A medical viewing system (10) determines a viewing plane and provides medical images with the determined viewing plane. The medical viewing system (10) includes an X-ray image acquisition device (1), an echocardiographic image acquisition device (2) and a processing unit (3). The X-ray image acquisition device (1) is adapted to acquire an X-ray image in an X-ray imaging plane. The echocardiographic image acquisition device (2) is adapted to acquire a plurality of echocardiographic images. The processing unit (3) is adapted for a determination of an indicator in the X-ray image indicating a viewing plane for an echocardiographic image. The indicator may be an indicator line (41) in the X-ray image indicating the viewing plane perpendicular to the X-ray imaging plane. The processing unit (3) is further adapted for registering or fusing the X-ray image and the plurality of echocardiographic images together, and for then providing an echocardiographic image in the identified viewing plane. The identified viewing plane may be related to specific plane of a device (valve clips, plugs. . .) or of a specific anatomical structure.