Everything about Wilson Greatbatch totally explained
Wilson Greatbatch (born
September 6 1919) is an inventor who advanced the development of early implantable cardiac
pacemakers. He is a graduate of
Cornell University and the
University at Buffalo. Greatbatch is often miscredited as the inventor of the pacemaker as a whole. He was responsible for a donation to
Houghton College in New York to create a graduate program in music.
The Chardack-Greatbatch pacemaker
The earliest known creation of an implantable pacemaker was by Åke Senning and
Rune Elmquist of
Sweden in
1958. Greatbatch improved upon the two men's earlier work by creating the
Chardack-Greatbatch pacemaker in
1960. It used Mallory mercuric oxide-zinc cells (
mercury battery) for its energy source, driving a two transistor, transformer coupled
blocking oscillator circuit, all encapsulated in
epoxy resin, then coupled to electrodes placed into the
myocardium of the patient's heart. The main difference between this pacemaker and the Swedish one is the battery technology used.
This
patented innovation led to the
Medtronic company of
Minneapolis commencing manufacture and further development of cardiac pacemakers.
The Greatbatch lithium-iodide battery cell
In
1968,
Catalyst Research Corporation of
Baltimore, Maryland developed and patented a lithium-iodide battery cell (USA patent 4049890). The cell used two elements at near ends of the
electrochemical scale, causing a high
voltage of 2.8V and an energy density near the physical maximum. Unfortunately, it had an internal
impedance which limited its current load to under 0.1 mA and was thus considered useless.
Greatbatch sought to introduce this invention into the pacemaker industry, which could readily utilize a high impedance battery. The early work was conducted in a rented area of the former
Wurlitzer Organ Factory in
North Tonawanda, New York.
Ralph Mead is understood to have headed the early electrochemical development.
Greatbatch introduced the developed
WG1 cell to
pacemaker developers in 1971, and was met with limited enthusiasm. The lithium-iodide cell manufactured by WG is now the standard cell for pacemakers, having the
energy density, low self-discharge, small size and reliability needed.
In the cell as developed for cardiac pacemaker application, the
anode is
lithium and the
cathode a proprietary composition of
iodine and poly-2-vinyl pyridine, neither of which is electrically conductive, however after processing by mixing and heating to ~ 150 °C for 72 hours the components react with each other to form an electrically conductive viscous liquid which, while still molten, is poured into the cell where it cools to form a solid. When the liquid contacts the lithium anode it creates a monomolecular layer of semiconducting crystalline lithium iodide. As the cell is discharged by the current load of the pacemaker, the reaction between the lithium anode and iodine cathode forms a growing barrier of lithium iodide, which being resistive causes the terminal voltage of the cell to decrease approximately as an inverse function of the volume of the barrier. Pacemaker designers use this characteristic to permit detection of incipient 'end of life' of the pacemaker's lithium cell.
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