Abstract
Background: Cardiac electronic device implantation may be associated with complications. Case Summary: This is a report of inadvertent implantation of implantable cardioverter-defibrillator lead through an unrecognized sinus venosus atrial septal defect into the left ventricle that was not diagnosed early after implantation. Six months later chest x-ray showed an abnormal lead course that was confirmed with echocardiography as to be in the left ventricle. Surgical removal of the implantable cardioverter-defibrillator lead, repair of atrial septal defect, and correction of abnormal pulmonary venous connections were performed. Meanwhile, follow-up of the patient receiving a new dual chamber permanent pacemaker from the contralateral side and discussion of the aforementioned complication are addressed. Conclusion: Early diagnosis of device implantation complication is of paramount importance and prevents potential catastrophic complications.