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Brugada syndrome is an inherited disorder of cardiac electrophysiology causing an increased risk of syncope and sudden death.

Several different mutations are involved, most affecting the SCN5A gene that encodes the α-subunit of the voltage-dependent cardiac Na channel. Typically, patients have no structural heart disease. Nevertheless, relationships with other genetic and acquired structural heart diseases are increasingly being recognized, as are overlap syndromes with LQT3 and with arrhythmogenic right ventricular dysplasia (ARVD).

In some patients, Brugada syndrome has no clinical expression. However, in many patients it leads to syncope or sudden cardiac death due to polymorphic VT and ventricular fibrillation. Events occur more often at night and are not usually related to exercise. Events may also be brought on by fever and by treatment with certain drugs including Na channel blockers, β-blockers, tricyclic antidepressants, lithium Some Trade Names
ESKALITH
LITHOBID
LITHONATE
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, and cocaine.

Initial diagnosis is based on a characteristic ECG pattern (type 1 Brugada ECG pattern—see Fig. 19: Arrhythmias and Conduction Disorders: Type 1 Brugada syndrome.) with prominent ST elevation in V₁ and V₂ (sometimes involving V₃) that causes the QRS complex in these leads to resemble RBBB. The ST segment is coved and descends to an inverted T-wave. Lesser degrees of these patterns (type 2 and type 3 Brugada ECG patterns) are not considered diagnostic. The type 2 and type 3 patterns may change to a type 1 pattern spontaneously, with fever, or in response to drugs. The latter is the basis of a challenge diagnostic test usually using ajmaline or procainamide Some Trade Names
PROCAN SR
PRONESTYL
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. Diagnosis should be considered in patients with unexplained cardiac arrest or syncope, or a family history of such. Role of electrophysiologic testing is currently unclear and is the subject of onging study.

Fig. 19
Type 1 Brugada syndrome. Prominent J-point elevation to a coved ST segment, leading to an inverted T-wave in leads V1 and V2.

Patients presenting with syncope and patients resuscitated from arrest should receive an ICD. Best treatment of those diagnosed by ECG changes and family history is unclear, although they do have increased risk of sudden death.

Last full review/revision January 2008 by L. Brent Mitchell, MD

Content last modified January 2008