Brugada Syndrome

Background

Brugada Syndrome is a rare inherited cardiac arrhythmia syndrome that is characteristed by a ‘coved-shaped’ atypical right bundle branchpattern on a 12-lead ECG (Type-1 Brugada pattern ECG) and is associated with ventricular arrhythmias and sudden cardiac death.  Brugada Syndrome is reported to be responsible for 4% of all sudden deaths and 20% of sudden deaths in those without structural heart disease.

It is the leading inherited cardiac cause of sudden death in subjects under 40 years.  However, a family history is present in only about 20-30% of patients. The ECG changes of Brugada Syndrome are dynamic and can vary spontaneously making it difficult to assess its exact incidence in the general population  but it’s prevalence is reported to be about 1 in 2000.

Many people who have Brugada Syndrome don’t have any symptoms, and so they’re unaware of their condition. For some, however, Brugada syndrome can cause dangerous irregular heart rhythms that can cause fainting or sudden cardiac arrest. The abnormal Brugada ECG pattern can be induced by a variety of cardiac and non-cardiac medications so avoidance of these medications is paramount to the treatment of this disease.

Treatment of Brugada Syndrome is involves a combination of preventive measures such as avoiding aggravating medications, reducing fever and sometimes when necessary, using a medical device called an implantable cardioverter-defibrillator (ICD).

Symptoms

Patients with Brugada Syndrome may present with syncope due to dangerous heart rhythms from the bottom chamber of the heart (Polymorphic Ventricular Tachycardia or  and Ventricular Fibrillation) or resuscitated sudden death in the third or fourth decade of life. Symptoms typically occur at night, or at rest during the day, and are due to polymorphic VT or ventricular fibrillation (VF). Many people who have Brugada Syndrome are undiagnosed because the condition often hasn’t caused any noticeable signs or symptoms.

The diagnosis of Brugada Syndrome may also be made on family screening of patients with Brugada Syndrome or from a routine ECG. More than 80% of adult patients are males but in children there is an equal male to female ratio. Clinical presentation is predominantly after adolescence with a peak in the third and fourth decade of life. In cases of sudden cardiac deaths Brugada Syndrome may be under-diagnosed as ECG prior to death is generally not available and even if an ECG has been recorded ECG changes, being variable, may not be diagnostic.

The most important sign is the presence of the diagnostic Type-1 Brugada pattern on an electrocardiogram, or ECG. Pattern, only detected on an ECG. Only Type 1 ECG pattern is diagnostic of Brugada Syndrome. Type 2 and 3 patterns are not diagnostic of Brugada Syndrome and distinction from a normal variant can be difficult and pharmacological provocation test may be required if the diagnosis of Brugada Syndrome is suspected.

It’s possible to have a Brugada pattern ECG without having Brugada Syndrome. However, signs and symptoms that could mean you may have Brugada Syndrome include:

1. Fainting (syncope)
2. Irregular heartbeats or palpitations
3. Stopped heartbeat (sudden cardiac arrest)

Causes

Brugada syndrome is a heart rhythm disorder. Each beat of the heart is triggered by an electrical impulse generated by special cells in the right upper chamber of your heart. Tiny pores, called channels, on each of these cells direct this electrical activity, which makes your heart beat. In Brugada syndrome, a defect in these channels can cause the  heart to beat abnormally. The most common defect is an abnormality in a cardiac sodium channel.

Brugada Syndrome is usually inherited, but it may also result from a structural abnormality in the heart, imbalances in chemicals that help transmit electrical signals through the body (electrolytes), or the effects of certain prescription medications or cocaine use. Brugada syndrome is usually diagnosed in adolescents and adults. It may be  diagnosed in young children where it is frequently precipitated by fever.

Risk factors

Associated risk factors for Brugada Syndrome include:

• Family history of Brugada syndrome. If other family members have had Brugada syndrome, there is an increased risk of having the condition.
• Being male. Adult men are more frequently diagnosed than are women. In young children and adolescents, however, boys and girls are diagnosed at about the same rate.
• Race. Brugada syndrome occurs more frequently in Asians than in other races.
• Fever. While having a fever doesn’t bring on Brugada syndrome itself, fever can increase the risk of fainting or other complications of Brugada syndrome, especially in children.

Complications

The most serious complication of Brugada syndrome is sudden cardiac arrest. Sudden cardiac arrest is the sudden, unexpected loss of heart function, breathing and consciousness. It’s a medical emergency. If not treated immediately, the condition is fatal, resulting in sudden cardiac death. With fast, appropriate medical care, survival is possible. Administering cardiopulmonary resuscitation (CPR) — or even just rapid compressions to the chest — can improve the chances of survival until emergency personnel arrive.

Sudden fainting (syncope) is another complication of Brugada syndrome. If you have Brugada syndrome and you faint, seek emergency medical attention.

