Embodiments include an active implantable medical therapy and/or monitoring system that includes at least one implant. The at least one implant includes at least one ultrasonic transducer directly or indirectly connected to a control and evaluation unit in order to emit and receive ultrasonic signals. The control and evaluation unit prompts an emission of ultrasonic signals by the at least one ultrasonic transducer cyclically or in a triggered manner and evaluates received ultrasonic signals such that the control and evaluation unit identifies an actual position or change in position of one or more of the at least one implant and an electrode line.
