Cardiac arrhythmia are frequently observed after stroke. They may on one hand be causative for the stroke mainly in case of atrial fibrillation but on the other hand present severe complications of the stroke. In addition, cardiac comorbidity as well as acute myocardial infarction are frequently found in acute stroke patients. Diagnostics to identify cardiac arrhythmia in the acute phase of stroke care thus have an important role not only for adjusting the correct secondary prevention but also to prevent cardiac complications potentially reducing morbidity and mortality.