The method involves calibrating a C-arm X-ray device (1) and electromagnetic position recording and mapping system (2) relative to each other, while a coordinate transformation is determined between a coordinate system (CR) assigned to the device and/or another coordinate system (CB) assigned to an image generated by the device and a third coordinate system (CM) assigned to the system. Position of a patient (P) is determined during recording of an image and/or during recording of electro-anatomical mapping, and is indirectly assigned to the image and/or the electro-anatomical mapping data. An independent claim is also included for a device for visual support of an application of catheters at heart of a patient.
