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Voices of Experience Frederik Nebeker and Michael Geselowitz IEEE History Center, Piscataway, New Jersey Those Who Have Played Pioneering Roles in Biomedical Engineering Come from Many Fields. In These Excerpts from the Oral-History Project, Some of the Pioneers Tell of Their Involvement in Shaping the Discipline. The oral-history project, initially funded as part of the EMBS anniversary project, was substantially expanded through a grant from the United Engineering Foun- dation, which made possible the inter- viewing of an additional dozen pioneers of biomedical engineering from other engineering fields, mainly chemical and mechanical engineering. This article in- cludes a large collection of excerpts from all of the oral histories, hence providing some indication of the full range of bio- medical engineering. ©PHOTODISC 0739-5175/02/$17.00©2002IEEE Nebeker: Your work was on control systems. at the highest level of experimental cardiology, Robert Arzbaecher and he found a trained electrical engineer to help Arzbaecher: Yes, I focused my graduate him with instrumentation problems. During that Director, Pritzker work on that. When I finished my degree in 1960 year we did the first isolated human heart map- Institute of Medical and left [the University of Illinois at] Urbana I ping experiment and published in Circulation. Engineering Illinois took a teaching position at the Christian Institute of Technology Brothers College in Memphis, Tennessee. * * * * * (interview by Christian Brothers College had a good under- Frederik Nebeker on graduate engineering school, particularly in the Nebeker: What was the impact of the mini- electrical area. … It was not a small school, but computer on electrocardiography and similar 14 October 1999) not much was going in on the area of control. areas? Certainly not much in my area of reactor control Arzbaecher: There were two impacts. First, was going on in Memphis. I taught electrical en- it made it possible for many laboratories without gineering but was not able to continue my re- major computer resources to acquire significant search. It was in that context that my conversion computing resources. Secondly, it led to digital from electrical to biomedical engineering be- signal processing, which is now standard, and gan. also to on-line real-time signal processing. For a year I looked for a challenging re- Without the smaller computer and its capabili- search opportunity in Memphis to go with my ties for on-line acquisition, analog-to-digital teaching. Then I met Daniel Brody at a cocktail conversion, and processing in the digital do- party. He was a cardiologist from the Univer- main, that wouldn’t have happened so quickly. sity of Tennessee College of Medicine in Mem- My experience before then had been with punch phis. Unknown to me at the time, he was a very card machines, batch processing, and number well-known cardiac theoretician. Brody’s un- crunching. dergraduate training was in physics. … When I found out more about his background, it was * * * * * the beginning of a wonderful relationship. I spent the next seven years working with Brody Nebeker: Was delivering the drug automati- in his laboratory every chance I could get, on cally your objective? Saturday, Tuesday, and Thursday afternoons to Arzbaecher: Yes. That was my dream. It has the extent I could arrange my teaching sched- been a long time in bearing fruit. ule. We worked in what is now called theoreti- cal electrocardiography, which is the physical Nebeker: It sounds very ambitious for the and mathematical basis for interpretation of the 1970s. human electrocardiogram in health and dis- Arzbaecher: Yes, it was. Support came ease. Brody and I wrote a lot of papers together. from the pharmaceutical company G.D. Searle. That’s how I became a biomedical engineer. They were particularly interested in finding out whether their drug Norpace was effective in * * * * * treating atrial arrhythmias. Necessity being the mother of invention, I invented the esophageal Arzbaecher: After six years of theoretical electrode for recording the electrocardiogram mathematical modeling work I had an urge to from the esophagus. get closer to clinical electrocardiography. I had an opportunity to go to Europe for a year on a * * * * * National Science Foundation fellowship, and Dan Brody set up an opportunity for me to work Arzbaecher: It is interesting how I discov- in the laboratory of Dirk Durrer at the University ered the pill electrode. … In the lab, I had a grad- of Amsterdam. That experience was of major uate student of mine push a catheter electrode significance in my career. Durrer had a concept down my nose and into my throat and esopha- for removing the human heart soon after clinical gus. I was able to measure a beautiful p-wave, death and keeping the heart alive long enough to which was an atrial recording