A method for providing measuring data for the precise local positioning of an ablation catheter comprises the recording of electrophysiological potential curves in a plurality of positions of the ablation catheter with regard to a potential measurement on a reference catheter. An x-ray image is recorded in each of the positions and the position of the ablation catheter in each instance on the x-ray image is characterized by a marker. The electrophysiological potential curves are coupled in a data-related manner with the markers. When a marker on the screen displaying the x-ray image is clicked on, the associated electrophysiological potential curves appear highlighted on another screen, if necessary in color or with increased brightness. Conversely, the x-ray image with the marker is queried, i.e. displayed and the marker highlighted when the potential curve is activated on a screen displaying the potential curve.