What is the workup and diagnosis for a patient suspected of having Brugada syndrome?

Brugada Syndrome: Workup and Diagnosis

For patients suspected of having Brugada syndrome, diagnosis requires documentation of a spontaneous or drug-induced type 1 Brugada electrocardiographic pattern, with pharmacological challenge using sodium channel blockers being useful when the spontaneous pattern is absent. 1, 2

Diagnostic Criteria

ECG Findings

• Type 1 Brugada pattern (diagnostic): Coved ST-segment elevation ≥2 mm followed by a negative T-wave in the right precordial leads (V1-V3) 3
• This pattern may be:
  • Spontaneous (present on baseline ECG)
  • Drug-induced (revealed during pharmacological challenge)

Pharmacological Challenge

• Indicated when Brugada syndrome is suspected but spontaneous type 1 pattern is absent 1, 2
• Sodium channel blockers used for provocation:
  • Ajmaline
  • Flecainide
  • Procainamide 2, 4
• Safety precautions during drug challenge:
  • Must be performed under careful cardiac monitoring
  • Should be terminated immediately if:
    • Ventricular arrhythmias develop
    • Marked QRS widening occurs
    • Type 1 Brugada pattern emerges 2

Risk Stratification

After diagnosis, risk assessment is critical for treatment decisions:

High-Risk Features

• Spontaneous (not drug-induced) type 1 Brugada ECG pattern 2, 5
• History of cardiac arrest 2
• History of sustained ventricular tachycardia 2
• Recent syncope presumed due to ventricular arrhythmia 1

Medium-Risk Features

• Asymptomatic patients with spontaneous type 1 ECG pattern 2
• Ventricular fibrillation during programmed ventricular stimulation 2

Low-Risk Features

• Asymptomatic patients with only drug-induced type 1 ECG pattern 2

Additional Diagnostic Evaluations

Electrophysiological Study

• May be considered for further risk stratification in asymptomatic patients with spontaneous type 1 Brugada pattern 1
• Programmed ventricular stimulation using single and double extrastimuli 1

Genetic Testing

• May be useful to facilitate cascade screening of relatives 1, 2
• SCN5A is the most common gene associated with Brugada syndrome 5, 6
• Important note: Current genetic test results do not significantly influence prognosis or treatment decisions 2

Special Considerations

Fever Management

• Fever can trigger or unmask Brugada ECG pattern and increase arrhythmic risk 2, 5
• Aggressive antipyretic therapy is recommended during febrile illnesses 2

Medication Precautions

• Patients should avoid medications that can induce ST-segment elevation in right precordial leads 2
• High-risk medications include:
  • Sodium channel blockers
  • Certain calcium channel blockers
  • Beta-blockers
  • Tricyclic antidepressants 2
• Patients should check medication safety on www.brugadadrugs.org before taking new drugs 2

Diagnostic Algorithm

1. Initial evaluation:

   • 12-lead ECG with right precordial leads positioned in standard and higher intercostal spaces
   • Detailed personal and family history of syncope, seizures, or sudden cardiac death

2. If spontaneous type 1 pattern is present:

   • Diagnosis is confirmed
   • Proceed to risk stratification

3. If type 1 pattern is absent but Brugada syndrome is suspected:

   • Perform pharmacological challenge with sodium channel blockers
   • If type 1 pattern is induced, diagnosis is confirmed

4. After diagnosis:

   • Consider genetic testing (primarily for family screening)
   • Evaluate for risk factors to guide management decisions
   • Consider electrophysiological study in selected cases

This systematic approach to diagnosis and risk stratification allows for appropriate management decisions, which may include observation for low-risk patients or interventions such as ICD implantation for high-risk individuals 1, 2.