Clinical Notes : Cardiovascular Disease

115. Brugada Syndrome

Brugada Syndrome

 

Definitions

Brugada syndrome is a disorder characterized by sudden death associated with one of several ECG patterns characterized by incomplete right bundle-branch block and ST-segment elevations in the anterior precordial leads.

Three types of ST-segment elevation in Brugada syndrome, as shown in the precordial leads on ECG in the same patient at different times.

Left panel shows a type 1 ECG pattern with pronounced elevation of the J point (arrow), a coved-type ST segment, and an inverted T wave in V1 and V2.

The middle panel illustrates a type 2 pattern with a saddleback ST-segment elevated by >1 mm.

The right panel shows a type 3 pattern in which the ST segment is elevated <1 mm. 

 

Epidemiology

 

Brugada syndrome is genetically determined and has an autosomal dominant pattern of transmission in about 50% of familial cases (see Etiology).

The typical patient with Brugada syndrome is young, male, and otherwise healthy, with normal general medical and cardiovascular physical examinations.

Brugada syndrome is 8-10 times more prevalent in men than in women, 

About 5% of survivors of cardiac arrest have no clinically identified cardiac abnormality. About half of these cases are thought to be due to Brugada syndrome. (1)

Brugada syndrome is most common in people from Asia.

n parts of Asia (eg, the Philippines, Thailand, Japan), Brugada syndrome seems to be the most common cause of natural death in men younger than 50 years. It is known as Lai Tai (Thailand), Bangungot (Philippines), and Pokkuri (Japan). In Northeast Thailand, the mortality rate from Lai Tai is approximately 30 cases per 100,000 population per year. (2)

The mean age of patients who die suddenly is 41 years. (3)

Signs and Symptoms

 

Signs and symptoms in patients with Brugada syndrome may include the following:

  • Syncope and cardiac arrest: Most common clinical manifestations; in many cases, cardiac arrest occurs during sleep or rest

  • Nightmares or thrashing at night

  • Asymptomatic, but routine ECG shows ST-segment elevation in leads V1-V3

  • Associated atrial fibrillation (20%) (4)

  • Fever: Often reported to trigger or exacerbate clinical manifestations

The lack of a prodrome has been reported to be more common in patients with ventricular fibrillation documented as the cause of syncope in patients with Brugada syndrome. (5)

 
 

Diagnosis

Most patients with Brugada syndrome have a normal physical examination.

However, such an examination is necessary to exclude other potential cardiac causes of syncope or cardiac arrest in an otherwise healthy patient (eg, heart murmurs from hypertrophic cardiomyopathy or from a valvular or septal defect).

Investigations

  • In OOH setting

    • 12-lead ECG in all patients with syncope

  • In A+E setting

    • In patients with suspected Brugada syndrome, consider the following studies:

      • 12-lead ECG in all patients with syncope

      • Drug challenge with a sodium channel blocker in patients with syncope without an obvious cause

      • Electrophysiologic study to determine the inducibility of arrhythmias for risk stratification

    • Laboratory tests that may aid in the diagnosis of Brugada syndrome include the following:

      • Serum potassium and calcium levels: In patients presenting with ST-segment elevation in the right precordial leads

      • Potassium and calcium levels: ECG patterns in patients with hypercalcemia and hyperkalemia similar to that of Brugada syndrome

      • CK-MB and troponin levels: In patients with symptoms compatible with an acute coronary syndrome

      • Genetic testing for a mutation in SCN5A

    • Further testing may be indicated to exclude other diagnostic possibilities.

    • Imaging studies

      • Perform echocardiography and/or MRI, primarily to exclude arrhythmogenic right ventricular cardiomyopathy, as well as to assess for other potential causes of arrhythmias.

 
 

Management

In OOH setting, refer all suspected cases of Brugada Syndrome to A+E.

To date, the only treatment that has proven effective in treating ventricular tachycardia and fibrillation and preventing sudden death in patients with Brugada syndrome is implantation of an automatic implantable cardiac defibrillator (ICD).

No pharmacologic therapy has been proven to reduce the occurrence of ventricular arrhythmias or sudden death; however, theoretically, drugs that counteract the ionic current imbalance in Brugada syndrome could be used to treat it.

 
journals.png

1. Alings M, Wilde A.

"Brugada" syndrome: clinical data and suggested pathophysiological mechanism. 

Circulation. 1999 Feb 9. 99(5):666-73

View/Access

2. Nademanee K, Veerakul G, Nimmannit S, Chaowakul V, Bhuripanyo K, Likittanasombat K, et al.

Arrhythmogenic marker for the sudden unexplained death syndrome in Thai men. 

Circulation. 1997 Oct 21. 96(8):2595-600.

View/Access

3. Antzelevitch C, Brugada P, Brugada J, Brugada R.

Brugada syndrome: from cell to bedside. 

Curr Probl Cardiol. 2005 Jan. 30(1):9-54

View/Access

4. Bordachar P, Reuter S, Garrigue S, et al.

Incidence, clinical implications and prognosis of atrial arrhythmias in Brugada syndrome. 

Eur Heart J. 2004 May. 25(10):879-84

View/Access

5. Take Y, Morita H, Toh N, Nishii N, Nagase S, Nakamura K, et al.

Identification of high-risk syncope related to ventricular fibrillation in patients with Brugada syndrome. 

Heart Rhythm. 2012 May. 9(5):752-9.

View/Access

Ireland notes.png
 

CPD Quiz and Certificate

This activity attracts 1,0 CPD point

Scroll down the box above to view its entire content

All users who successfully complete the quiz are e-mailed a copy of their personalised CPD certificate.