Ventricular Fibrillation in PRKAG2 Cardiomyopathy: A Genetic Arrhythmia Substrate Beyond Wolff-Parkinson-White

PRKAG2 syndrome is a rare autosomal dominant glycogen storage cardiomyopathy characterized by left ventricular hypertrophy, ventricular pre-excitation, and progressive conduction system disease.

We report the case of a 25-year-old woman with genetically confirmed PRKAG2 syndrome who presented with an out-of-hospital cardiac arrest. Echocardiography revealed preserved left ventricular systolic function with mild concentric hypertrophy and marked apical thickening. Cardiac magnetic resonance imaging showed anterolateral trabecular hypertrophy without evidence of myocardial fibrosis. Electrophysiological study excluded Wolff-Parkinson-White syndrome and instead identified a fasciculoventricular accessory pathway. Given the occurrence of ventricular fibrillation and the associated arrhythmic risk, a transvenous implantable cardioverter-defibrillator was implanted for secondary prevention.

This case illustrates the atypical presentation of arrhythmias that deviate from classical patterns, such as those seen in Wolff-Parkinson-White syndrome.

Individualized risk assessment, close electrophysiological monitoring, and consideration of early implantable cardioverter-defibrillator implantation are important in PRKAG2-related cardiomyopathy.