For the treatment of an insufficient cardiac valve or a cardiac valve with a stenosis, a device is provided that comprises a micro axial pump (40). The pump portion (14) of the micro axial pump carries a dilating device (18) suitable for pushing open a stenosis in a valve. The dilating device is designed as a high-pressure balloon. During dilation, the micro axial pump (40) operates so that the heart is relieved. With insufficient cardiac valves, a stent (21) is fastened to the dilating device (17), the stent surrounding a flexible cardiac valve prosthesis (20). By dilation, the stent (21) is pressed against the insufficient cardiac valve and the same is passivated. The cardiac valve of the cardiac valve prosthesis is unfolded to assume the function of the natural cardiac valve.