Malignant Early Repolarization Syndrome Unmasked by Acute Respiratory Distress Syndrome in a Young Adult.

BACKGROUND: Early repolarization syndrome (ERS) is an important cause of idiopathic ventricular fibrillation (VF) in structurally normal hearts and may be exacerbated by systemic stressors. CASE SUMMARY: A previously healthy 24-year-old man presented with out-of-hospital VF arrest. Coronary angiography and cardiac magnetic resonance imaging showed no structural disease. His course was complicated by aspiration pneumonia and acute respiratory distress syndrome. He developed recurrent VF triggered by short-coupled premature ventricular complexes during hypoxemia and hypokalemia. An electrocardiogram demonstrated inferolateral J-point elevation >0.2 mV. Quinidine and isoproterenol suppressed further arrhythmias, and a subcutaneous implantable cardioverter-defibrillator was placed for secondary prevention. He remained arrhythmia-free at follow-up. DISCUSSION: ERS-related repolarization heterogeneity predisposes to VF. Acute respiratory distress syndrome and associated metabolic stress may amplify this arrhythmogenic substrate. TAKE-HOME MESSAGES: ERS should be considered in young patients with unexplained VF. Recognition of triggers, targeted therapy, and implantable cardioverter-defibrillator placement are essential.