Background: A 25-year-old woman experienced three episodes of syncope over the course of 2 years. The attacks all occurred just after she had sat down, and two were accompanied by convulsions. She had no obvious prodromes and no personal or family history of cardiovascular disease.
Investigations: Electrocardiography, chest radiography, echocardiography, cerebral and cardiac MRI, electroencephalography, 24 h Holter monitoring, electrophysiological study with drug provocation testing and heart-rate variability analysis.
Diagnosis: Vagally mediated ventricular fibrillation initiated by premature ventricular complexes arising from the right ventricular outflow tract.
Management: Catheter ablation was performed at the right ventricular outflow tract and an implantable cardioverter-defibrillator was fitted.