AMPLATZER Duct Occluder II Clinical Study

Inclusion Criteria: * Subject must have diagnosis of a PDA * Subject must have a PDA \< 5.5mm in diameter by angiography * Subject must have a PDA \< 12mm in length by angiography * Subject must have a PDA \> 3mm in length by angiography * Subject/legally authorized representative must give consent to participate in the clinical study * Subject/legally authorized representative must consent to follow-up for the duration of the clinical study Exclusion Criteria: * Subject must not be \< 6 kilograms for the procedure * Subject must not be \< 6 months of age * Subject must not be ≥ 18 years of age * Subject must not have a descending aorta \< 10mm in diameter * Subject must not have a right to left shunt through the patent ductus arteriosus * Subject must not have PVR above 8 Woods units or a Rp/Rs \>0.4 * Subject must not have intracardiac thrombus * Subject must not have additional cardiac anomalies requiring surgical or interventional correction * Subject must not have history of more than two lower respiratory infections within the last year (i.e., pneumonia) * Subject must not have active infection requiring treatment at the time of implant * Subject must not have contraindication to anticoagulation treatment * Female subjects of child bearing age must not be pregnant or desire to become pregnant within six months post implant\* * Subject must not be participating in another study for an investigational drug and/or device that may clinically interfere with this study's endpoints * If the subject desires to become pregnant after six months post-implant, further restriction is at the discretion of their physician.