How do you manage patients with atrial fibrillation having a thromboembolic infarct despite being on adequate anticoagulation?  

This scenario is always challenging. In terms of anticoagulation, the efficacy of DOACs in preventing embolic events in AF patients is around 70%, which is impressive compared to warfarin but not foolproof. In cases of a second embolic event while on anticoagulation, two reasonable approaches are of...

In addition to what Dr. @Farooqui and Dr. @Kirshner said, I would like to add that evaluating for underlying hyper-coagulable states like occult or active malignancy or anti-phospholipid antibody syndrome. There have been reports of higher DOAC failure rates in those with aggressive forms of cancers...

I would strongly consider L atrial appendage closure. If not an option, switch anticoagulant, perhaps to warfarin.