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About this Article
Written by: Vivian Chan
Written on: May 6th, 2013
Tags: biomedical engineering, electrical engineering, health & medicine, history & society
Thumbnail by: J. Heuser/Patrick J. Lynch; C. Carl Jaffe, MD
About the Author
Vivian Chan was an undergraduate Junior from Taipei studying Biomedical Engineering at the University of Southern California.
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Volume XV Issue I > Engineering Heartbeats: The Evolution of Artificial Pacemakers
Arrhythmia—a cardiac disease in which the heart beats irregularly or at an abnormal pace—is caused by faulty electrical signal generation within the heart at the SA node. Recognizing the electrical properties of the heart, engineers created a treatment device, the artificial pacemaker, by applying principles of electrical engineering. The device controls the rate and rhythm of the heartbeat by overriding faulty natural signals with generated electrical pulses. The first pacemaker was created in the 1920s, and subsequent innovations in batteries, transistors, and microprocessors allowed the pacemaker to be portable, wearable, and eventually implantable. Today, pacemakers can be programmed for different rates and automatic regulatory functions, but they are still limited in battery life and have risks of infection or failure. Engineers are applying the concepts of piezoelectricity and ultrasound to address these problems, and the results are promising for a new generation of smaller, safer pacemakers.

Introduction

We like to think we have complete control over our bodies – looking, touching, and moving wherever we want. However, there is one thing we cannot systematically control with our minds: our heartbeat. Even when the brain is resting at night, the heart never fails to keep beating at the same rate. This is because the heart serves the critical function of facilitating blood circulation, which in turn supplies oxygen to different organs in the body. A timely and constant delivery of oxygen is critical for proper body function: our cells rely on oxygen to perform basic tasks like cellular respiration, the process that harvests energy to fuel cellular activities. The interruption of the body’s oxygen supply for even a few minutes can have catastrophic effects, like the death of brain cells [1]. One of the most common medical conditions that can lead to interrupted blood supply is arrhythmia, when the heart beats at an abnormal rate due to heart signaling malfunctions. To treat this problem, engineers applied principles of electrical engineering and created the artificial pacemaker, a device placed in the chest or abdomen that generates electrical pulses to control the rate and rhythm of the heartbeat. Since the first artificial pacemaker of the 1920s, pacemakers have undergone significant improvements over the years through the combined efforts of electrical engineers and medical doctors. Moreover, different engineering disciplines have now been applied to the development of the pacemaker, and these new techniques offer exciting potential for pacemakers of the future.