Brugada Syndrome

An ECG abnormality with a high incidence of sudden death in patients with structurally normal hearts.

Aetiology

• Most cases due to a mutation in a cardiac sodium channel gene (sodium channelopathy)
  • Most are spontaneous but occasionally there are hereditary cases

Features/Diagnostic criteria

• NB Can be transient and/or can be unmasked/augmented by a number of factors e.g. fever, ischaemia, drugs (notably sodium channel blockers e.g. flecainide; calcium channel blockers; alpha receptor agonists; beta blockers; nitrates; cocaine; alcohol), hypokalaemia, hypothermia, cardioversion
• ECG findings
  • Type 1
    • Coved ST segment elevation >2mm in >1 of V1-V3, followed by a negative T wave (Brugada sign)
  • Note that this is the only sign that is potentially diagnostic.  It must be associated with one of the following to make the diagnosis:
    • Episode of VF or polymorphic VT
    • Family history of sudden cardiac death <45 years old
    • Coved type ECGs in family members
    • Inducibility of VT with programmed electrical stimulation
    • Syncope
    • Nocturnal agonal respiration
  • Type 2 sign has >2mm of saddleback shaped ST elevation and type 3 can be either morphology but with <2mm elevation

Other investigations

• Where the patient is asymptomatic, it may be appropriate to carry out electrophysiological testing to try and induce VT in patients with ECG changes.  However, this is often not conclusive and does carry significant risk.
  • Alternatively, attempting to induce VT with a dose of flecainide may also help with diagnosis, but has similarly poor diagnostic capability and can be dangerous.

Management

• The only proven management for Brugada syndrome is an ICD device.