A cardiac pacemaker is a surgically implanted electronic device that regulates a slow or erratic heartbeat. The first artificial pacemaker was invented by Dr. Mark Lidwell, an Australian anesthetist, who developed an external device running on an alternating current that required a needle to be inserted into the patient's upper heart chamber (ventricle). In 1928 Lidwell used the device to resuscitate a baby born in cardiac arrest at the Crown Street Women's Hospital in Sydney. Lidwell reported the case to the Third Congress of the Australian Medical Society in 1929, but kept a low profile due to controversy at the time surrounding research into artificially extending human life.
In 1932 U.S. physiologist Albert Hyman (1893-1972) independently developed an electromechanical instrument, powered by a spring-wound, hand- cranked motor, that he referred to as an "artificial pacemaker."The first internal pacemaker was developed by Swede Rune Elmqvist and implanted into a patient in 1958 at the Karolinska University Hospital, Sweden, by surgeon Ake Senningn. These early models were powered by mercury-zinc batteries, lasting only two or three years. In 1973 a lithium-iodide fuel cell was developed that could last for around six years.
Today more than 100,000 pacemakers are implanted each year in the United States. Modern pacemakers have sophisticated programming capabilities and are extremely compact. The device contains a pulse generator, circuitry programmed to monitor the heart rate and deliver stimulation, and a lithium iodide battery, with a life of seven to fifteen years.
