Introduction. The inadvertent lead malposition in the left heart chambers (ILMLH) is an under-recognized event which may complicate implantation of cardiac electronic devices (CIEDs). Methods and Results. We investigated the clinical conditions associated with ILMLH and the treatment strategies in these patients. We made a systematic review of literature and identified 132 studies which reported 157 patients with ILMLH. Mean age of patients was 68 years and 83 were women. ILMLH was diagnosed, on average, 365 days after CIEDs implantation. Coexisting conditions were patent foramen ovale in 29% of patients, arterial puncture in 24%, perforation of the interatrial septum in 20%, atrial septal defect in 16% and perforation of the interventricular septum in 4%. At the time of diagnosis of ILMLH, 46% of patients were asymptomatic, 31% had acute TIA or stroke and 15% had overt heart failure. Overall, 14% of patients were receiving anticoagulants at the time of diagnosis of ILMLH. After diagnosis of ILMLH, percutaneous or surgical lead extraction was carried out in 93 patients (59%), whereas 43 (27%) received anticoagulation. During a mean 9-month follow-up after diagnosis of ILMLH, 4 patients experienced TIA or stroke (3 on oral anticoagulant therapy and 1 after percutaneous lead extraction). Conclusion. ILMLH is a rare complication which is usually diagnosed about one year after CIEDs implantation. An early diagnosis of ILMLH is important. Lead extraction is a safe and effective alternative to anticoagulants.