Teo Te Wei - Pacing the Heart

Pacing the Heart: Growth and Redefinition of a Medical Technology, 1952-1975Author(s): Kirk JeffreySource: Technology and Culture, Vol. 36, No. 3 (Jul., 1995), pp. 583-624Published by: The Johns Hopkins University Press on behalf of the Society for the History of TechnologyStable URL: http://www.jstor.org/stable/3107242 .Accessed: 28/08/2011 20:07

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Pacing the Heart: Growth and Redefinition of a Medical Technology, 1952-1975 KIRK JEFFREY

A cardiac pacemaker delivers electrical impulses to the heart so as to coordinate the pumping action of the upper and lower chambers

(atria and ventricles) and speed the heart up from standstill or an

unduly slow rate.' Between 1952 and the mid-1970s, the practice of cardiac pacing grew from "promising report" to "standard procedure" and then kept on growing.2 The earliest devices stimulated the heart from outside the patient's body, but implanted pacemakers made their appearance at the end of the 1950s. The number of patients relying on pacemakers in the United States expanded to more than 150,000 by 1975.3 In the 1990s, estimating conservatively, 500,000-600,000 Americans carry pacemakers; more than 110,000

pacemakers are implanted annually in the United States by about

DR. JEFFREY is professor of history at Carleton College. He thanks Carleton College for research support through the Faculty Development Endowment. Professor Clifford E. Clark, Jr., and the Technology and Culture referees offered helpful criticism.

1 Its focus on slow heart rates (bradycardia, rates below sixty beats per minute) distin-

guishes the pacemaker from devices that use electrical shocks to halt unduly rapid heart rates (tachycardia) and random electrical behavior with consequent loss of organized beats (fibrillation). My definition of the pacemaker is time bound: as Victor Parsonnet and Alan D. Bernstein have observed, "The definition of a pacemaker is

imprecise, because now that word is applied to electrical stimulators that treat either slow or fast rhythms. In this computer age, a 'pacemaker' is essentially an implanted microcomputer that can be adapted noninvasively to any type of stimulation or sensing that is required." See Victor Parsonnet and Alan D. Bernstein, "Cardiac Pacing after 25 Years: A Practical Approach to Growing Complexity," in Modern Cardiac Pacing, ed. S. Serge Barold (Mount Kisco, N.Y., 1985), pp. 959-72, at 959. Cardiac electrostimulation is employed diagnostically (e.g., in an electrophysiology workup) as well as

therapeutically, but this article limits its scope to therapeutic uses of pacing. 2John B. McKinlay, "From 'Promising Report' to 'Standard Procedure': Seven Stages

in the Career of a Medical Innovation," Milbank Quarterly 59 (1981): 374-411. 3Victor Parsonnet and Marjorie Manhardt, "Permanent Pacing of the Heart: 1952

to 1976," American Journal of Cardiology 39 (1977): 250-56.

? 1995 by the Society for the History of Technology. All rights reserved. 0040-165X/95/3603-0004$0 1.00

583

584 Kirk Jeffrey

8,000 physicians.4 Pacing-related hardware, facilities, and services have cost Medicare well over $1 billion annually in recent years.5

A symbol in its early years of the fabulous promise of medical technology, pacing in the early 1980s became a lightning rod for doubts and concerns about the American system of health care. To- day, in a time of national debate about the cost and distribution of health care, a review of a success story involving high-tech medicine may help us understand one important underlying dynamic in the health-care system: the reciprocal and interactive process by which technological change and new concepts of disease stimulate each other, thereby creating a powerful momentum for growth.

A technological device draws us toward the outlook and aspirations of its sponsors, the groups that introduced it and shape its ongoing development and social meaning.6 Hence, this article speaks of pacing

4Because no national pacemaker registry existed during the period covered by this article, these and other figures must be taken as approximations. Here I follow the estimates of Parsonnet and his associates, who have conducted national surveys of pacing practices every few years since 1971: Alan D. Bernstein and Victor Parsonnet, "Survey of Cardiac Pacing in the United States in 1989," American Journal of Cardiology 69 (1992): 331-38. Their figure of 110,500 pacemakers implanted in 1989 (apparently misprinted as 117,000) included 89,445 primary (first-time) implantations and 21,055 replacements. But another set of observers suggests a figure of 250,000 implantations per year: Nicholas J. Stamato et al., "Permanent Pacemaker Implantation in the Car- diac Catheterization Laboratory versus the Operating Room," PACE (Pacing and Clini- cal Electrophysiology) 15 (1992): 2236-39.

