The authors report the case of a 78 year old woman admitted to hospital for recurrent cerebrovascular accidents, the initial investigation of which was normal. This pacemaker patient had a displacement of the definitive ventricular pacing catheter which was positioned in the left ventricle through a patent foramen ovale. The diagnosis was suspected on clinical and echocardiographic examination and confirmed by transthoracic and transoesophageal echocardiography. In view of the risk of systemic embolism, the pacing catheter was repositioned by an endovascular approach in the right ventricle.