Brugada Syndrome

Mamata raiMsc. Nursing 2nd year

AIIMS

Introduction

Brugada syndrome is a  genetic disease that is characterized by sudden death associated with abnormal electrocardiogram disorder.

One of several ECG patterns characterized by are incomplete right bundle-branch block and ST-segment elevations in the anterior precordial leads(V1-V3) without ischemia.

Introduction

The cause of syncope and sudden death in Brugada syndrome are caused by fast polymorphic ventricular tachycardias or ventricular fibrillation. These arrhythmias appear with no warning.

According to clinical reports, sudden death in people with Brugada syndrome most often happens during sleep.

Introduction Monomorphic VT rarely occurs , especially in

patients taking antiarrhythmic drugs .

Supraventricular tachycardias are more prevalent in Brugada syndrome .

An estimated 80% of subjects with documented VT/VF has a history of syncope , caused by self-terminating episodes.

Epidemiology

In parts of Asia Brugada syndrome seems to be the most common cause of natural death in men <50 years.

It is approximately 30 cases per 100,000 population per year.

And 8-10 times more prevalent in men than in women, although the probability of having a mutated gene does not differ by sex.

Risk group

Etiology

1. The majority of patients affected by Brugada syndrome are not found to have known genetic mutations to explain the disease. 

2. Approximately 20% due to alterations in the SCN5A gene(encodes the cardiac sodium channel)

3. Mutations in the genes  Glycerol-3-phosphate dehydrogenase 1-like gene(GPD1-L) and SCN1B

Pathophysiology

Approximately 10-30% of the cases of Brugada syndrome have been shown to be associated with mutations in a gene that encodes for a sodium ion channel in the cell membranes myocytes this is often referred to as a sodium channelopathy.

Pathophysiology(SCN5A)

Signs and symptoms

1. Syncope and cardiac arrest: Mostly cardiac arrest occurs during sleep or rest

2. Nightmares or thrashing at night3. Asymptomatic, but routine ECG shows ST-

segment elevation in leads V1-V34. Associated atrial fibrillation (20%)  5. Fever: Often reported to trigger or exacerbate

clinical manifestations.

TYPES

Brugada syndrome has three different ECG patterns1. Type 1 has a coved type ST elevation with at least

2 mm (0.2 mV) J-point elevation and a gradually descending ST segment followed by a negative T-wave.

2. Type 2 has a saddle-back pattern with a least 2 mm J-point elevation and at least 1 mm ST elevation with a positive or biphasic T-wave. Type 2 pattern can occasionally be seen in healthy subjects.

3. Type 3 has either a coved (type 1 like) or a saddle-back (type 2 like) pattern, with less than 2 mm J-point elevation and less than 1 mm ST elevation.

Diagnosis

12-lead ECG Drug challenge with a sodium channel blocker.Electrophysiologic study.Laboratory testsSerum potassium and calcium levels: ECG patterns

in patients with hypercalcemia and hyperkalemia similar to that of Brugada syndrome

CK-MB and troponin levels: defrentiate ACSGenetic testing for a mutation in SCN5A

Long QT syndrome

It is a congenital disorder characterized by a prolongation of the QT interval on ECG and a propensity to ventricular tachyarrhythmias, which may lead to syncope, cardiac arrest, or sudden death.

QT interval 0.36–0.44s (9–11 small squares).

How to find out VT in RBBB or LBBB ?

If RBBB pattern, then VT is present in the following situations:

A monophasic R or biphasic qR complex in V1.If an RSR’ pattern is present in V1.A rS complex in lead V6 favors VT

If LBBB pattern, then VT is present in the following situations:

The presence of any Q or QS wave in lead V6 favors VT

A wide R wave in lead V1 or V2 of 0.04s or more favors VT

Slurred or notched downstroke of the S wave in V1 or V2 favors VT

Differential diagnosis of ST-segment elevation

1. Atypical right bundle-branch block2. Left ventricular hypertrophy3. Early repolarization4. Acute pericarditis5. Acute myocardial ischemia or infarction6. Pulmonary embolism7. Dissecting aortic aneurysm8. Arrhythmogenic right ventricular dysplasia and/or

cardiomyopathy9. Various abnormalities of the central and autonomic

nervous systems10. Overdose of a antidepressant11. Thiamine deficiency Hypercalcemia12. Hyperkalemia13. Effects of athletic training

Management

There is no exact treatment modality that reliably and totally prevents ventricular fibrillation from occurring in this syndrome

treatment lies in termination of this lethal arrhythmia before it causes death.

 Implantable cardioverter-defibrillator(ICD) is inserted , which continuously monitors the heart rhythm and will shock the wearer if ventricular fibrillation is sensed.

Quinidine , a pharmaceutical agent that acts as a class I antiarrhythmic agent is used.

Quinidine Sulfate

Test Dose: 200 mg PO quinidine sulfate several hr before full dosage

AFib: 300-400 mg PO q6hrPSVT: 400-600 mg PO q2-3hr until paroxysm

terminatedAtrial/Ventr Premature Contractions: 200-300

mg PO TID/QIDMaint: 200-400 mg PONo more than 3-4 g/d

AICD

The automatic implantable cardioverter-defibrillator (AICD) is a device designed to monitor the heartbeat. This device can deliver an electrical impulse or shock to the heart when it senses a life threatening change in the heart’s rhythm like sustained ventricular tachycardia or fibrillation

Complication

1. VT2. VF 3. Cardiac arrest 4. death

Prognosis

An estimated 4% of all sudden deaths and at least 20% of sudden deaths in patients with structurally normal hearts are due to this syndrome.

Conclusion

Bikash is 13 yrs male student diagnosed with brugada syndrome type 2, managed with AICD dual chamber is discharged in stable condition with uneventful hospitalization period.