5The Health Care Financing Administration reported 59,588 hospital discharges following the implantation of pacemakers in 1986-a suspiciously low number. Even so, considering that the likely cost of pacing over the remaining life of an elderly person ran to at least $30,000 in the late 1980s, then an annual cohort of 60,000 Medicare pacemaker candidates would represent future direct pacing-related costs of some $1.8 billion (U.S. Health Care Financing Administration, Office of Research and Demonstrations, Health Care Financing: Special Report: Hospital Data by Geographic Area

for Aged Medicare Beneficiaries: Selected Procedures, 1986 [Baltimore, June 1990], 2:77). Indirect costs to the health-care system are much more difficult to estimate. On the one hand, because they live longer, people carrying pacemakers incur other medical costs that they would not have incurred before the era of pacing. On the other hand, they are better able to care for themselves, less likely to require long-term care, and at a greatly reduced risk of cardiac arrest with its attendant emergency procedures (cardiopulmonary resuscitation, ambulance, intensive care) or of major fractures from falls. For a general discussion of the cost-effectiveness of cardiac pacing, see Richard Sutton and Ivan Bourgeois, Foundations of Cardiac Pacing, Part I (Mount Kisco, N.Y., 1991), pp. 303-13.

6Compare Susan E. Bell's remark that a technology is "the product or embodiment of human activity": Susan E. Bell, "A New Model of Medical Technology Development: A Case Study of DES," Research in the Sociology of Health Care 4 (1986): 1-32, at 2. On the concept of sponsorship, see Ron Westrum, Technologies and Society (Belmont, Calif., 1991), pp. 171-93.

Pacing the Heart 585

more often than the pacemaker. Pacing is an emerging medical sub-

specialty with its own textbooks, professional organizations, journals, conventions, and competency examination.7 More broadly still, pacing has grown into a subculture complete with creation myths; revered elders; complex networks of friendship and rivalry encom-

passing physicians, business executives, and engineers; and a distinctive language bewildering to the outsider.

To understand fully cardiac pacing, one should follow developments in pacemaker hardware, techniques of implantation, medical

understanding of heart arrhythmias, the rise of the medical-device

manufacturing industry, and the policies of governments toward the

consumption of pacing devices and services. It is not an exclusively American story: research and inventive activity in western Europe, Canada, and Japan have contributed in important ways to the growth and redefinition of cardiac pacing. This article has more modest aims: it limits its scope to the shifting roles of heart surgeons and cardiolo-

gists in the United States during the first quarter century of cardiac

pacing, an era of explosive growth and repeated technological redefinition.8 Doctors played several parts, acting sometimes as technol-

ogists who invented and advocated new pacing hardware and tech-

niques, sometimes as practitioners who applied the technology of

pacing to real patients. Some doctors also served as advance scouts

7Seymour Furman et al., A Practice of Cardiac Pacing, 3d ed. (Mount Kisco, N.Y., 1993), is one of several current texts; J. Warren Harthorne et al., "North American Society of Pacing and Electrophysiology (NASPE)," PACE 2 (1979): 521-22; Pace- maker Study Group, "Optimal Resources for Implantable Cardiac Pacemakers," Circu- lation 68 (1983): 227A-244A; J. Warren Harthorne and Victor Parsonnet, "Training in Cardiac Pacing," Journal of the American College of Cardiology 7 (1986): 1213-14;

Seymour Furman, Editorial: "Certificate of Special Competence in Cardiac Pacing," PACE 9 (1986): 1; Victor Parsonnet, "Cardiac Pacing as a Subspecialty," American Journal of Cardiology 59 (1987): 989-91. The leading journal in the field, PACE, was founded in 1978.

