1. A system ( 100 ) for visualizing a cardiac parameter at a plurality of positions in a myocardium and at a plurality of stress levels, the system comprising: a determination unit ( 110 ) for determining a value of the cardiac parameter at a position from the plurality of positions in the myocardium and at a stress level from the plurality of stress levels on the basis of stress level cardiac functional data; and a visualization unit ( 120 ) for visualizing the determined value of the cardiac parameter by displaying a point in a viewing plane, where in a polar coordinate system in the viewing plane: a radial coordinate of the point visualizes the determined value of the cardiac parameter; and an angular coordinate of the point visualizes an angular coordinate of the position in the myocardium in a cylindrical coordinate system.