The goal of this clinical trial is to learn if a computer software program (cardiac simulator) for surgical planning will lead to improvements in patient care by decreasing the incidence of unsuccessful interventions and reinterventions for pediatric patients with congenital heart disease. It is not a commercially available device to treat congenital heart disease in pediatric patients. The main aims are:

To provide safe pre-operative testing of surgical approaches with a computer model cardiac simulator.

To aid surgeons in envisioning different surgical approaches for each individual patient.

To bolster the standard of care surgical planning discussions which will be particularly useful for patients with unique, complex congenital heart disease.

Participants will:

Consent to being randomized with a 50% chance of receiving standard of care "on the fly" surgical planning discussion as is current practice or assisted surgical planning discussion with the aid of the computer software cardiac simulator.

Receive results of their computer simulated findings during their surgical planning discussion if they are in the cardiac simulator group.

The computer software will be developed at the Cardiovascular Biomechanics Computation Lab at Stanford.

Inclusion Criteria:

• The inclusion criteria are pediatric patients ages 0-17 with a congenital heart disease (CHD) diagnosis of 1) congenitally corrected transposition of the great arteries (cc-TGA) with ventricular septal defect (VSD), 2) double outlet right ventricle (DORV) with remote VSD, or 3) other single ventricle conditions.

Exclusion Criteria:

• Adult patients with CHD.

After consent to participate in the study, patient will be entered into a random allocation sequence for standard of care (SOC) or cardiac simulator groups.

Patient and surgeon will both be notified which group they have been assigned to.