The conglomerate of microorganisms, inflammatory cells, fibrin and platelets that constitutes the characteristic lesion of infectious endocarditis, that is, vegetation, was considered as a major criterion of infectious endocarditis in the 90s thanks to the development of ultrasound. Ecocardiography allows the diagnosis of complications derived from the infection, such as valvular perforation, prosthetic dehiscence, fistula or abscesses. One of the most infrequent complications is the mitral pseudoaneurysm. It has its origin in the impact of a jet of aortic regurgitation on the anterior leaflet of the mitral valve, which is why we have called it mitral fracking. A 60-year-old man who had a recent history of pneumonia and for whom he was still receiving antibiotic treatment, debuted suddenly with dyspnea of minimal effort. He went to a cardiology clinic where he was found to have severe mitral regurgitation. He was directly derived to cardiac surgery of our hospital. Prior to the intervention, a transesophageal ultrasound study was performed in our department, which showed the following findings: a bicuspid aortic valve with a small vegetation on its aortic surface (Figure A, surgical piece), a protuberance on the anterior mitral leaflet (Figure B) with internal flow that caused systolic expansion towards the atrium (Figure C) and diastolic collapse towards the ventricle (figure D): the mitral pseudoaneurysm. The therapeutic action was based on the replacement of both valves with mechanical prostheses. The blood cultures were negative, but the surgical piece revealed unequivocal histological findings of infectious endocarditis. Currently, the patient is stable and the valves are normofunctional in the regular follow-up controls. Abstract 91 Figure.