8An arrhythmia is a deviation from normal heart rhythm. I use the terms doctor and physician as synonyms referring to persons holding the M.D. degree and licensed to practice medicine. Thoracic (chest) surgery emerged as an informal surgical subspecialty in the 1930s, with board certification dating from 1950. The term cardiothoracic (heart and chest) surgery came into use during the 1950s. Cardiology was formally created as a subspecialty of internal medicine in 1940. Cardiologists attend to diseases of the heart and vascular system; they employ invasive procedures such as catheterization but are not certified to perform heart surgery. Rosemary Stevens, American Medi- cine and the Public Interest (New Haven, Conn., 1971), is the classic study of medical specialization in the United States; see also Joel D. Howell, "The Changing Face of Twentieth-Century American Cardiology," Annals of Internal Medicine 105 (1986): 772-82.

586 Kirk Jeffrey

who identified new heart arrhythmias that might be suitable for treatment through pacing.9

Cardiac pacing proved itself an extraordinarily flexible technology-it successfully managed chronic diseases not even defined when Paul M. Zoll announced his external pacemaker in 1952.10 Doctors' understanding of "cardiac pacing" repeatedly changed as medical researchers repeatedly framed new heart arrhythmias for which pacing has seemed the appropriate therapy. Knowledge gained in the laboratory was passed to clinicians who, in turn, informed biomedical engineers of new needs and opportunities for pacing that required new pacing hardware.1l The very success of clinical cardiac pacing stimulated further basic research into conduction disorders of the heart, bringing the process of transmission of knowledge full circle.

This account of the invention of effective heart pacemakers and the development of pacing as a practical therapy thus asks what cardiac pacing has meant, principally to the surgeons and cardiologists who examined patients and implanted pacemakers, at different mo- ments in the early history of the field. It highlights several episodes of substantial redefinition in which significant expansions of the list of medical indications for pacing occurred. It describes the field of cardiac pacing at the end of the 1950s and 1960s and notes the organizational forces shaping the field in each decade, for physicians who specialized in pacing never made choices in a vacuum. The early expansions of the meaning of cardiac pacing prepared the field for rapid growth once Medicare was in place. One might expect that the centrality of an artifact, the pacemaker, would endow pacing with a less evanescent character. Not so: the meaning of terms like "pacing" and "pacemaker" had been so thoroughly transformed that what they

9Federal regulation can be dated from passage of the Medical Device Amendments of 1976 (amendments, i.e., to the Food, Drug, and Cosmetic Act of 1938, which had created the Food and Drug Administration). My attention to "streams of activity" shaping the technology of pacing owes much to Bell, "A New Model" (n. 6 above), and to Joel D. Howell, "Early Perceptions of the Electrocardiogram: From Arrhythmia to Infarction," Bulletin of the History of Medicine 58 (1984): 83-98, and "Diagnostic Technologies: X-Rays, Electrocardiograms, and CAT Scans," Southern California Law Review 65 (1991): 529-64.

0lOn artifactual flexibility, see Wiebe E. Bijker, "The Social Construction of Bakelite: Toward a Theory of Invention," in The Social Construction of Technological Systems, ed. Wiebe E. Bijker, Thomas P. Hughes, and Trevor Pinch (Cambridge, Mass., 1987), pp. 159-87; and Howell, "Diagnostic Technologies."

"A clinician is any doctor who engages in the practical work of observing and treating patients (clinical practice), as distinguished from laboratory research or theo- retical study.


signified by the mid-1970s bore little resemblance to the definitions and assumptions of twenty years earlier.

Pacing for Emergency Resuscitation, 1952

Although there had been some earlier experiments with pulsed electrostimulation to resuscitate human beings from standstill of the heart, cardiac pacing as a set of systematic medical procedures origi- nated in the 1950s.12 Zoll, a cardiologist at Beth Israel Hospital in Boston, invented an external pacemaker and reported having used it to revive a patient in 1952. Zoll's approach to pacing the heart was impressive for its simplicity and directness: the pacemaker consisted of off-the-shelf components including a plug-in electrical stimulator familiar to most doctors from their student days and simple needle electrodes inserted beneath the skin of the patient's chest on either side of the heart. (Zoll later substituted standard electrocardiograph electrodes that were strapped to the chest.) Electrical impulses of two milliseconds' duration, fired through the chest with an amplitude of 50-150 volts, would stimulate the ventricles to contract, thereby restoring a circulation of blood to the brain and the body. Zoll's first publication announced that this pacemaker had managed the heartbeat in an elderly patient for fifty-two consecutive hours.13

