Most Common Rhythm in Brugada Syndrome with Non-Cardiac Arrest Arrhythmias
The most common arrhythmias in Brugada syndrome patients experiencing episodic events that do not result in cardiac arrest are polymorphic ventricular tachycardia (VT), followed by supraventricular arrhythmias and conduction disorders.
Primary Arrhythmic Pattern
The guidelines clearly establish that polymorphic VT is the characteristic ventricular arrhythmia in Brugada syndrome 1, 2. When patients with Brugada syndrome experience symptomatic ventricular arrhythmias (VA) that don't progress to cardiac arrest, these typically manifest as:
- Polymorphic VT - the hallmark rhythm disturbance
- Episodes may be self-terminating (nonsustained) rather than progressing to ventricular fibrillation
- These arrhythmias are specifically mentioned in guideline recommendations for ICD shock management, where quinidine or catheter ablation is recommended for recurrent polymorphic VT 1, 2
Additional Rhythm Findings from Continuous Monitoring
Recent evidence from implantable loop recorder (ILR) studies reveals a more nuanced picture of rhythm disturbances in symptomatic Brugada patients 3:
- Supraventricular arrhythmias are frequently recorded
- Conduction disorders are common
- Ventricular arrhythmias (usually nonsustained) are actually rarely documented on continuous monitoring
- This suggests that many symptomatic episodes attributed to Brugada syndrome may have alternative explanations
Clinical Context and Pitfalls
Critical caveat: The most common presenting symptom in Brugada syndrome is syncope 4, 5, but the actual rhythm during these episodes is often not captured. When rhythm is documented:
- Polymorphic VT remains the characteristic life-threatening arrhythmia
- However, benign arrhythmias or non-arrhythmic causes (neurally mediated syncope) may be more frequently documented than previously recognized 3
- This discrepancy highlights the importance of rhythm documentation rather than assuming all symptoms are from ventricular arrhythmias
The guidelines specifically address polymorphic VT as the target arrhythmia requiring intensified therapy (quinidine or ablation) in patients experiencing recurrent ICD shocks 1, 2, confirming this as the clinically significant rhythm pattern that distinguishes Brugada syndrome from other conditions.