Atrial and ventricular tachycardia are typically treated with Implantable Cardioverter Defibrillators (ICDs). Current dual-chamber ICDs have over 200 parameters, which have to be set all properly to ensure an accurate ICD programming. Since this is a time-consuming procedure, an expert-system to calculate a complete set of ICD parameters based on the given clinical patient-data was developed, where the expert knowledge was acquired and implemented into a knowledge base in cooperation with cardiologist physicians.