External pacing came into widespread use in American hospitals

12 Kirk Jeffrey, "The Invention and Reinvention of Cardiac Pacing," Cardiology Clinics 10 (1992): 561-71, argues that the basic scientific and technical knowledge required for building simple pacemakers and pacing the heart for brief periods of time existed

by the 1920s. However, chronic arrhythmias and "sudden cardiac death" (death within 24 hours from a heart attack or cardiac arrest) had not yet been defined as critical and solvable problems by physicians specializing in diseases of the heart. Working sepa- rately, physician-inventors in Australia and New York had actually invented pacing devices in the mid-1920s and early 1930s, but their work received little attention and no support from the medical community. The situation had changed considerably by the late 1940s as a result of many factors: improved understanding of arrhythmias, experience with open-chest defibrillation, rising physician confidence about working around and even within the exposed human heart, and the postwar redefinition of the hospital as a technological center for the delivery of acute-care medicine.

13Paul M. Zoll, "Resuscitation of the Heart in Ventricular Standstill by External Electric Stimulation," New EnglandJournal of Medicine 247 (1952): 768-71. An electrical

impulse delivered to a single point in the myocardium (the muscular tissue of the

heart) will be propagated from cell to cell. This depolarization results in mechanical contraction of the heart muscle. The energy required to instigate this process is quite small, on the order of 10-50 microjoules, if delivered directly to the excitable tissue. Zoll's external pacing system required a high voltage because of the impedance associated with the patient's skin and subcutaneous tissues, the surface area of the electrodes, the short pulse duration, and other factors. In modified form, short-term external

pacing remains a widely used hospital technology.

588 Kirk Jeffrey

during the 1950s.14 But this was not pacing as the public knows it today: Zoll's invention carried with it a set of assumptions and practices quite different from those now associated with implanted cardiac

pacemakers. This first version of pacing meant emergency resuscitation in the hospital from ventricular standstill. A pulse generator the size of a breadbox that plugged into the alternating current (AC) electrical

system implied a bedridden patient. The high voltage required to

capture the heartbeat implied very short bouts of pacing-from minutes to hours-and patients who were unconscious or sedated. Zoll's famous patient R. A. had been able to eat, sleep, and carry on conver- sation during treatment with the pacemaker, but this was uncommon; the artificial pulses caused painful muscle contractions in the upper chest that most patients found difficult to tolerate.'5

Zoll invented his pacemaker to address an uncommon occurrence known as a Stokes-Adams attack, a potentially lethal complication of

complete heart block. In heart block, the heart's natural electrical

signal that triggers atrial and then ventricular contraction starts out in normal fashion from the sinus node, its source high in the right atrium; when the impulse reaches the floor of the right atrium, conduction cells within the heart muscle fail to propagate it on to the ventricles, the major pumping chambers of the heart. One of several

secondary "pacemakers" below the site of the block may then stimulate the ventricles to contract; but these backup pacemakers fire more

slowly than the normal one, and because of the block the atrial and ventricular contractions no longer occur in a coordinated man- ner.16 (See fig. 1.)

14 The device was put into commercial production by Electrodyne, a small electronics firm outside Boston. Morris J. Nicholson et al., "A Cardiac Monitor-Pacemaker: Use

during and after Anesthesia," Anesthesia and Analgesia 38 (1959): 335-47, gives a con-

temporary description. For a full discussion of the technical issues, see Pierre J. Birkui et al., eds., Noninvasive Transcutaneous Cardiac Pacing (Mount Kisco, N.Y., 1992).

External pacemakers introduced in the 1980s have greatly reduced this problem: Jerry C. Luck and Michael L. Martel, "Clinical Applications of External Pacing: A Renaissance," PACE 14 (1991): 1299-1316.

