Coronary angiography and measurement of fractional flow reserve (FFR) are used for anatomical and functional assessment of coronary stenoses. The achievement of maximal coronary hyperaemia is crucial for an accurate calculation of FFR. Although adenosine and papaverine have been well validated, their mechanisms of action as well as methods of administration have some limitations. New and better agents to induce hyperaemia are therefore still being sought. Currently regadenoson, a selective adenosine A2A receptor agonist, seems to possess the characteristics of the almost ‹ideal› hyperaemic stimulus.