Increasingly, insertable cardiac monitors (ICM) have been used to detect Atrial Fibrillation (AF) in patients with cryptogenic stroke or embolic strokes of undetermined source (ESUS). We aim to examine the characteristics of these patients who were subsequently found to have AF.We studied 83 consecutive patients who were comprehensively evaluated using neuroimaging and vessel imaging (computed tomography angiography, magnetic resonance angiography, or transcranial and extracranial Doppler sonography) to have met the previously established ESUS criteria. All 83 patients had ICM implanted between 2015 and 2017. All patients were followed up for at least 1 year, with a median follow-up period of 1.5 ± .5 years. We compared the baseline clinical, laboratory, echocardiographic, neuro-imaging profiles, and clinical outcomes in terms of functional recovery, recurrent stroke, and mortality in patients with and without detected AF.AF detection rate in this ESUS cohort was 12% over the study period. Patients with detected AF were associated with bilateral infarcts pattern at presentation (30% versus 5.5%, P = .035). Infarcts involving multiple vascular territories was not significantly associated with the detection of AF. There were no significant differences in the other clinical characteristics and outcomes between the AF group compared to the group without detected AF. Echocardiographic parameters including left ventricular ejection fraction and left atrial diameter were also not shown to be significantly different.Our study found that a neuroimaging profile of bilateral infarcts was associated with AF detection using insertable cardiac monitor in ESUS patients. Larger prospective studies are needed to validate our findings.