1. A method for determining an optimal output of an ablation catheter for a myocardial ablation in a patient, comprising: creating a three-dimensional image recording of an ablation region containing a myocardium for the myocardial ablation; segmenting the image of the ablation region; determining a location-dependent thickness of the myocardium in the ablation region based on the segmentation; and determining the optimal output of the ablation catheter as a function of the thickness of the myocardium for performing the myocardial ablation.