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Brugada Syndrome, Emergency Medicine

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Brugada Syndrome, Emergency Medicine

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 mutationsVariable penetranceSCN5A mutations account for 20%
  • Autosomal dominant in 50%
  • Variable penetration
  • >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
  • HPI:Episodes of syncope or near-syncopePalpitationsCardiac arrestConcomitant illness, fever, metabolic, or electrolyte disordersCocaine useTCA and psychotropic drugsNocturnal agonal respirations
  • Family history:History of drowning due to syncope or dysrhythmias while submergedHistory of early and/or sudden cardiac deathKnown relatives with Brugada syndrome
  • 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
  • History of drowning due to syncope or dysrhythmias while submerged
  • History of early and/or sudden cardiac death
  • Known relatives with Brugada syndrome
  • Complete physical exam, with special attention to other causes of syncope or dysrhythmia:Abnormal heart soundsPectus excavatum (normal variant EKG changes)AthletesPacemaker in situ
  • 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

  • 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-V3ST-elevationSometimes 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 lineNegative symmetric T-waveNo clear r"пїЅQRS duration mismatch between V1 and V6
  • Type 2 (saddle back pattern):High r"пїЅ take-off is ≥2 mm with respect to the isoelectric lineFollowed by ST-elevation - convex with respect to the isolectric lineQRS duration mismatch between V1 and V6
  • Right bundle branch block (RBBB) or Incomplete right bundle branch block (IRBBB) with ST-segment elevation in the right precordial leads only
  • ST-elevation
  • Sometimes only in V1 and very rarely in V3
  • Initial ST-elevation ≥2 mm, slowly descending, concave with respect to the isoelectric line
  • Negative symmetric T-wave
  • No clear r"пїЅ
  • QRS duration mismatch between V1 and V6
  • High r"пїЅ 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
  • Serum:Chemistries to rule out underlying electrolyte causes of dysrhythmia or syncopeCardiac biomarkers (troponin, CK-MB) for ischemiaD-dimer in the appropriate population (Wells, PERC) if considering pulmonary embolismCBC for evaluation of syncope
  • 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
  • CXR:Evaluate for cardiomegaly
  • CT-angiogram of the chest:If considering pulmonary embolism as a cause
  • Evaluate for cardiomegaly
  • If considering pulmonary embolism as a cause
  • Electrophysiology labDrug challenge with sodium channel blockers (type 1a and 1c)
  • AICD placementMortality reduced to 0% in this group
  • Drug challenge with sodium channel blockers (type 1a and 1c)
  • Mortality reduced to 0% in this group

Differential Diagnosis

  • Syncope:Primary cardiogenicVasovagalNeurogenicHypovolemiaPregnancy
  • Dysrhythmias:Paroxysmal atrial fibrillationAtrial fibrillation with rapid ventricular responseWolff-Parkinson-White syndromeLown-Ganong-Levine syndromeVentricular tachycardiaMultifocal atrial tachycardiaSpontaneously terminating ventricular fibrillationSymptomatic bradycardiaHigh-grade heart blocksLong QT syndromesOverdose especially TCA
  • EKG mimics:Isolated RBBBAthletesSeptal hypertrophyPectus excavatumArrhythmogenic right ventricular dysplasiaSTEMI
  • Other systemic illness:Electrolyte disturbancesPericarditisMyocarditisMyopericarditisPulmonary embolism
  • Primary cardiogenic
  • Vasovagal
  • Neurogenic
  • Hypovolemia
  • Pregnancy
  • 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
  • Isolated RBBB
  • Athletes
  • Septal hypertrophy
  • Pectus excavatum
  • Arrhythmogenic right ventricular dysplasia
  • STEMI
  • 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 electrolytesCorrect metabolic derangementsAsymptomatic patients' management controversial. Current consensus states EP evaluation but not supported in literature.
  • For electrophysiology evaluation
  • 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

  • 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
  • Hemodynamically stable
  • Asymptomatic
  • Cardiology clearance
  • Appropriate AICD intervention after an eventAfter interrogation of AICD
  • 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"пїЅ in systemic illness, even if resolution of the EKG occurs, the patient should still have EP follow-up

Additional Reading

  • Bay пїЅs de Luna пїЅA, Brugada пїЅJ, Baranchuk пїЅA, et al. Current electrocardiographic criteria for diagnosis of Brugada pattern: A consensus report. J Electrocardiol. 2012;45(5):433-442.
  • Brady пїЅWJ. 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 пїЅP, Brugada пїЅJ. 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 пїЅA, Rogers пїЅRL, Kim пїЅH, et al. The Brugada syndrome. Am J Emerg Med. 2003;21(2):146-151.

Codes

ICD9

ICD10

  • I49.8 Other specified cardiac arrhythmias
  • Q24.8 Other specified congenital malformations of heart

SNOMED

  • 418818005 brugada syndrome (disorder)