The 1999 Replica
Construction of the replica was completed for debut at the NASPE Annual Scientific Sessions in May 1999. (Figure 10) The Hymans’ patent narrative and diagrams served as the basis for the technical specifications and the 1932 published photographs for the physical layout of the replica. The goal was to build a replica that bore a physical resemblance to the original Hyman pacemaker. Duplicating the functionality of the original machine was a secondary goal.
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Figure 10: The replica constructed in 1999 by Szarka for the NASPE Annual Scientific Session had many of the features of the original. The lettering of the original (Figure 2) and the replica represent similar components: A) the magneto-generator; B’ &B") companion magnetic pieces; C) neon lamps; F) crank handle; G) impulse control; H) speed control; I) flexible electric cord; J) insulated electrode handle.
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The illustrations contained in the Hyman publication and the patent lack dimensions, and are without a ruler, but the photographs provide clues to the actual size of the device. The handle on the crank and the needle electrode provide information to deduce the general size and scale of the entire photo. It was assumed that the crank handles were 4 inches long (to fit comfortably in the hand), the base of the replica occupied roughly 1 square foot. Large hand-cranked spring motors are now all but impossible to find. A look-alike alternative was an antique hand-cranked wheel stone grinder, modified by removing the grinding stone and shaft, but still capable of a realistic feeling of resistance when cranked.
A large, antique electric motor was gutted for its housing and used to replicate the spring motor and gear housing. A small battery operated motor with a configurable gear reduction unit was mounted inside the shell. This motor protrudes from the front of the replica and drives the magneto-generator via a belt and pair of pulleys. The large pulley on the magneto-generator is a wheel from a toy doll wheelchair to avoid the pinch hazard presented by spoked pulleys. The "U" shaped magnets in the replica are ordinary bar stock, heated and hammered into shape.
The interrupter disc was prepared from copper-clad circuit board material, cut into a 3 inch disc, and processed to create the 4 segmental tracks. The finished disc was coupled to a second small motor and gear reduction unit to provide approximately half a revolution per second. A brush assembly glides over the surface of the interrupter disc and provides switch closure with each contact with the copper traces. and transport mechanism were fabricated from custom parts and miniature hardware. The brush position can adjusted so that contact occurs at a specific location to set the rate.
Many parts of the replica, such as the interrupter disc, duplicate the original device realistically. But the 1999 replica relies on battery power rather than a spring motor, and the source of stimulus current is the battery and not the magneto-generator. This raises the question whether the output of the replica matches the output of the original, but the pulse output of the original is unknown, despite differing reports by the inventor.
Intended Use of the Original
The patent application provides further evidence that Hyman intended the pacemaker to restore a normal heartbeat in people whose hearts had " ceased to function as a result of accident, electrocution, gas poisoning, ether anesthesia or shock of any kind" and in stillborn infants. He was addressing " stopped hearts . . . in healthy condition" rather than cases of heart block or other chronic conduction disorders.
Although Hyman always placed special emphasis on the utility of the pacemaker in reviving the healthy heart that had stopped because of some enormous insult, he occasionally advanced other suggestions and suggested that the pacemaker might find employment in cases of "rapid auricular fibrillation which are associated with low threshold values of the junctional and bundle tissues." Hyman himself suggested using the pacemaker to treat paroxysmal tachycardia of the atria or the ventricles. He speculated that "the artificial pacemaker in such a case would release a stronger stimulus for contraction than the ectopic focus, and it would thus control the rhythm of the heart. When control had been secured, the normal rate could reassert itself."
In 1935 Hyman told a medical audience that the pacemaker could "restore life" even in "cases of sudden death from heart diseases like angina pectoris and coronary thrombosis. . . . We have found that if the victim could be reached . . . within eight to twelve minutes from the time his heart had stopped," Hyman said, "it may be possible to start his heart going again. The clot can then be made to be absorbed in the system," he added, "and the patient may live for some time thereafter."
Hyman’s speculations approached the outer limits of medical understanding for the 1930s. Investigators of that era, Hyman included, had not grasped the practical importance of the distinction between standstill and fibrillation of the ventricles. Their attempts at pharmacologic, mechanical, and electrical stimulation of the asystolic heart had unpredictable results in part because many experimental subjects must have been in ventricular fibrillation. By the mid-1930s, Hyman had not made the connection between Stokes-Adams disease and the machine he had invented. He later submitted a claim that in 1942, other physicians had proposed to him that Stokes-Adams patients be paced through their episodes of syncope, and that he had successfully used the pacemaker in this way just 6 days later.
