Is there a connection between atrial septal defect and patent ductus arteriosus?

To a degree: Both are congenital development defects. Atrial septum should seal and patent ductus should close after birth. When identified in infancy they are quite treatable. Also later but preferably as early as possible fir most.

Not really: They can occur together, but more ofter occur individually. Both cause l to r shunts (red blood returning to the lungs) and can result in CHF and/or damage to the lungs.