16 Heart block is also known as atrioventricular or AV block. Cardiologists then and now distinguish three stages in the development of the condition. In first-degree block, signals reach the ventricles after a delay; in second-degree block, some signals reach the ventricles while others do not. The text describes third-degree or complete block. See Johan Landegren and Gunnar Biorck, "The Clinical Assessment and Treatment of Complete Heart Block and Adams-Stokes Attacks," Medicine 42 (1963): 171-96. For a historical treatment of medical understanding of heart block, see David C. Schechter et al., "History of Sphygmology and of Heart Block," Diseases of the Chest 55, suppl. 1

(June 1969): 535-79. Physiologists believed that most cases were a result of coronary artery disease; heart block was also known to be an occasional sequel to heart attack: C. K. Friedberg et al., "Nonsurgical Acquired Heart Block," Annals of the New York


The person with heart block may not be able to tolerate physical activity and may show symptoms of congestive heart failure. Sooner or later, the person may also begin to experience brief episodes of dizziness or unconsciousness from inadequate cerebral circulation. Eventually the circulation of blood may cease as the ventricles go into fibrillation (uncoordinated quivering) or come to a standstill. Loss of consciousness resulting from heart block was called a Stokes-Adams attack, and mean life expectancy from the first such attack was known to be a matter of months because sooner or later an episode would last long enough to kill the patient.17 Promptly applied, the Zoll pacemaker maintained a circulation through the few minutes of a Stokes- Adams attack that took the form of ventricular standstill.'8 Pacing thus began as an emergency procedure; it resembled the use of in- hospital defibrillation today. But at first Zoll did not conceive of pacing as a possible way to manage the underlying degenerative disease, complete heart block.

Pacing for Postsurgical Heart Block, 1958

The earliest transformation of pacing came quickly: in the mid- 1950s a new group of users, the first open-heart surgeons, decided that cardiac pacing might solve a hitherto unknown complication they were encountering. In adapting Zoll's original idea to their needs, the surgeons invented a second variety of short-term pacing.

The early open-heart operations were often performed on children born with congenital defects and known as "blue babies." By early 1957, C. Walton Lillehei's surgical group at the University of Minne- sota had carried out 305 open-heart operations but had discovered that approximately one child out of ten developed complete heart block as a consequence of the surgery. The surgeons concluded that

Academy of Sciences 111 (1964): 835-47. The intense research on conduction diseases that got under way with the invention of cardiac pacing also demonstrated that with

age, the specialized conduction fibers could gradually degenerate and lose the capacity to repolarize: Michael Davies and Alan Harris, "Pathological Basis of Primary Heart Block," British Heart Journal 31 (1969): 219-26.

17 MArten Rosenqvist and Rolf Nordlander, "Survival in Patients with Permanent Pacemakers," Cardiology Clinics 10 (1992): 691-703.

18Zoll held that the great majority of Stokes-Adams attacks took the form of standstill, but this was a contested point. Ventricles in fibrillation would have to be brought to standstill by means of a strong shock before effective pacing could begin; by itself, a pacemaker would be ineffective in such a case. Since the 1950s the term Stokes- Adams disease has fallen into disuse. For an authoritative latter-day discussion I have relied on Douglas P. Zipes, "Specific Arrhythmias: Diagnosis and Treatment," in Heart Disease, ed. Eugene Braunwald, 4th ed. (Philadelphia, 1992), pp. 667-725, esp. pp. 710-15.

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FIG. 1.-Electrocardiogram of complete heart block showing complete dissociation of atrial activity (P waves) from ventricular (QRS com-

plexes). Elapsed time from one heavy vertical line to the next is 0.2 second. The P-P intervals indicate an atrial rate of about 50-60 beats per

minute, while the intervals between QRS complexes indicate a ventricular rate of 35 beats per minute. (Kevin R. Brown and Sheldon Jacobson,

Mastering Dysrhythmias: A Problem-Solving Guide [Philadelphia, 1988], p. 238; reprinted courtesy of F. A. Davis Co.)

