The exercise-arm starts off with an introduction into physical training at the Department of Sports Medicine at the University in Tübingen. Ergospirometry and 6-min walk test will be performed to determine the patients' performance. Then the patients will be encouraged to exercise at home. The scales and intensities of physical training will vary interpersonally depending on patients individual performance. Pedometers and the ICD-integrated "Cardiac Compass" function will be used to verify work load, intensity and duration of the physical strain. The patients will be consulted by telephone regularly to affirm the study compliance. The physical activity in the control-arm will be monitored using the ICD-integrated "Cardiac Compass" function.