Stimulation device for electrotherapy and method for checking the polarity of contact electrodes

A stimulation device for electrotherapy, in particular defibrillator and/or an external pacemaker device, comprising:

• at least two contact electrodes, which can be applied to suitable stimulation positions on the body of a patient, and are configured to subject the body of the patient to current pulses, wherein the first of the at least two contact electrodes acts as a charging electrode having positive polarity and the second of the at least two contact electrodes acts as a discharging electrode having negative polarity with respect to an emitted current pulse;
• a current pulse generator, which is or can be connected to the contact electrodes via line connections;
• and
• a signal evaluation unit, which is or can be connected to the contact electrodes, wherein the stimulation device is arranged, through the contact electrodes applied to the body of the patient, to record endogenous signals from the patient specific to the respective stimulation positions of the contact electrodes and to transmit them to the evaluation unit, wherein the evaluation unit is configured to determine the actual stimulation positions of the contact electrodes on the body of the patient based on the specific signals detected by the contact electrodes.