Computer artwork showing a leadless pacemaker. These are single-chamber, programmable devices delivered minimally invasive by catheter via the femoral vein into the right ventricle of the heart. They contain a lithium battery, electrode and fixation device in a body one-tenth the size of a traditional pacemaker. A sensor and stimulatory electrode sense the heart's activity and determine when to deliver or withhold stimulation. The device's battery life depends on the amount of pacing required but is estimated to be seven to 10 years. The type shown anchors to the myocardium with curved pronges or tines. Leadless pacemakers have the potential to replace conventional pockets and leads and improve the the safety of pacemakers, avoiding infections, lead deslodgements and failures.