Two-to-one Purkinje-to-myocardium Activation During Ventricular Fibrillation Associated with Hypertrophic Cardiomyopathy.

Key Teaching Points•In hypertrophic cardiomyopathy, the Purkinje system may play a driver role in ventricular fibrillation.•A slow ventricular tachycardia may be caused by 2:1 activation ratio between the peripheral Purkinje system and the ventricular myocardium.•The Purkinje system appears as a potential target for catheter ablation of ventricular fibrillation in hypertrophic cardiomyopathy. •In hypertrophic cardiomyopathy, the Purkinje system may play a driver role in ventricular fibrillation.•A slow ventricular tachycardia may be caused by 2:1 activation ratio between the peripheral Purkinje system and the ventricular myocardium.•The Purkinje system appears as a potential target for catheter ablation of ventricular fibrillation in hypertrophic cardiomyopathy.