What is the difference between a Brugada pattern and Brugada syndrome on an electrocardiogram (ECG)?

Brugada Pattern vs. Brugada Syndrome

A Brugada pattern is simply an ECG finding (Type 1 coved ST-elevation ≥2 mm in V1-V2), while Brugada syndrome is a clinical diagnosis requiring this ECG pattern PLUS either symptoms (syncope, cardiac arrest, documented ventricular arrhythmias) OR a significant family history of sudden cardiac death. 1, 2

Key Distinguishing Features

Brugada Pattern (ECG Finding Only)

• The Type 1 Brugada ECG pattern consists of a coved rSr' morphology with ST-segment elevation ≥2 mm and terminal T-wave inversion in leads V1, V2, and V3. 3
• This pattern may appear spontaneously, be induced by sodium channel blockers (ajmaline, flecainide, procainamide), or be unmasked by fever, vagotonic states, or certain medications. 1
• The ECG pattern is highly dynamic and transient—only 2% of patients show a persistent coved-type pattern, while 33% fluctuate between diagnostic and non-diagnostic ECGs. 4
• The pattern can be distinguished from benign early repolarization in athletes using the Corrado index: Type 1 Brugada shows downsloping ST-segments with STJ/ST80 ratio >1, while early repolarization shows upsloping ST-segments with STJ/ST80 ratio <1. 3

Brugada Syndrome (Clinical Diagnosis)

• Brugada syndrome requires the Type 1 ECG pattern PLUS at least one of the following clinical criteria: 2

  • History of aborted cardiac arrest
  • Documented spontaneous sustained ventricular tachycardia
  • Syncope or seizures likely due to ventricular arrhythmias
  • Family history of sudden cardiac death <50 years of age
  • Presence of Type 1 ECG pattern in family members

• The syndrome is an inherited primary electrical disease predisposing to ventricular tachyarrhythmias and sudden death, particularly during enhanced vagal tone (rest or sleep). 3

Critical Clinical Implications

Risk Stratification

• Spontaneous Type 1 ECG pattern carries significantly worse prognosis than drug-induced pattern. 1
• Patients with syncope AND spontaneous Type 1 pattern have 6-fold higher risk of cardiac arrest compared to asymptomatic patients with spontaneous pattern. 1
• Annual arrhythmic event rates vary dramatically: 13.5% in cardiac arrest survivors, 3.2% in patients with syncope, and 1% in asymptomatic patients. 1
• Patients with >50% of ECGs showing coved-type pattern have significantly higher rates of inducible ventricular fibrillation than those with <50% diagnostic ECGs. 4

Management Algorithm

For Type 1 Brugada Pattern on ECG:

1. First, confirm the finding: Verify correct lead placement, repeat ECG, and perform high precordial lead ECG with V1-V2 in 2nd or 3rd intercostal space. 3
2. Exclude Brugada phenocopy: Rule out reversible causes including fever, electrolyte abnormalities (hyperkalemia), medications with sodium channel blocking properties, myocardial ischemia, and mechanical compression. 5
3. Obtain detailed history: Specifically ask about personal syncope/seizures, family history of sudden death <50 years, unexplained drowning, and exertional syncope. 3
4. Refer to electrophysiologist regardless of symptoms for further evaluation when Type 1 pattern is confirmed. 3

For Confirmed Brugada Syndrome:

• ICD implantation (Class I recommendation): Cardiac arrest survivors or documented spontaneous sustained ventricular tachycardia. 1
• Consider ICD (Class IIa recommendation): Spontaneous Type 1 pattern AND history of syncope. 1
• Lifestyle modifications for all patients: Avoid drugs inducing ST-elevation, avoid excessive alcohol and large meals, aggressively treat fever with antipyretics. 1
• Consider quinidine: For patients with ICD contraindications/refusal or recurrent ICD shocks. 1

Common Pitfalls to Avoid

• Do not diagnose Brugada syndrome based on ECG alone—the clinical context (symptoms, family history) is essential for diagnosis. 2
• Do not rely on a single normal ECG to exclude the diagnosis—serial ECGs are mandatory given the high prevalence (65%) of fluctuations between diagnostic and non-diagnostic patterns. 4
• Do not confuse with early repolarization in athletes—use the Corrado index and look for the characteristic downsloping ST-segment in Brugada. 3
• Do not miss Brugada phenocopy—always identify and treat reversible underlying causes to avoid unnecessary ICD implantation. 5
• Asymptomatic patients with only drug-induced Type 1 pattern have low risk and do not require chronic therapy despite positive testing. 1

Family Screening Considerations

• Genetic testing identifies SCN5A mutations in approximately 20-30% of cases but does not influence prognosis or treatment decisions. 1
• Family screening with ECGs should be considered for first-degree relatives, particularly when Type 1 pattern is identified. 1