[Uncommon cause of mitral insufficiency: pacemaker lead malpositioning in the left ventricle. Case report].

Cardiac pacemakers' insertions may be associated with different types of complications such as lead's malposition. The authors report the observation of lead's malposition in the left ventricular chamber through the interatrial septum. This malposition is potentially dangerous because of the potent risk factor for stroke and thromboembolism that the patient might run. The diagnosis of this malposition can be done by surface electrocardiogram and thorax X-ray. However, we do insist on the importance of echocardiography and furthermore of transesophageal echocardiography which can lead to a much better choice in the treatment.