SAQ 122 – Cardiology – Brugada syndrome after syncope

Question 1. Brugada syndrome after syncope.

a. ECG abnormalities

• Sinus tachycardia around 100 bpm.
• ST elevation about 4 mm in V1-V2.
• Downsloping or coved ST elevation / Brugada sign followed by inverted T wave.
• ST depression about 2 mm in V4-V6, II, III, and aVF.
• T-wave abnormalities in V1-V2 and aVL; biphasic T wave in V3.

b. Significance

• In association with syncope, this is diagnostic of Brugada syndrome.
• Needs admission to a monitored bed to monitor for malignant arrhythmia.
• High untreated mortality from ventricular fibrillation, around 10% per year.
• Type 1 coved ST elevation greater than 2 mm in more than one of V1-V3 followed by a negative T wave is the potentially diagnostic ECG pattern.

c. Pathophysiological basis

• Mutation in a sodium channel gene causing a sodium channelopathy.
• May be spontaneous or familial with autosomal dominant clustering.
• Subendocardial fibrosis or replacement of myocardium with adipose tissue.

d. Precipitants

• Drugs such as sodium-channel blockers, calcium-channel blockers, beta blockers, nitrates, and cholinergic stimulation.
• Alcohol.
• Cocaine.
• Fever.
• Myocardial ischaemia.
• Hypokalaemia.
• Post-DCR.
• Hypothermia.

e. Associated clinical features

• Ventricular fibrillation.
• Polymorphic ventricular tachycardia.
• Family history of sudden cardiac death under 25 years.
• Coved-type ECGs in family members.
• Inducible VT with flecainide or electrical stimulation.
• Nocturnal agonal respiration.

f. Treatment

• AICD.
• Quinidine if AICD is contraindicated, for example in a neonate.