According to Kaplan Pathology, a paradoxal embolism happens when initially there is ASD and a DVT occurs that crosses the ASD. But I think since the whole point of a paradoxal embolism is that it's a venous clot that broke off and went into the heart, then it's probably associated with both ASD and VSD. I hope this helps, it's just my take on it.
Here, found this it might help understand it better:
"The intracardiac communication between the venous and arterial circulations can be in the form of a PFO, atrial septal defect (ASD), pulmonary arteriovenous malformation, ventricular septal defect, Ebstein anomaly, and patent ductus arteriosus."