Pacemaker

A pacemaker is an implanted medical device that generates electrical pulses delivered through electrodes to one or more chambers of the heart, regulating heart rhythm when the heart's natural pacing fails or becomes irregular. The physiologist John Alexander MacWilliam first demonstrated in 1889 that electrical impulses could stimulate heart contractions, and the engineer Earl Bakken built the first wearable external pacemaker in 1958; the first fully implantable pacemaker, designed by the inventor Rune Elmqvist and the surgeon Ake Senning, was implanted on October 8, 1958, at the Karolinska Institute in Sweden, in the patient Arne Larsson, the world's first pacemaker recipient. Larsson's first device failed after three hours and a second lasted only two days, but he went on to receive twenty-six pacemakers over his lifetime, and the development of lithium-iodide batteries in 1971 later extended device life from roughly a year to over a decade, turning the pacemaker into a reliable long-term therapy.