This study will evaluate the use of x-ray fused with MR images as an imaging tool to help guide catheter tools during diagnostic and therapeutic cardiac catheterization procedures.

Cardiovascular interventional procedures are currently conducted under the guidance of X-ray fluoroscopy. Magnetic resonance imaging (MRI) can provide increased soft tissue information about the cardiovascular system. By combining the familiar X-ray environment with superior magnetic resonance imaging, the investigator hopes to enhance and expand the capabilities of cardiac catheterization techniques.

The investigator will conduct cardiac catheterization procedures using XFM guidance in pediatric research patients who are undergoing medically necessary procedures. The investigator aims to decrease the exposure of these patients to the routine hazards of ionizing radiation and contrast exposure compared to the standard of care approach.

Inclusion Criteria:

1. Children and adults of any age
2. Undergoing clinically-indicated cardiovascular catheterization

Exclusion Criteria:

1. Cardiovascular instability precluding baseline medially-necesary MRI
2. Women who are pregnant
3. Women who are nursing and who do not plan to discard breast milk for 24 hours
4. All patients who are medically judged to have contraindication(s) to MRI scanning. Contraindications include implanted metal devices which are contraindicated for MRI scanning