Spontaneous Conversion of Transient VFib in Brugada Syndrome
Ventricular fibrillation in Brugada syndrome does NOT spontaneously convert to normal rhythm—it requires defibrillation or ICD shock to terminate, making this a uniformly fatal arrhythmia without intervention.
Critical Understanding of VFib in Brugada Syndrome
The evidence clearly demonstrates that when VFib occurs in Brugada syndrome patients, it necessitates electrical termination:
ICD data from asymptomatic Brugada patients shows 7-13% received appropriate ICD shocks over long-term follow-up, indicating these were life-threatening arrhythmias requiring device intervention 1.
One death was documented from inappropriate shock-induced ventricular fibrillation in an ICD patient, demonstrating that once VFib is triggered, it does not self-terminate 1.
Spontaneous VFib episodes documented by ICDs were all terminated by device therapy, with no evidence of self-termination in the 46 episodes analyzed across multiple patients 2.
Mechanism Explains Why Spontaneous Conversion Does Not Occur
The pathophysiology of Brugada syndrome VFib makes spontaneous conversion extremely unlikely:
VFib is triggered by specific premature ventricular contractions (PVCs) with short coupling intervals (388 ± 28 ms), and once initiated, the arrhythmia is sustained 2.
The same specific PVC repeatedly triggers VFib in individual patients, suggesting a fixed substrate that maintains the arrhythmia once initiated 2.
The electrical heterogeneity in right ventricular epicardium creates a phase 2 reentrant mechanism that perpetuates VT/VF once triggered 3.
Clinical Evidence from Natural History Studies
Registry data confirms the lethal nature of untreated VFib:
Patients with inducible ventricular arrhythmias had a 28% incidence of spontaneous ventricular fibrillation in early observational studies, and these events required intervention 1.
The annual event rate for VA or ICD shock in high-risk patients was 4.5%, with all documented events requiring device therapy for termination 1.
Brugada syndrome is second only to automobile accidents as a cause of death among young adults in some countries, precisely because VFib does not self-terminate 4.
Practical Clinical Implications
This understanding has critical management implications:
ICD implantation is mandatory (Class I recommendation) for survivors of aborted cardiac arrest, because the first VFib episode would have been fatal without intervention 5.
Asymptomatic patients with spontaneous type 1 ECG and syncope should receive ICD (Class IIa), as their first VFib episode may be fatal 5.
Patients must avoid all triggers (fever, certain medications, excessive alcohol) because any VFib episode will require defibrillation 5.
Fever must be aggressively treated with antipyretics as it can acutely precipitate cardiac arrest that will not self-terminate 5.
Common Pitfall to Avoid
Do not confuse transient ECG changes with transient arrhythmias: The type 1 Brugada ECG pattern is dynamic and may come and go 5, but this does NOT mean that VFib episodes are self-limited. The ECG pattern fluctuates, but VFib remains uniformly fatal without intervention.