Basics
Description
- Inherited heart disease due to mutations of cardiac Na+ channels without structural abnormalities
- Very high risk of sudden cardiac death in the form of ventricular fibrillation
- 2-yr mortality ~30%
- Suspected in 40-60% of what was previously known as idiopathic ventricular fibrillation
- Higher prevalence in men of Southeast Asian descent, but all ages, genders, races can be affected
Etiology
- Inherited:
- Autosomal dominant in 50%
- Variable penetration
- Cardiac Na+ channel:
- >70 described mutations
- Variable penetrance
- SCN5A mutations account for 20%
Diagnosis
Signs and Symptoms
- Most commonly presents as episodes of sudden death (in ventricular fibrillation) or as syncope or near-syncope in self-terminating episodes of polymorphic ventricular tachycardia
History
- HPI:
- Episodes of syncope or near-syncope
- Palpitations
- Cardiac arrest
- Concomitant illness, fever, metabolic, or electrolyte disorders
- Cocaine use
- TCA and psychotropic drugs
- Nocturnal agonal respirations
- Family history:
- History of drowning due to syncope or dysrhythmias while submerged
- History of early and/or sudden cardiac death
- Known relatives with Brugada syndrome
Physical Exam
- Complete physical exam, with special attention to other causes of syncope or dysrhythmia:
- Abnormal heart sounds
- Pectus excavatum (normal variant EKG changes)
- Athletes
- Pacemaker in situ
Essential Workup
- A 12-lead EKG is imperative
- Detailed HPI and family history
- Toxicology screen
Diagnosis Tests & Interpretation
EKG Diagnostic Criteria
- Basic:
- Right bundle branch block (RBBB) or Incomplete right bundle branch block (IRBBB) with ST-segment elevation in the right precordial leads only
- Morphology of QRS-T in V1-V3
- ST-elevation
- Sometimes only in V1 and very rarely in V3
- Type 1 (coved pattern):
- Initial ST-elevation ≥2 mm, slowly descending, concave with respect to the isoelectric line
- Negative symmetric T-wave
- No clear r"�
- QRS duration mismatch between V1 and V6
- Type 2 (saddle back pattern):
- High r"� take-off is ≥2 mm with respect to the isoelectric line
- Followed by ST-elevation - convex with respect to the isolectric line
- QRS duration mismatch between V1 and V6
Lab
- Serum:
- Chemistries to rule out underlying electrolyte causes of dysrhythmia or syncope
- Cardiac biomarkers (troponin, CK-MB) for ischemia
- D-dimer in the appropriate population (Wells, PERC) if considering pulmonary embolism
- CBC for evaluation of syncope
Imaging
- CXR:
- Evaluate for cardiomegaly
- CT-angiogram of the chest:
- If considering pulmonary embolism as a cause
Diagnostic Procedures/Surgery
- Electrophysiology lab
- Drug challenge with sodium channel blockers (type 1a and 1c)
- AICD placement
- Mortality reduced to 0% in this group
Differential Diagnosis
- Syncope:
- Primary cardiogenic
- Vasovagal
- Neurogenic
- Hypovolemia
- Pregnancy
- Dysrhythmias:
- Paroxysmal atrial fibrillation
- Atrial fibrillation with rapid ventricular response
- Wolff-Parkinson-White syndrome
- Lown-Ganong-Levine syndrome
- Ventricular tachycardia
- Multifocal atrial tachycardia
- Spontaneously terminating ventricular fibrillation
- Symptomatic bradycardia
- High-grade heart blocks
- Long QT syndromes
- Overdose especially TCA
- EKG mimics:
- Isolated RBBB
- Athletes
- Septal hypertrophy
- Pectus excavatum
- Arrhythmogenic right ventricular dysplasia
- STEMI
- Other systemic illness:
- Electrolyte disturbances
- Pericarditis
- Myocarditis
- Myopericarditis
- Pulmonary embolism
Treatment
Pre-Hospital
- Airway, breathing, and circulation management
- ACLS protocol for arrest/dysrhythmias
Initial Stabilization/Therapy
- Airway, breathing, and circulation management
- Start or continue ACLS algorithms
Ed Treatment/Procedures
- Cardiac monitoring at all times
- Cardiology consult:
- For electrophysiology evaluation
- Defibrillator/pacing pads
- Correct underlying disease processes:
- Replete electrolytes
- Correct metabolic derangements
- Asymptomatic patients' management controversial. Current consensus states EP evaluation but not supported in literature.
Medication
- ACLS medications per protocol
- Antiarrhythmics usually not helpful
- PALS/defibrillation
- Appropriate weight-based medication and energy (joule) adjustments
Follow-Up
Disposition
Admission Criteria
- EKG findings concerning for Brugada in the appropriate clinical setting
- Unexplained syncope
- Inability to obtain rapid cardiology follow-up
- Ongoing dysrhythmias even if they are spontaneously terminating
Discharge Criteria
- Hemodynamically stable
- Asymptomatic
- Cardiology clearance
- Appropriate AICD intervention after an event
- After interrogation of AICD
Follow-Up Recommendations
- All patients with concerning EKG findings and history should be referred to EP for additional evaluation
Pearls and Pitfalls
- Consider in any episodes of sudden cardiac death or syncope, especially in the setting of family history of the same
- The EKG is diagnostic showing RBBB or IRBBB with ST-segment elevation in the right precordial leads only
- Beware of EKG mimics which can have similar presentation - typically mimics will have concordant QRS duration in V1 and V6 whereas Brugada QRS changes should be isolated to V1-V3
- Have a low threshold for cardiology consultation given high risk of death
- AICD implantation is definitive treatment, almost eliminating risk of sudden cardiac death
- Antiarrhythmic agents have not been found to be helpful
- The Brugada pattern may be "unmasked"� in systemic illness, even if resolution of the EKG occurs, the patient should still have EP follow-up
Additional Reading
- Bay �s de Luna �A, Brugada �J, Baranchuk �A, et al. Current electrocardiographic criteria for diagnosis of Brugada pattern: A consensus report. J Electrocardiol. 2012;45(5):433-442.
- Brady �WJ. ST segment and T wave abnormalities not caused by acute coronary syndromes. Emerg Med Clin North Am. 2006;24(1):91-111, vi. Review.
- Brugada �P, Brugada �J. Right bundle branch block, persistent ST segment elevation and sudden cardiac death: A distinct clinical and electrocardiographic syndrome. J Am Coll Cardiol. 1992;20:1391-1396.
- Mattu �A, Rogers �RL, Kim �H, et al. The Brugada syndrome. Am J Emerg Med. 2003;21(2):146-151.
Codes
ICD9
746.89 Other specified congenital anomalies of heart �
ICD10
- I49.8 Other specified cardiac arrhythmias
- Q24.8 Other specified congenital malformations of heart
SNOMED
- 418818005 brugada syndrome (disorder)