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they were occasionally disrupting the heart's conduction pathways while repairing defects in the ventricular septum, the partition between the right and left ventricles. The complication almost always killed the patient.'9

Short-term pacing seemed an obvious way to manage this problem; but with postsurgical heart block it would be necessary to pace a child's heart steadily for days or weeks to give the specialized conduction cells of the heart time to heal. The Zoll pacemaker seemed more appropriate for brief and occasional bouts of pacing. Certainly, young children could not tolerate the high pacing voltages without sedation. The group at Minnesota therefore began to sew a stainless steel wire, coated with Teflon except at its tip, into the wall of the ventricle (the myocardium) during open-heart surgery. They would bring the wire out through the surgical wound, bury a second wire under the patient's skin as an indifferent electrode, and connect both to a Zoll pulse generator.20 Days later, the surgeon could pull gently on the wire and dislodge it from the myocardium. By the fall of 1957, Lil- lehei was following this procedure whenever a patient showed signs of block during an open-heart operation.21

Since the myocardial pacing wire could capture control of the heartbeat at a voltage level at least one order of magnitude lower than external pacing,22 the patient could remain painlessly dependent on it for days or weeks. But the pulse generator was still a large device

19Leonard G. Wilson, Medical Revolution in Minnesota: A History of the University of Minnesota Medical School (St. Paul, Minn., 1989), pp. 516-19; Dwight C. McGoon et al., "Surgically Induced Heart Block," Annals of the New York Academy of Sciences 111 (1964): 830-34; interview with C. Walton Lillehei, St. Paul, Minnesota, July 25, 1990. Blue babies were so called because inadequate oxygenation of the blood imparted a bluish cast to their skin.

20All pacemakers consist of three elements: a pulse generator, electrodes (electrical conductors through which a current enters or leaves a medium such as heart tissue), and a lead (one or more insulated wires connecting the pulse generator to the electrode). In the pacemaker invented at the University of Minnesota, the tip of the myocardial wire was the electrode; the wire itself, the lead. This article, like all writings on cardiac pacing, speaks of "the atrium" and "the ventricle" as if a human being had

only one of each. In fact it is necessary to deliver a pacing impulse only to the chambers on one side of the heart since the cells of the myocardium will propagate it to the other.

21William L. Weirich et al., "The Treatment of Complete Heart Block by the Com- bined Use of a Myocardial Electrode and an Artificial Pacemaker," Surgical Forum 8 (1958): 360-63; C. Walton Lillehei et al., "Direct Wire Electrical Stimulation for Acute

Postsurgical and Postinfarction Complete Heart Block," Annals of the New York Academy of Sciences 111 (1964): 938-49; Wilson, pp. 516-19; Lillehei interview.

22 Lillehei's surgical team reported capture at output voltages in the range of 1.5-4.5 volts: Weirich et al., p. 362.

592 Kirk Jeffrey

FIG. 2.-C. Walton Lillehei with a young patient, Saturday Evening Post, March 4, 1961, p. 13. The boy is wearing an external pulse generator, the Medtronic 5800. The two output terminals protrude from the top of the device. One of the knobs on the front controls electrical output, the other the pacing rate. For a full description, see C. Walton Lillehei et al., "Transistor Pacemaker for Treatment of Complete Atrioven- tricular Dissociation," Journal of the American Medical Association 172 (1960): 2006-10. (Photo courtesy of Medtronic, Inc.)

plugged into the AC electrical system. The surgeons at Minnesota wished to get their child-patients out of bed and moving around; they worried that an electrical malfunction could send a patient into ventricular fibrillation (VF), a lethal arrhythmia. Lillehei therefore asked an engineer who repaired electronic equipment at the medical school, Earl Bakken, if he could make a small battery-powered pulse generator. Delivered early in 1958, Bakken's new device was powered by flashlight batteries and employed newly available components called transistors. Small enough to hold in the hand, it could be carried in a pouch or holster worn at the belt or around the neck (fig. 2). The small firm that Bakken and his brother-in-law had founded, Medtronic, Inc., soon began to produce the units in response to re-

quests from surgeons around the United States. This early experience in pacing prepared the firm to grow along with the growth of cardiac


pacing. Medtronic soon became the world's largest manufacturer of

pacemakers, a position it still holds today.23

Pacing in the 1950s: Treatment for Acute Illness

Lillehei's myocardial approach to the heart emerged as an offshoot of the revolution in heart surgery, but it still bore a strong resemblance to Zoll's original version of pacing. In both external and myocardial pacing, the patient was assumed to be gravely ill, confined to the hospital, and pacemaker-dependent. Both systems ministered to acute crises, whether Stokes-Adams attacks or postsurgical heart block. In both, the pacemaker was defined as a piece of hospital equipment; its transformation into a more or less permanent addition to the patient's own body was still a few years away.24

