A rare case of sinus venosus atrial septal defect: Malpositioned right atrial pacemaker lead in the left atrium.

Incidental discovery of sinus venosus atrial septal defect (SV-ASD) in the elderly is rare. This defect allows for lead malpositioning during pacemaker placement and can lead to catastrophic cardioembolic events. Post-pacemaker implantation, chest radiography should be obtained to detect malpositioning early, and if detected, lead adjustment is recommended; if identified later, treatment with an anticoagulant is feasible. SV-ASD repair may be considered as well.