Prosthetic valve endocarditis (PVE) is the most feared complication after valve implantation. It usually results in substantial morbidity and mortality in the postoperative period. An adverse effect on the annulus can cause conduction disturbances in the atrioventricular (AV) node, resulting in a high-degree AV block. This study describes a case of PVE that predominantly presented with sustained monomorphic ventricular tachycardia, which indicated a severe clinical course of PVE caused by a significant displacement of the aortic valve prosthesis. In our opinion, a very pronounced flap valve motion of the dehisced valve probably caused, in the critical moment, coronary artery blood flow limitation by means of coronary microembolization, which produced temporary ischemia and provoked sustained ventricular tachycardia. Furthermore, disturbances of rhythm such as ventricular tachycardia in the setting of endocarditis indicate a high-risk condition and should mandate fast and thorough noninvasive diagnostic procedures to obtain correct diagnosis even in the case of mild, slowly progressing disease.