), though cases of sudden unexplained nocturnal death (SUND) had been described previously in various southeast Asian populations (Juang JM et al, 2004).
  • Some estimate that 4-12% of SCD can be attributed to the syndrome, with a higher prevalence in SE Asian populations (Gourraud JB et al, 2016)
  • Median age of presentation is 41, though has be reported in neonates through the elderly.
  • While many mutations have been described, the Brugada syndrome appears to result from mutations in the Na+ channel, affecting the SCN5A gene (Behere SP et al, 2015)
    • Note: Only 20% of patients with Brugada syndrome have a documented mutation in the SCN5A gene. Studies show a autosomal dominant transmission with incomplete penetrance  (Juang JM et al, 2004).

Clinical Presentation:

  • In the original description of the syndrome, the Brugada brothers noted that all patients presented with syncope, with 5/7 progressing immediately to cardiac arrest and the other 2 progressing to cardiac arrest over the next 2 weeks
    • Registry data indicates that almost 1/3 present with syncope, 6% with SCD, though >60% were asymptomatic at the time of diagnosis (Probst V et al, 2010)
      • NOTE: Registry listed above excluded children, so interpret with caution
  • Sustained Polymorphic Ventricular Tachycardia is the most common rhythm noted to precipitate SCD

EKG Findings and Diagnosis

  • ST elevation in V1-3 with right bundle block morphology is common, with “coved pattern” in V1-3  negative T wave (referred to as “Type 1;” this is the only pathognomonic EKG pattern)
    • In most cases, no reciprocal ST-depression noted (Juang JM et al, 2004).
  • EKGs in Brugada syndrome tend to be variable and at times are even normal
  • In patients with normal EKG, class Ia or Ic antiarrhythmic drugs ( potently blocks Na channel) may unmask the Brugada pattern (Juang JM et al, 2004).
  • Two other patterns have been described, though are considered less significant
  • To be considered diagnostic of Brugada syndrome the EKG findings must be combined with the following clinical findings:
    • Polymorphic ventricular tachycardia
    • syncope
    • ventricular fibrillation
    • Family history of early sudden cardiac death (<45)
  • Workup must also exclude other causes that lead to ST-elevation (e.g. acute pericarditis, arrhythmogenic right ventricular dysplasia (ARVD), Prinzmetal angina, etc).

Treatment

  • Implantable cardioverter-defibrillator (ICD) is the only strategy to prevent SCD
  • Patients should also be advised to avoid alcohol, certain drugs, and treat fevers aggressively (Refaat MM, 2016).
Resident Reviewer: Vanessa Tommey, MD

References

  1. Brugada P, Brugada J. Right bundle branch block, persistent ST segment elevation and sudden cardiac death: a multicenter report. J Am Coll Cardiol 1992;20:1391–6
  2. Juang JM et al. “Brugada syndrome–an under-recognized electrical disease in patients with sudden cardiac death.” Cardiology. 2004;101(4):157-69
  3. Gourraud JB et al. “The Brugada Syndrome: A Rare Arrhythmia Disorder with Complex Inheritance.” Front Cardiovasc Med. 2016 Apr 25;3:9.
  4. Behere SP et al. “Inherited arrhythmias: The cardiac channelopathies.” Ann Pediatr Cardiol. 2015 Sep-Dec; 8(3): 210–220.
  5. Probst V et al. “Long-Term Prognosis of Patients Diagnosed With Brugada Syndrome.” Circulation. 2010;121(5):635-643.
  6. Alley P. “What is Brugada Syndrome?” http://lifeinthefastlane.com/what-is-brugada-syndrome/