CARDIAC PACING AND DEFIBRILLATION - Design and Development of Medical Electronic Instrumentation - page 372

TABLE 8.1 The Function of Autorhythmic (Pacemaker)
Cells Is to Initiate and Conduct Action Potentials That Are
Responsible for the Contraction of the Heart Muscle Cells a
Action Potentials

Tissue per Minute

SA node 60-80

AV node 40-60

Bundle of His 20-40

Purkinje fi bers 20-40

a Since the sinoatrial node is capable of depolarizing at the highest rate,
its activity usually controls the rate of the entire heart.

THE FIRST PACEMAKERS

In 1932, Alfred S. Hyman developed the first device used in the United States to stimulate

the heart electronically. He called his creation an arti

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fi cial pacemaker . His invention was

used to resuscitate people who had su ered from shock or hypothermia by utilizing brief

electrical currents. The Hyman device used mechanical induction of current to deliver
stimuli of approximately 3 mA directly to the heart via a needle electrode at rates of 30, 60
or 120 impulses per minute. His device had to be rewound every 6 minutes. In 1952, Paul
Zoll developed the

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first temporary external pacemaker. His device was large and limited
the patient's mobility to areas where it could be wheeled and plugged to an electrical out-
let. Electric shocks were coupled to the heart through electrodes placed on the skin, often
causing pain and skin burns. Later, Earl Bakken modi

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ed the circuit of a transistorized
metronome that he found in a back issue of Popular Electronics to operate as a portable
pacemaker.
It was not until 1958, after low-leakage transistors became available, that an implantable
pacemaker was constructed for human use. On October 8, 1958, Swedish physician Åke
Senning implanted the

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rst
recipient of the device developed by Rune Elmqvist of Elema-Schönander. The pacemaker
was a hockey-puck-sized device that comprised a handful of electronic components, includ-
ing two silicon transistors and a nickel-cadmium battery encapsulated in epoxy resin. The
pulse generator delivered pulses of approximately 2 V in amplitude and 2 ms in duration.
Batteries were charged noninvasively by RF induction of energy from a line-connected
vacuum-tube radio-frequency generator driving a coil at 150 kHz. The

fi first pacemaker in a human patient. Arne Larsson became the fi

first unit worked for
only a few hours before it failed. On the next morning, a second unit was implanted and
lasted for approximately six weeks.
The

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first successful long-term human implant of a pacemaker was achieved in Uruguay
on February 2, 1960 by Orestes Fiandra and Roberto Rubio. The pacemaker was manu-
factured by Elmqvist and was implanted in Uruguay in a 34-year-old patient with AV
block. Battery charging was done through the same RF link as that used in the

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first implant.
One charging session, which was done overnight, was enough to power the pacemaker for
about a month. This unit worked successfully for nine and a half months, until the patient
died of sepsis from an infection. Other successful implants of the Swedish pacemaker
followed in London. Soon after, William Chardack conducted the

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first human implant of
a pacemaker in the United States. The device powered by 10 mercury-zinc cells was
designed by Wilson Greatbatch.
In 1969, Fiandra began the Centro de Construcción de Cardioestimuladores del Uruguay
(CCC) with the purpose of producing pacemakers for use in Latin America at prices well
under those of U.S. devices. During the 1970s and 1980s CCC assembled pacemakers

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