Pacemaker is a small electrical device placed under the skin to help the heart beating. It is used in people suffering from heart abnormalities like conduction defects, heart blocks, AV or SA Node dysfunction, After Acute Phase of Myocardial Infarction, Post-cardiac transplantation, etc. The Chest X-ray shows the pacemaker with its two leads i.e. atrial and ventricular leads. Picture credit: https://johnsonfrancis.org/professional/dual-chamber-pacemaker-chest-x-ray/amp/