The purpose of the study is to evaluate the safety and effectiveness of the CentriMag ventricular assist system to help pediatric patients who have experienced heart failure during surgery and cannot be removed from cardiac bypass.

Inclusion Criteria:

1. Age 5 years to 16 years, inclusive
2. Inability to wean from cardiopulmonary bypass (CPB)

Exclusion Criteria:

1. Body weight < 20 kg
2. Severe aortic insufficiency
3. Unrestricted intra-cardiac communications (i.e. large VSD)
4. Pulmonary vascular resistance index (PVRI) > 10 IU
5. Presence of DIC
6. On hemodialysis (excluding hemofiltration)
7. Contraindications to systemic anticoagulation
8. Active systemic infection unresponsive to antibiotics
9. Unresolved malignancy
10. On other investigational VAS