THE FIRST FULLY INTERNAL CARDIAC PACEMAKER was implanted in 1958 to correct a case of cardiac arrhythmia. It failed just eight hours later. The Swedish engineer who received it would go through 25 pacemakers in the next 43 years of his life. Pacemakers are still temporary passengers, as are their technological relatives, implantable cardioverter defibrillators (ICDs), which jump-start the heart with more powerful pulses during sudden cardiac arrest. Reiner Riedler photographed this pile of those devices as part of a portrait series on lifesaving machines. But new advances are ensuring their stay is less invasive and longer-lived. In August 2015, researchers published encouraging preliminary results for a small “leadless” (wireless) pacemaker that is implanted using a catheter threaded through the leg, and placed within the heart itself. With a battery life of about nine years, it has been approved in Europe and is awaiting approval by the FDA.