During an electrophysiological examination (EPS), catheters are placed at various points in the heart. This allows the electrical properties of the heart to be determined. Cardiac arrhythmias can be triggered, terminated and localized. The aim of an EPS is to identify and localize the patient’s arrhythmia so that it can be treated in the next step. In addition to medication, treatment options include ablation, i.e. sclerotherapy of the respective arrhythmia using heat (radio frequency) or cold energy (cryoablation).