[Invasive diagnosis of arrhythmias]

This paper deals with the methods, the indications and the clinical relevance of the invasive diagnosis of arrhythmias. The change of the indication of this method from bradyarrhythmias to tachyarrhythmias is particularly discussed. This method has developed from a purely diagnostic tool to a therapeutic instrument. During one investigation the diagnosis, the mechanism and the localisation of an arrhythmia can be detected and in addition the optimal therapy can be found. The complication rate is low provided that it is performed in specialized cardiological centers. This method has itself established as an important tool in diagnosis and treatment of tachyarrhythmias.