Brugada Syndrome

Aka: Brugada Syndrome, Brugada, Sudden Arrhythmia Death Syndrome, SADS, Bangungut, Pokkuri, Lai Tai, Sleep Death

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II. Definitions

  1. Brugada Syndrome
    1. Genetically inherited Sodium channelopathy (Sodium channel gene SCN5A)
    2. Presents with Cardiac Syncope, Ventricular Tachycardia, Ventricular Fibrillation, or sudden death
    3. Divided into 3 types, with the first most recognizable (Right Bundle Branch Block, ST Elevation V1-V3)
    4. Brugada often manifests after triggers: Fever, Electrolyte abnormalities, Sodium Channel Blocker drugs

III. Epidemiology

  1. Incidence: Uncommon
    1. Accounts for <5% of Sudden Cardiac Death cases
  2. Family History of sudden death events often present
  3. Most common in men
  4. Greater Incidence in Southeast asia
    1. Northeastern Thailand (40/year per 100,000)
    2. Japan
    3. Philipines

IV. Pathophysiology

  1. J Wave Syndrome
  2. Inherited disorder of myocardial Sodium channels (esp. Sodium channel gene SCN5A)
  3. No cardiac structural abnormalities

V. Symptoms

  1. Often asymptomatic until terminal event with sudden death (40%)
  2. Exertional Syncope history may be present
  3. Agonal Respirations may be present during sleep

VI. Diagnostics: EKG findings

  1. Prolonged QT Interval
  2. Right Bundle Branch Block
  3. Brugada Sign
    1. Seen best in the right precordial leads (V1-V3)
    2. End of QRS marked by significant upward deflection (J Point Elevation)
    3. ST Segment Elevation (leads v1-v3)
  4. Types
    1. Type 1 (coved-type, wide and large J Wave)
      1. Most concerning of the J Wave Patterns
      2. J-Wave amplitude >2 mm (or mV) at peak AND
      3. Followed by negative T Wave (minimal or no isoelectric component)
    2. Type 2 (saddleback pattern)
      1. J-Wave amplitude >2 mm (or mV) at peak AND
      2. ST Elevation >1 mm above baseline, gradually down-sloping AND
      3. Positive or biphasic T Wave
    3. Type 3
      1. Right precordial ST Elevation

VII. Diagnosis

  1. Shanghai Scoring System
    1. https://www.sciencedirect.com/science/article/pii/S2405500X18301695#tbl1
    2. Score based on EKG, history, Family History, Genetic Testing
    3. Interpretation (score >3.5 probable Brugada, 2-3 possible Brugada Syndrome)
      1. Brugada Type 1 criteria are typically met without specific testing
      2. Brugada Types 2-3 typically require electrophysiology for diagnosis confirmation

VIII. Differential Diagnosis: RBBB Pattern

  1. See Right Bundle Branch Block
  2. Early Repolarization
    1. Calculate Corrado Index
      1. Ratio = (J Point at ST start)/(J Point at 80 ms later)
      2. Ratio >1 AND a downsloping ST Segment is consistent with Brugada Type 1

IX. Labs

  1. Genetic Test is available

X. Management

  1. Disposition
    1. Symptomatic, type I Brugada morphology is most concerning
      1. Admit patients with Syncope and suspected Brugada Syndrome and consult electrophysiology
    2. Asymptomatic patients with incidental Brugada findings on ekg
      1. May be discharged with electrophysiology follow-up
  2. Treatment Options
    1. Management decisions are based on symptomatic versus asymptomatic Brugada findings
    2. Internal Cardiac Defibrillator (ICD)
    3. Quinidine
  3. Exercise and sports participation are not contraindicated
    1. However avoid significant Hypothermia or hyperthermia
  4. Avoid provocative factors
    1. Treat fever
    2. No Cocaine
    3. Avoid excessive Alcohol

XI. Complications

  1. Ventricular Tachycardia
  2. Cardiac Arrest with Ventricular Fibrillation
  3. Sudden Cardiac Death
    1. Mean age of onset 41 years old (but range of onset varies from newborns to elderly)

XII. Prognosis

  1. Mortality: 10% (without ICD placement)

XIII. References

  1. Krishnan (2018) Cardiac Arrhythmias Conference, UMN, Minneapolis, MN
  2. Joshi and Dermark (2016) Crit Dec Emerg Med 30(8):3-12
  3. Antzelevitch (2003) J Am Coll Cardiol 41(10):1665-71 [PubMed]
  4. Brugada (1992) J Am Coll Cardiol 20(6):1391-6 [PubMed]
  5. Littmann (2003) Am Heart J 145(5):768-78 [PubMed]
  6. Meyer (2003) Am Fam Physician 68(3):483-8 [PubMed]

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