We report the implantation of a Berlin Heart ventricular assist device (VAD) in a 4-year-old boy with hypoplastic left heart syndrome previously palliated with Norwood and Glenn operations, who presented with progressive ventricular failure and hypoxemia. Insertion of a 30-mL pneumatic pediatric pump with cannulation of the systemic right ventricle and aorta had a salutary effect on cardiac output, improving oxygen saturations. While awaiting heart transplantation, multiple thromboembolic complications developed and he died, despite therapeutic heparinization and aspirin therapy. Important lessons learned about VAD support in Glenn physiology, anticoagulation, and complications of the Berlin Heart are discussed.