The purpose of DEFENSE-ELDERLY is to identify the prevalence of AF and evaluate the clinical impact of AF in elderly ESUS patients and no other known sources of stroke besides a high-risk patent foramen ovale, and compare it with elderly ESUS patients without high-risk PFO (no PFO or non-high risk PFOs)

The purpose of DEFENSE-ELDERLY is to identify the prevalence of AF and evaluate the clinical impact of AF in elderly ESUS patients and no other known sources of stroke besides a high-risk patent foramen ovale, and compare it with elderly ESUS patients without high-risk PFO (no PFO or non-high risk PFOs)

Inclusion Criteria:

• Patients ≥60 y/o with ESUS and PFO that is likely to have causative role (high-risk anatomical feature) (cohort A)
• Patients ≥60 y/o with ESUS without PFO, or with non-high risk PFO (cohort B)
• The patient or guardian agrees to the study protocol and the schedule of clinical follow-up, and provides informed, written consent, as approved by the institutional review board
• Patients who are scheduled to have implantable cardiac monitoring

Exclusion Criteria:

• Transient ischemic attack
• Lacunar infarction (infarction at subcortical area with a lesion diameter less than 2cm on MR)
• Presence of complex aortic atheroma (≥4mm in plaque thickness or presence of mobile components)
• Presence of ≥50% luminal stenosis (extra- or intracranial) in arteries supplying the ischemic area
• Unwillingness or inability to comply with the procedures described in this protocol
• Life expectancy < 1 years for any non-cardiac or cardiac causes

Patients ≥60 y/o with ESUS and PFO that is likely to have causative role (high-risk anatomical feature) (cohort A) and Patients ≥60 y/o with ESUS without PFO, or with non-high risk PFO (cohort B)