It might be asked why physicians chose cardiac electrostimulation to drive the heart rather than some entirely different technology- perhaps the administration of stimulating drugs such as atropine or

isoproterenol. Researchers had experimented since the 1920s with

drugs that stimulated the heart; while these were often effective for brief intervals in particular patients, it proved extremely difficult to administer an appropriate amount of a drug at a steady rate, hour after hour and day after day. More broadly, by the postwar years doctors had grown accustomed to thinking of the heart as an electro- mechanical system, a "pump" activated by electrical impulses that the specialist could comprehend by analysis of the electrocardiogram (ECG).25 Investigators of the 1950s such as Zoll and Lillehei knew of the new technique of open-chest defibrillation, a form of electrostimulation that bore an obvious resemblance to pacing and had resusci- tated human beings from VF beginning in 1947. Then too, by good fortune complete heart block happened to be the perfect "electrical failure" to take up: it could be managed effectively in many cases by means of a device that was straightforward in concept. The pioneers in cardiac pacing were able to gain hands-on experience while using

23For a definition of fibrillation, see n. 1 above. See also C. Walton Lillehei et al., "Transistor Pacemaker for Treatment of Complete Atrioventricular Dissociation," Journal of the American Medical Association 172 (1960): 2006-10; Wilson, pp. 519-21; and Lillehei interview. Steven M. Spencer, "Making a Heartbeat Behave," Saturday Evening Post, March 4, 1961, pp. 13 ff., gives an interesting popular account of pacemaker development that includes interviews with several of the early patients.

24Jeffrey, "Invention and Reinvention" (n. 12 above). 25Christopher Lawrence, "Moderns and Ancients: The 'New Cardiology' in Britain,

1880-1930," Medical History, suppl. 5 (1985): 1-33; Howell, "Early Perceptions of the

Electrocardiogram (n. 9 above); Lynn Payer, Medicine and Culture (New York, 1988), pp. 74-75, 79-85.

594 Kirk Jeffrey

relatively simple devices that did not require sensing as well as pacing functions or produce complex electrocardiograms. While attempts to control heart block with drugs ran into repeated problems, the

pacemakers of the late 1950s and early 1960s could quickly boast a number of remarkable success stories. And doctors are much influenced by case histories.26

Physician-inventors and the electronic engineers who advised and worked with them were clearly the dominant influences on the na- scent field of pacing, its "sponsors." By necessity, pacing at first remained largely confined to major hospitals; but it began to spread in the late 1950s and early 1960s as part of a package that included thoracic surgery and acute cardiac care.27 With its operating rooms, catheterization labs, and skilled nursing care, and with procedures such as electrocardiography, AC defibrillation, and cardiac catheterization, the large hospital had already emerged by the mid-1950s as the appropriate locus for the practice of acute-care medicine relating to the heart. Pacing was not only nurtured in the hospital, but it

promised to reinforce the hospital's role in the acute care of heart disease.28

These institutional and technological developments took place in a cultural climate that encouraged an activist, experimental approach in cardiology and heart surgery. Cheered by the dramatic achieve- ments of military medicine during World War II, the American pub-

26On pharmacologic control of cardiac arrhythmias, see Paul B. Beeson, "Changes in Medical Therapy during the Past Half Century," Medicine 59 (1980): 79-99. Lil- lehei's group at Minnesota tried to manage seven cases of postsurgical heart block with epinephrine, aphedrine, atropine, and sodium lactate in 1954-55; they had no survivors. They then switched to isoproterenol (Isuprel) in 1955-57; out of nineteen

cases, they had nine successes, five that remained in complete block, and five deaths. Results like this drove doctors very quickly to electrostimulation. See Lillehei et al., "Direct Wire Electrical Stimulation" (n. 21 above). Defibrillation terminates the random electrical activity of a fibrillating heart by means of a strong electrical shock. At first, doctors applied paddle electrodes directly to the exposed heart: Claude S. Beck et al., "Ventricular Fibrillation of Long Duration Abolished by Electric Shock," Journal of the American Medical Association 135 (1947): 985-86.

