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. See the image below.

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. According to a consensus report (Antzelevitch, 2005), the type 1 ECG pattern is diagnostic of Brugada syndrome. Modified from Wilde, 2002. Image courtesy of Richard Nunez, MD, and EMedHome.com (http://www.emedhome.com/). View Media Gallery

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%) [1]

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. [2]

See Presentation for more detail.

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).

Testing

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.

See Workup for more detail.

Management

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). Radiofrequency catheter ablation has been recently reported as an effective new treatment. [3, 4, 5, 6, 7]

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. For example, quinidine, which blocks the calcium-independent transient outward potassium current (Ito), has been shown to normalize the ECG pattern in patients with Brugada syndrome. [8] However, quinidine also blocks sodium (Na) currents, which could have contrary effects.

See Treatment and Medication for more detail.