Implantable Cardioverter Defibrillators (ICDs) have revolutionized the prevention of sudden cardiac death, particularly in patients with structural heart disease or ventricular arrhythmias. However, despite being generally safe, complications can arise during implantation. One rare but clinically significant event is inadvertent placement of a transvenous ICD lead into the left ventricle via a Patent Foramen Ovale. Such malpositioning carries a high risk of thromboembolic events and may go unrecognized until stroke or systemic embolism occurs. We describe a case of a patient who was found to have an ICD lead malpositioned in the left ventricle, 17 months after implantation. She underwent a successful lead extraction and a new lead placement in right ventricle.