What is the best course of action for a patient with Brugada syndrome, post cardiac arrest and Automatic Implantable Cardioverter-Defibrillator (AICD) placement, who is now experiencing frequent syncopal events?

Management of Frequent Syncope in Brugada Syndrome Post-Cardiac Arrest with AICD

This patient requires immediate hospitalization with continuous telemetry monitoring to determine if the syncopal episodes represent ICD malfunction, recurrent ventricular arrhythmias not being appropriately treated, or non-arrhythmic syncope, followed by intensification of therapy with either quinidine or catheter ablation if recurrent ventricular arrhythmias are confirmed. 1, 2, 3

Immediate Assessment and Stabilization

Critical First Steps

• Admit to monitored bed with continuous telemetry to capture rhythm during syncopal events, as syncope in this high-risk population is presumed arrhythmic until proven otherwise 2, 3
• Interrogate the AICD immediately to determine if:
  • Device is delivering appropriate shocks for ventricular arrhythmias (indicating breakthrough arrhythmias)
  • Device is malfunctioning or has inappropriate settings
  • Syncope occurs without arrhythmia detection (suggesting non-arrhythmic etiology) 1, 2

Environmental and Medication Review

• Check temperature and treat any fever aggressively with antipyretics, as fever can acutely precipitate ventricular fibrillation in Brugada syndrome 1, 4, 3
• Review and discontinue all potentially proarrhythmic medications including sodium channel blockers, QT-prolonging drugs, psychotropic agents, anesthetic agents, and cocaine 1, 4, 3
• Counsel on lifestyle modifications: avoid excessive alcohol intake and large meals, both of which can trigger arrhythmias 1, 4, 3

Risk Stratification Based on AICD Interrogation

If AICD Shows Recurrent Appropriate Shocks for Polymorphic VT/VF

This represents electrical storm requiring intensification of therapy. The 2017 ACC/AHA/HRS guidelines provide a Class I recommendation for either quinidine or catheter ablation in this scenario. 1

Option 1: Quinidine Therapy (Class I Recommendation)

• Quinidine is recommended as first-line intensification therapy for patients experiencing recurrent ICD shocks 1, 4
• Quinidine reduces ventricular fibrillation inducibility and has demonstrated efficacy in preventing electrical storms 1, 4
• This is particularly valuable as it addresses the underlying arrhythmic substrate rather than just treating episodes after they occur 4

Option 2: Catheter Ablation (Class I Recommendation)

• Epicardial catheter ablation of the right ventricular outflow tract is recommended for patients with recurrent ICD shocks 1, 4
• Recent systematic review data shows catheter ablation results in non-inducibility of ventricular arrhythmias in 91% of patients and freedom from ventricular arrhythmias in 87% during mean follow-up of 30.7 months 5
• The incidence of ventricular arrhythmias during follow-up was significantly lower in the ablation cohort compared to ICD-only therapy (OR = 0.03) 5
• Ablation may be considered as an adjunctive therapy to ICD rather than replacement, particularly in patients with high burden of ventricular arrhythmias 5

If AICD Shows No Arrhythmias During Syncopal Events

This suggests non-arrhythmic syncope, which is common even in high-risk Brugada patients. 1, 6

• The mechanism may be vasovagal syncope, bradycardia (AV block or sinus bradycardia), or other non-cardiac causes 6
• In one study of Brugada patients with implantable loop recorders, 50% of syncopal episodes were due to bradycardia, and vasovagal syncope was common, with no ventricular arrhythmias detected during symptomatic events 6
• Consider implantable loop recorder data or extended monitoring if AICD memory is insufficient to capture events 6
• If bradycardia is documented, pacemaker programming adjustments or addition of pacing capability may be warranted 6

Important Caveats and Pitfalls

Understanding the Heterogeneity of Syncope in Brugada Syndrome

• Not all syncope in Brugada syndrome is arrhythmic, even in post-cardiac arrest patients 1, 6
• The 2009 ESC guidelines note that syncope mechanisms may be heterogeneous, being caused by life-threatening arrhythmias in some but being of more benign origin (reflex syncope) in many others 1
• One study found that none of 31 Brugada patients with syncope received appropriate ICD shocks during 39 months follow-up, with appropriate therapy limited to cardiac arrest survivors 1

Balancing Risks and Benefits

• While this patient's annual arrhythmic event rate is elevated at approximately 3.2% (compared to 13.5% in cardiac arrest survivors and 1% in asymptomatic patients), the presence of an AICD already provides protection against sudden death 1, 4, 3
• The goal is to reduce ICD shocks and improve quality of life, not just prevent death, as the device is already in place 1
• Recurrent ICD shocks themselves carry morbidity including psychological trauma, device complications, and reduced quality of life 1

Genetic Counseling Considerations

• Initiate family screening with genetic counseling (Class IIb recommendation), as first-degree relatives may be at risk 1, 3
• SCN5A mutations account for 20-30% of cases, though negative genetic testing does not exclude diagnosis 3

Algorithmic Approach to Decision-Making

1. Interrogate AICD → Determine if shocks are occurring
2. If appropriate shocks present → Electrical storm → Start quinidine OR perform catheter ablation (both Class I) 1
3. If no arrhythmias detected → Investigate non-arrhythmic causes → Consider bradycardia treatment or reassurance if vasovagal 6
4. Regardless of etiology → Review medications, treat fever aggressively, counsel on lifestyle modifications 1, 4, 3
5. Arrange electrophysiology follow-up for ongoing management and family screening 2, 3