A frequently underdiagnosed complication of pacemaker and implantable cardioverter defibrillator lead implantation is the unintentional advancement of the leads into the systemic circulation. We report a case encountered in our clinic in a 70-year old man evaluated in a neighbouring clinic with symptoms of transient ischaemic attack with initially unclear aetiology. Posterior-anterior chest X-rays suggested that the lead was in the left heart. This finding was confirmed by transthoracic and transoesophageal echocardiography.