Brugada Syndrome
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Direct answer
Brugada syndrome is an inherited channelopathy causing sudden death in structurally normal hearts, diagnosed by a coved ST-segment elevation of at least 2 mm followed by a negative T wave in the right precordial leads. The defect is usually a loss of sodium channel function, although most patients carry no identified SCN5A variant. An implantable cardioverter-defibrillator is the mainstay of prevention for high-risk patients, and fever is the classic trigger.
What you must remember
- Type 1 pattern: coved ST elevation of 2 mm or more with a negative T wave in V1 or V2; types 2 and 3 are only suggestive.
- Unmasking: a sodium channel blocker challenge with ajmaline or flecainide can reveal a concealed type 1 pattern, in a monitored setting.
- Genetics: autosomal dominant with incomplete penetrance and male predominance; SCN5A is the commonest gene, and the disease is more frequent in South-East Asia.
- Triggers: fever, large meals, alcohol, cocaine and sodium channel blockers; events cluster at night during sleep.
- Mimics: pulmonary embolism, hyperkalaemia, ischaemia and arrhythmogenic right ventricular cardiomyopathy can each produce a Brugada-like pattern.
- Acute care: prompt antipyretics for fever, avoidance of sodium channel blockers, and isoprenaline for electrical storm.
- Prevention: an ICD for survivors of cardiac arrest and for a spontaneous type 1 pattern with syncope; risk stratification guides asymptomatic patients.
A night-time collapse after a febrile illness
A 28-year-old man is found unresponsive in bed at night, a day after a febrile sore throat. Resuscitation restores circulation, and a recording after recovery shows a coved ST segment with a negative T wave in V1 and V2, although his earlier ECG was read as normal.
- Confirm the type: The pattern must be type 1, since types 2 and 3 do not diagnose the syndrome alone.
- Check the context: A structurally normal heart with nocturnal arrest or syncope fits the disease.
- Unmask a concealed pattern: If only a type 2 or 3 pattern is seen, a monitored ajmaline or flecainide challenge can reveal the type 1 morphology.
- Screen relatives: Autosomal dominant inheritance means first-degree relatives may carry the same pattern, so they are screened.
- Decide on the ICD: Resuscitated patients receive a defibrillator, as do those with a spontaneous type 1 pattern and syncope. Asymptomatic patients are assessed with risk stratification.
- Counsel the family: Fever is treated promptly, and sodium channel blocking drugs are avoided.
Where the examiner sets the trap
Four traps recur in Brugada questions.
- Trap: calling every right precordial ST elevation Brugada. Correct: pulmonary embolism, early repolarisation and arrhythmogenic right ventricular cardiomyopathy can mimic the pattern, so the cause must be found first.
- Trap: offering flecainide as routine therapy for a known patient. Correct: a sodium channel blocker is given only to unmask a concealed pattern in a monitored setting, never to treat a known patient.
- Trap: choosing a beta-blocker for a young man who collapses during a febrile illness. Correct: name the syndrome and treat the fever promptly with antipyretics.
- Trap: quinidine as the preventive answer. Correct: quinidine is a recognised adjunct in selected patients, but for prevention in a high-risk patient the ICD remains the answer.
Frequently asked questions
Which ECG pattern is diagnostic of Brugada syndrome?
The diagnostic pattern in Brugada syndrome is type 1, showing coved ST-segment elevation of at least 2 mm followed by a negative T wave in one or more right precordial leads. Types 2 and 3 are not diagnostic alone and need a sodium channel blocker challenge.
Is an ICD needed in every patient with Brugada syndrome?
An ICD is not needed in every patient with Brugada syndrome. Survivors of cardiac arrest and patients with a spontaneous type 1 pattern and syncope are high risk and usually receive one, while asymptomatic patients are assessed with risk stratification.
What triggers arrhythmias in Brugada syndrome?
Fever is the classic trigger for arrhythmias in Brugada syndrome, and events often happen at night during sleep. Large meals, alcohol, cocaine and sodium channel blocking drugs can also provoke the arrhythmia.
Which drug is used to unmask a concealed Brugada pattern?
Ajmaline is given intravenously in a monitored setting to unmask a concealed type 1 pattern, and flecainide is an alternative. The test is diagnostic only and is never given to a patient already known to have the syndrome.
What conditions can mimic a Brugada-like ECG?
Right ventricular strain from pulmonary embolism, arrhythmogenic right ventricular cardiomyopathy, hyperkalaemia and early repolarisation can all produce a Brugada-like ST pattern. The cause must be excluded before the diagnosis is made.