The heart and the brain are closely related, not only proverbially but also anatomically and pathogenetically. Cerebral circulation begins in the heart, through which a major pathomechanism of stroke is predestined: 20-30% of all cerebral infarctions are cardioembolically related. Both organs are equally affected by atherosclerotic processes. Despite this close relationship, generalizing extrapolations from heart to cerebral infarction are usually not applicable. The occurrence of coronary infarction is almost exclusively due to atherosclerosis with plaque rupture, whereas embolic mechanisms such as in cerebral infarction or microangiopathic processes play almost no role. On the other hand, the brain also influences the cardiovascular system. Thus, infarctions particularly in the region of the right insular cortex can induce cardiac arrhythmia and ECG and blood pressure changes. Additionally, vegetative crises with increased sympathicotonia and increased parasympathicotonia are common clinical observations in severe brain disease. A close relation between the two organs can also be observed in preventive pharmacotherapy. Similar principles, however, stand in contrast to considerations of various clinical risks and values, as can be seen for example in anticoagulation or thrombolysis. In this study, special attention is paid to cardioembolic stroke and preventive medicine aspects of coronary and cerebral vascular disorders. In particular, stress is placed on the discerning of commonalities and various evaluations of test results.