Arrhythmias can be variable in their clinical symptoms and are mostly even asymptomatic. Suppression of arrhythmias is usually not very difficult, but the clinical value of the intervention is questionable. Only in the case of a history of myocardial infarction does treatment with beta-blockers appear to improve the prognosis, but the mechanism does not appear to be related to the suppression of arrhythmias. In view of the potentially dangerous effects of all anti-arrhythmics, extreme caution should be exercised in using them. Only in the case of a hemodynamic or symptomatic emergency should anti-arrhythmics be prescribed.