Pompe or Glycogen Storage Disease type II (GSD-II) is a genetic disorder affecting both cardiac and skeletal muscle. Historically, patients with the infantile form usually die within the first year of life due to cardiac and respiratory failure. Recently a promising enzyme replacement therapy has resulted in improved clinical outcomes and a resurgence of elective anaesthesia for these patients. Understanding the unique cardiac physiology in patients with GSD-II is essential to providing safe general anaesthesia.