Brugada Syndrome
Cardiology
Illness script · Cardiology
Brugada Syndrome
Autosomal dominant sodium channelopathy causing a characteristic coved ST-elevation ECG pattern and risk of sudden cardiac death from VT/VF.
This illness script for Brugada Syndrome covers predisposing factors, classic presentation, mechanism, workup, management, and the clinical pivots that separate it from look-alikes—written for USMLE Step 1 and clerkship reasoning.
01
Predisposing factors
- Male sex strongly predominant (~8:1 male:female ratio)
- Southeast Asian descent (highest global prevalence)
- Peak presentation age 30–50, often during sleep or rest
- SCN5A loss-of-function mutation in ~20–30% of cases
- Family history of sudden cardiac death or Brugada syndrome
- Fever, alcohol, or sodium-channel-blocking drugs can unmask pattern
02
Presentation
- Classic: syncope or aborted sudden cardiac death in young-middle-aged male
- Arrhythmias occur characteristically at rest, during sleep, or with fever
- Type 1 ECG (diagnostic): coved ≥2 mm J-point/ST elevation + T-wave inversion in V1–V2
- Type 2 (saddle-back) is NOT diagnostic on its own
- Many patients are asymptomatic; pattern found incidentally on routine ECG
- No structural heart disease on imaging
03
Pathophysiology
- SCN5A mutation reduces Nav1.5 sodium channel function in RV epicardium
- Loss of inward Na⁺ current unmasks dominant outward Ito (transient outward K⁺) current
- Creates heterogeneous RV repolarization → phase 2 reentry → VT/VF
- ST elevation reflects action potential dome loss in RV outflow tract epicardium
04
Diagnostics
- 12-lead ECG: spontaneous Type 1 coved pattern in V1–V2 is diagnostic
- Move leads to 2nd–3rd ICS to increase sensitivity if standard leads equivocal
- Sodium-channel blocker challenge (ajmaline or flecainide) unmasks Type 1 in concealed cases
- Genetic testing (SCN5A): confirms in ~25% but negative result does not exclude diagnosis
- EPS for risk stratification remains controversial; EF and echo typically normal
05
Management
- ICD is the ONLY proven therapy to prevent sudden cardiac death
- Symptomatic patients (syncope, aborted SCD) → ICD implantation
- Asymptomatic spontaneous Type 1 → individualized; ICD often recommended with strong family history
- Quinidine (blocks Ito) used for recurrent VT/VF storms or ICD shocks
- Isoproterenol IV for acute electrical storm
- Avoid: Class IC/IA antiarrhythmics (flecainide, procainamide), TCAs, cocaine, excessive alcohol
- Aggressively treat fever — antipyretics can normalize ECG and reduce arrhythmia risk
06
Clinical pivots
How to separate this script from the look-alikes that show up on exams and on the wards.
ARVC (Arrhythmogenic Right Ventricular Cardiomyopathy)
ARVC causes structural RV changes (epsilon wave, fatty replacement) with exercise-induced arrhythmias; Brugada has no structural disease and arrhythmias occur at rest/sleep.
Long QT Syndrome
Long QT prolongs the QTc interval triggering torsades de pointes; Brugada has a normal QTc with ST-elevation coved pattern in V1–V2.
Acute Anterior STEMI
STEMI ST elevation is dynamic with ischemic symptoms and reciprocal changes; Brugada ST elevation is isolated to V1–V2, coved, and without chest pain or troponin rise.
Early Repolarization Syndrome
Early repolarization shows benign J-point elevation in inferior/lateral leads with notching; Brugada is specifically coved in right precordial leads (V1–V2) with T-wave inversion.
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Educational use only. This illness script is a study framework, not medical advice. Confirm decisions with current guidelines and your clinical supervisors.