Tests

Aside from a typical physical examination and listening to your heart with a stethoscope, tests to see if you have Brugada Syndrome may include:

• Electrocardiogram (ECG) with IV Drug Challenge. In this noninvasive test, a technician will place electrical stickers on your chest that record the electrical impulses that make your heart beat. An ECG records these electrical signals and can help your doctor detect irregularities in your heart’s rhythm and structure. Brugada pattern may be intermittent and  a single ECG by itself may not always detect the diagnostic Type-1 Brugada pattern ECG. Your doctor may give you a medication that induces or unmasks the diagnostic Type-1 Brugada pattern ECG. The medication we typically use is called Flecainide and is slowly injected via an intravenous (IV) line.

• Genetic testing. While genetic testing isn’t required to diagnose Brugada Syndrome, your doctor may recommend genetic testing for you and other family members if you’re diagnosed with Brugada Syndrome. The available genetic tests for Brugada are reliable in about 40% of Brugada patients.
• Electrophysiology (EP) Study Your doctor may also recommend an EP study to determine if your symptoms of palpitations are due to Brugada Syndrome or another heart rhythm problem.

Treatment

The diagnosis of Brugada Syndrome can only be considered when a diagnostic Type-1 Brugada pattern ECG occurs spontaneously or following drug provocation. The diagnosis is further confirmed when the ECG pattern occurs   in conjunction with one of the following:

• Documented Ventricular Fibrillation (VF), polymorphic VT
• A family history of sudden cardiac death at <45 years
• A diagnostic Type-1 Brugada pattern ECG in family members
• Inducibility of VT during an electrical study
• Syncope or nocturnal agonal respiration (attributed to self-terminating polymorphic VT or VF).

General Principles of Management

Treatment of Brugada Syndrome depends on the risk of an abnormal heartbeat (arrhythmia) for that particular individual. Those considered at high risk have:

•   A family history of sudden cardiac death
•   A personal history of serious heart rhythm problems
•   A personal history of severe fainting spells

High Risk and Symptomatic Brugada Syndrome Patients

Implantable cardioverter-defibrillator (ICD).For high-risk individuals and symptomatic Brugada Syndrome patients, treatment may involve an Implantable Cardioverter-Defibrillator (ICD). An ICD is a small device continuously monitors your heart rhythm and delivers electrical shocks when needed to control abnormal heartbeats. The guidelines recommends ICD implantation in Brugada Syndrome patients who have survived cardiac arrest or have a history of syncope and documented ventricular arrhythmias.

There’s a small risk of complications from having an ICD implanted. People who have an ICD implanted as a treatment for Brugada syndrome have reported receiving shocks from their ICD even when their heartbeat was regular. These are called inappropriate shocks. This may be because many people who receive an ICD as a treatment for Brugada Syndrome are young, and may receive shocks when their heart rates increase during normal stresses, such as exercise.

Sometimes an inappropriate shock is delivered for another fast heart rhythm such as Atrial Fibrillation or an unrelated heart rhythm problem such as Supraventricular Tachycardia (SVT). Atrial Fibrillation occurs in about 20% of patients with Brugada Syndrome. Your doctor will program your ICD to reduce this risk. If you have an ICD implanted as part of your Brugada syndrome treatment, talk to your doctor about ways to avoid inappropriate shocks.

Drug Treatment

A drug called Quinidine is used in Brugada Syndrome patients who have repeated ICD shocks or an ‘arrhythmic storm’ .  Intravenous Isoprenaline (a form of adrenaline) is also helpful in the emergency treatment of arrhythmic storms in Brugada Syndrome.

Asymptomatic Individuals with Brugada Syndrome

As the changes of Brugada Syndrome on ECG are unmasked by a febrile states, aggressive treatment of all febrile episodes is recommended with antipyretics like aspirin and paracetamol and cold sponges. Hypokalemia, large carbohydrate meals and alcohol and very hot baths have also been incriminated and should be avoided.

Drugs that can cause Brugada-like changes on the ECG are best avoided and include: Class 1antiarrhythmic drugs like flecainide, beta and alpha adrenergic blockers, channel blockers like verapamil, diltiazem, nifedipine, nitrates, potassium channel openers like nicorandil, tricyclic and tetracyclic antidepressants, phenothiazines and antidepressants like fluoxetine. Alcohol and cocaine can cause dangerous heart rhythms in patients with Brugada Syndrome. A website www.brugadadrugs.org gives a list of drugs to be avoided, preferably avoided and potential antiarrhythmic drugs in Brugada Syndrome.

Continued medical checkups. If you have Brugada syndrome, it’s a good idea to regularly check in with your doctor to make sure you’re properly managing your heart condition. Regular checkups can help your doctor decide if you need to change your treatment, and may help catch new problems early, if they occur.