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Artificial pacemakers, with their generators and wire leads, can be either external or internal devices. Generally, they are small battery-run devices which help a heart beat in regular rhythm. The artificial pacemaker produces an electrical impulse which stimulates the heart to beat.
The heart has a natural pacemaker called the sinoatrial node (SA node). The SA node includes specialized cells at the top level of the upper chamber in the heart which help the heart maintain its beat under normal circumstances. Chambers of the heart contract when an electrical impulse moves across each one.
In order for a heart to maintain its beat correctly, that signal has to travel via specific pathways to get to the lower heart chambers, the ventricles. If the natural SA pacemaker fails, it can result in one's heart beating too slow, too fast, or too irregularly. This is one reason an artificial pacemaker would be needed. Rhythm problems might also occur due to blockage of the electrical pathway in the heart. This is another reason an artificial pacemaker might be needed.
The artificial pacemaker generator is typically implanted under the skin through a small incision. An electrode is implanted adjacent to a wall in the heart, and electrical charges move via that wire toward the heart. The generator is connected to the heart by other small wires. Impulses flow through the leads to the heart and are timed to flow at regular intervals, just like the impulses from the heart's natural pacemaker. Artificial pacemakers have sensor modes which prevent pacemakers from sending an impulse if one's heartbeat gets above certain levels.
Wilson Greatbatch invented pacemakers in 1958. He installed one resistor that had the incorrect resistance while he built an oscillator for recording heart sounds. It started to give an electrical pulse. At that point, he realized that this device might potentially be utilized to regulate heart function. Later, he invented a lithium battery which could power pacemakers.
Arne Larsson, a Swedish engineer, was the first individual to get a pacemaker internally. Viral infection had damaged the electrical circuits in his heart. That caused bradycardia, lessened blood flow toward the brain, and recurring problems which resulted in fainting. On 8 October 1958, heart surgeon Dr. Ake Senning and electronics engineer Dr. Rune Elmquist put together a small pacemaker and implanted it into Larsson's chest. The pacemaker was so successful that Larsson lived to be age 86; he died of melanoma, not heart disease.