The authors present in their review recent findings on the importance of the autonomous nervous system in disorders of the cardiac rhythm. They emphasize its modulating action in the development, maintenance and termination of many arrhythmias. Vegetative nervous influences may play a part in people without organic heart disease but are manifested more markedly above all at sites of previous damage. Mechanisms by which the autonomous nervous system influences the development and course of arrhythmias are very complicated and so far not completely elucidated. In addition to a generalized tonus of the sympathetic nerve and the parasympathetic nerve and their predominance a very important part is also played by regional and local changes of cardiac autonomous influences. Elucidation of mechanisms and indicators of vegetative factors influencing the heart creates prerequisites for their modulation by medication as well as other procedures.