in the electrocar- map its electrical activation. This had been done diogram. with the hearts of animals, and Durrer was poised to do the same thing with the human Nebeker: Did you get a much clearer signal heart. The instrumentation requirements of that that way? task were significant. With the isolated heart on Arzbaecher: The p-wave obtained is three a perfusion stand, needle electrodes were placed to four times bigger than QRS. Compared to all over the heart to record on a multichannel ba- routine electrocardiography on the body sur- sis. This was in the mid-60s, when that was not face, the esophagus gives a beautiful p-wave an easy thing to do. My time in Amsterdam was from the atrium. The recording we made was fortuitous for him and for me. I became involved clear, but it hurt. That night I could still feel the irritation in my throat that had been caused by Arzbaecher: One day in my laboratory in the catheter. Iowa City I disconnected the pill electrode from the electrocardiograph, connected it to an exter- Nebeker: You’re in the class of people who nal stimulator, and discovered I could pace my experiment on themselves. heart. Arzbaecher: That was in the days before we Nebeker: More experiments on yourself. were so careful about human investigation. My Arzbaecher: By connecting the electrode lo- throat and sinuses hurt, I realized that the problem cated immediately behind the left atrium to an was that big old stiff catheter. All I really wanted external pacemaker I was able to capture the were the two rings at the end of the catheter. The heart and run it at any rate I wanted. next morning I went into the lab, took a pair of di- We proved that esophageal pacing was both agonal cutters, and stripped away the polyethyl- safe and effective and received premarket ap- ene coating until I was left with the tip of the proval. No longer a substantial equivalence catheter and the pair of wires. Then I buried the thing, this required the full FDA premarket catheter tip in a spoonful of ice cream and swal- route. It was necessary to perform experiments lowed it. My students laugh about this. One does- and prove there would be no damage to the n’t chew ice cream, so the bipolar pair of esophagus. It also had to be proved that this de- electrodes caused no problem. I just swallowed it, vice was effective in pacing the heart. Following and down went the pill. That was the first pill all those studies we appeared before the FDA electrode. That was the business end of a catheter Cardiology Advisory Board at the end of 1986 electrode with a bipolar pair and a pair of wires and got the PMA approved. I developed a small holding it up. Within a week or two I discovered a battery-operated electronic external pacemaker source of very thin and flexible stranded stainless to which the pill electrode could be connected. steel wire with Teflon insulation. That was it. It could pace the heart. This created an opportunity to do a number of * * * * * things that couldn’t be done before. For exam- ple, a lot of patients can’t exercise due to age, in- Arzbaecher: The esophageal electrode gave firmity, obesity, and other reasons. Cardiac us the signal with which atrial arrhythmias could stress testing can be done by pacing the heart be instantly recognized. Atrial arrhythmias are rather than by exercising the patient. That was an not easy to recognize on the body’s surface. important development. Imaging studies such as Nebeker: Is this a recognition that comes echocardiograms could also be done. Tempo- through visual analysis by a cardiologist? rary esophageal pacing could be used to convert Arzbaecher: It’s computer recognition. The arrhythmias. Atrial flutter, especially in chil- algorithm looks at the esophageal signal, ana- dren, is easily converted by over-drive pacing. A lyzes it, and comes up with a rhythm diagnosis in short ten-second burst of temporary pacing from real time. The whole spectrum of cardiac arrhyth- the esophagus could convert the arrhythmia to mia can be detected, including atrial fibrillation, normal rhythm. atrial flutter, atrial tachycardia, premature atrial beats, and ventricular arrhythmias. * * * * * Our interest was in treating atrial arrhythmias with a Searle drug. I had the first half of that Arzbaecher: The dream of the drug pump problem solved, which was how to automati- people is the treatment of diabetes. A drug pump cally recognize the onset of an atrial arrhythmia with insulin to automatically treat the diabetic in a coronary care patient. patient would be a marvelous technology. Bil- Nebeker: Did you write programs to analyze the p-wave? Arzbaecher: Yes, my students and I wrote them. A student who helped with that was Janice Jenkins. She is now a professor at the University of Michigan and on leave from Michigan serv- ing as the program director of bioengineering at NSF.
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