What are the electrocardiogram (ECG) changes associated with Brugada syndrome?

From the Guidelines

Brugada syndrome on ECG is characterized by a distinctive pattern in the right precordial leads, most notably a coved-type ST-segment elevation, which is diagnostic when present as a Type 1 Brugada pattern. This pattern is associated with an increased risk of sudden cardiac death, particularly in young adults without structural heart disease 1. The ECG changes may be intermittent and can be unmasked by sodium channel blocking drugs like flecainide or ajmaline during diagnostic testing.

Key ECG Features

• Coved-type ST-segment elevation (≥2 mm) in leads V1 or V2
• Negative T waves in the right precordial leads
• QRS complex fractionation in a minority of patients
• Type 1 Brugada ECG pattern may be present spontaneously, during fever or vagotonic states, or after medication challenge with sodium channel blockers 1

Diagnostic Considerations

• The use of high electrocardiographic electrode positioning in the second and third interspaces for electrocardiographic recording improves detection of a type 1 Brugada ECG 1
• Asymptomatic patients with a family history of Brugada syndrome may be offered sodium channel blocker challenge for diagnostic evaluation, although a positive test does not require chronic therapy due to a low risk in this setting 1
• In asymptomatic patients with type 1 Brugada electrocardiographic findings, medication challenge does not offer additional diagnostic value 1

From the Research

Brugada Syndrome ECG Changes

• Brugada syndrome is characterized by distinct coved type ST segment elevation in the right-precordial leads on an electrocardiogram (ECG) 2, 3, 4, 5.
• The ECG manifestations of Brugada syndrome are often concealed and may be unmasked or aggravated by sodium channel blockers, a febrile state, vagotonic agents, as well as by tricyclic and tetracyclic antidepressants 2.
• The syndrome is associated with a high risk for sudden cardiac death in young adults, and less frequently in infants and children 2.
• ECG changes in Brugada syndrome include:
  • Coved ST-segment elevation ≥2 mm and a negative T-wave in the right precordial leads 3, 4.
  • Long PQ and QRS intervals, high ST level 6.
• These ECG changes are often intermittent, and may be provoked by fever or sodium channel blocker challenge 3, 4.

Factors Influencing ECG Changes

• Fever can unmask Brugada syndrome on ECG in susceptible individuals 4.
• Sodium channel blockers can unmask or aggravate ECG changes in Brugada syndrome 2, 6.
• Vagotonic agents and tricyclic and tetracyclic antidepressants can also unmask or aggravate ECG changes in Brugada syndrome 2.

Clinical Significance of ECG Changes

• Spontaneous type 1 ECG pattern is associated with future fatal arrhythmic events 6.
• Symptomatic patients and high ST level (V1) ≥0.3 mV after sodium channel blocker test are independent predictors for future fatal arrhythmic events 6.
• Sodium channel blocker-induced ventricular tachyarrhythmias are associated with an increased risk of the development of ventricular tachycardia/ventricular fibrillation events during follow-up in patients with Brugada syndrome 6.