Diagnostic Evolution From Channelopathy to Idiopathic Ventricular Fibrillation After Aborted Sudden Cardiac Death

Idiopathic ventricular fibrillation (IVF) is a life-threatening condition with no identifiable structural or metabolic etiology. It is a diagnosis of exclusion and accounts for a significant proportion of unexplained sudden cardiac death (SCD) in young healthy individuals.

In a 23-year-old woman initially experiencing seizure-like activity, long QT syndrome was later diagnosed. Following placement of an implantable cardioverter-defibrillator, subsequent evaluation, including cardiac magnetic resonance, negative 51-gene arrhythmia panel, and subcutaneous cardiac monitor implantable loop recorder, confirmed the spontaneous episode of ventricular fibrillation. In the absence of a persistent long QT syndrome phenotype, the findings were most consistent with IVF.

This case underscores the importance of systematic reassessment and high clinical suspicion to establish IVF and guide timely management.

IVF is a diagnosis of exclusion requiring comprehensive evaluation and management with implantable defibrillators and antiarrhythmic therapy for preventing recurrent episodes.