Subsequent Models: The "Hymanotor" and the "Flashlight" Pacemaker
Albert Hyman understood that development of the pacemaker into a practical technology would require competence that neither he nor his brother possessed. He decided to approach a medical-equipment manufacturer. Late in 1931, while his experiments with guinea pigs and rabbits were underway, the inventor contacted Adlanco, a New York subsidiary of the German company Siemens-Halske, which he may have known as a maker of ECG string galvanometer machines. According to a spokesman for Siemens, "Dr. Hyman offered to our firm an invention according to which the stopped heart was said to be resuscitated within 15 minutes, at most, after stoppage of the heart, provided death had not occurred as a result of some disease, but had been caused by a current surge or shock."
The spread of electric power had elicited an intense search for means of reviving electrical workers and others who had suffered accidental electrocution. Adlanco agreed, in the summer of 1932, to build up to 6 of the machines. By the end of the year, Hyman had received the first "Hymanotor," as the manufacturer dubbed it. But a spokesman for Siemens later reported that "in spite of several changes, made by our New York agency on the sample apparatus in accordance with Dr. Hyman’s wishes, no useful results were achieved."
Siemens/Adlanco also built a second Hymanotor and in December 1933 delivered it to Dr. Siegfried Koeppen at the Medical Policlinic of the University of Leipzig. Koeppen was the director of a research program into the problem of sudden cardiac death and was conducting animal experiments to discover some means of reviving people from cardiac arrest brought on by accidental electrical shocks. Using animals, Koeppen had evaluated a number of drugs and devices.
Over a period of 10 months in 1934, Koeppen experimented with the Hymanotor. He asphyxiated 3 cats, 15 guinea pigs, 7 rabbits, and at least 1 dog with morphine and attempted resuscitation without a single success. A Siemens representative who observed one of these attempts suggested two possible reasons: either the needle electrode was not being introduced to the correct spot in the heart, or the elapsed time from the onset of cardiac arrest had been too great. Koeppen himself offered a different explanation, reporting that"the Hymanotor yielded an ECG with a false [scheinbare] R-wave and lacking P, Q,S and T. The electrical stimulation is . . . ineffective; even after opening the thorax, it is not possible to produce contractions of the heart with these electrical stimuli. . . . With the Hymanotor the currents are very weak (up to about 2 mA) and ineffective even in normal animals, as I ascertained. Treatment with the Hymanotor is without effect." (Translation from the German, courtesy of Berndt L|deritz, MD)
Finally, in November 1934, Koeppen wrote directly to Hyman "asking for further particulars of the test conditions". Since this inquiry was not answered, Dr. Koeppen stopped his tests. "In this regard it seems that we have been victims of completely careless American reporting," commented a Siemens representative at company headquarters in Erlangen (Germany) two years after the company’s experience of being taken in by a "plumper Schwindel"--a clumsy fraud.
Hyman never mentioned Koeppen’s studies and their discouraging results. But in 1936, he described a third model pacemaker before a small audience of physicians in New York City. "It has been discovered during the past year" he said in possible reference to Koeppen’s findings, "that the currents which had been used, while exactly similar to the currents generated by the natural pacemake[r], were not effective in certain types of the dying heart, and it was found experimentally that another form of electric current would stimulate the heart better and more completely"
Since the natural pacemaker generates a current of about one-thousandth of a volt, it had been assumed that the artificial apparatus should duplicate that amount of voltage. It was found however, that the reason certain dying hearts failed to respond to the artificial current was because the current was not strong enough in those particular cases, as some hearts require more than one thousandth of a volt.
This new knowledge led to the development of the flashlight pacemaker. Whereas the original apparatus released one thousandth of a volt in the stopped heart, at the end of the needle for a period of one-tenth of a second, the ‘life flashlight’ produces one-fifth of a volt, or 200 millivolts, for only one-sixtieth of a second, in cycles of six--that is, six impulses of one-fifth of a volt each are released into the dying heart at intervals of one-sixtieth of a second.
Hyman added that "the new apparatus . . . has so far been applied to seven cases with good results in two." 25
The "life flashlight" was a different device from the Hymanotor. According to a reporter for the New York Times, it was ten inches long and weighed less than a pound. Through its needle electrode, it could deliver "different types and quantities of electric current." The head of the foundation that had been funding Hyman’s research announced that he would distribute flashlight pacemakers to selected hospitals and physicians later that year, 1936. But as far as is known, this plan was not implemented. For his part, Hyman never published a description of the flashlight pacemaker or reported formally on the "good results." 2>
For a fuller exposition see:
Furman S, Jeffrey K, Szarka G, The Mysterious Fate of Hyman’s Pacemaker.
PACE 2001;24:1126-1137. (Copyright, Futura Publishing Co. 2001)
| By: | Seymour Furman, MD
Professor of Surgery & Medicine
Albert Einstein College of Medicine
Bronx, NY | Kirk Jeffrey, PhD
Professor of History
Carleton College
Northfield, MN | George Szarka, MS-MOT
Technical Administrator
Montefiore-Einstein Heart Center
Bronx, NY |
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