27Paul M. Zoll, "The Cardiac Monitoring System" (interview), Medical News 186

(1963): 34-36; Bernard Lown, "Intensive Heart Care," Scientific American 219 (July 1968): 19-27; Louise B. Russell, Technology in Hospitals (Washington, D.C., 1979), pp. 41-70.

28 Russell; Paul Starr, The Social Transformation of American Medicine (New York, 1982);

Joel D. Howell, "Machines and Medicine: Technology Transforms the American Hos-

pital," in The American General Hospital: Communities and Social Contexts, ed. Diana Eliza- beth Long and Janet Golden (Ithaca, N.Y., 1989), pp. 109-34; Rosemary Stevens, In Sickness and in Wealth: American Hospitals in the Twentieth Century (New York, 1989), pp. 224-32; Jeffrey, "Invention and Reinvention" (n. 12 above).


lic supported medical research and looked forward to rapid success in the "war" against heart disease.29 David Sarnoff, chairman of the board of the Radio Corporation of America and a noted technological sage, probably captured the enthusiasm of many in picturing a future time when "miniaturized electronic substitutes will be developed to serve as long-term replacements for organs that have become defec- tive through injury or age.... It is not too far-fetched to imagine a man leading a normal life with one or more vital organs replaced by the refined substitutes of the future."30

In spite of such optimism, we should not overstate the centrality of cardiac pacing: to all but its sponsors, pacing at the end of the 1950s had the look of an intriguing but distinctly marginal new tech-

nology of medicine. Although postsurgical heart block had added hundreds of new patients to the number who might be assisted by pacing, the total population with Stokes-Adams disease or postsurgical block appeared small to most clinicians.31 The management of electrical blockages in the heart might intrigue researchers, but commercial prospects did not look particularly inviting. When representa- tives from major manufacturing firms began to inquire about the market for pacemakers in the late 1950s, pioneers in the field gave them estimates on the order of five hundred units per year for the United States. Such figures were probably based on the assumption that a handful of external pulse generators, whether plug-in or

29U.S. Office of Scientific Research and Development, Committee on Medical Re- search, Advances in Military Medicine (Boston, 1948); President's Commission on the Health Needs of the Nation, Building America's Health (Washington, D.C., 1952); Starr, pp. 335-51; Eugene Braunwald, "The Golden Age of Cardiology," in An Era in Cardio- vascular Medicine, ed. Suzanne B. Knoebel and Simon Dack (New York, 1991), pp. 1-4.

30"Sarnoff Predicts 'Disease Machine,'" New York Times (November 11, 1959), p. 28. Sarnoff added, "One day artificial kidneys, lungs, and even hearts may be no more remarkable than artificial teeth." Sarnoff had predicted in 1916 that the radio would become a "household utility."

311 have found no direct discussions of the incidence of heart block or Stokes-Adams disease from the period before 1960. Early investigators in cardiac pacing whom I have interviewed all agree that estimates of the size of the prospective patient population were minuscule and that clinicians saw very few cases in their careers because

complete heart block often terminated in death from cardiac arrest before a person could see a physician. My impression is that the question of how many people had heart block received little attention until after implantable pacemakers arrived on the scene. Estimates then began to become both more precise and larger. See, e.g., Friedberg et al. (n. 16 above), p. 846. The most exhaustive study of the incidence of heart block conducted during the period covered in this article is David B. Shaw and Christopher A. Kekwick, "Potential Candidates for Pacemakers," British Heart Journal 40 (1978): 99-105. Shaw and Kekwick estimated the incidence of diagnosed cases of heart block in their study area (Devon, England) at 97 per million population.

596 Kirk Jeffrey

battery powered, could serve the needs of dozens or hundreds of patients over a few years because the pacemaker was a piece of hospital equipment, not (yet) a part of the patient's own body. This misper- ception ensured that larger companies would leave the market to small specialty firms, such as Electrodyne and Medtronic, that had already developed relationships with medical research teams.32

An Implantable Pacemaker for Chronic Heart Block

In the late 1950s, a second and more thoroughgoing redefinition of cardiac pacing got under way when a few physician-inventors began to think of pulsed electrostimulation as a way to solve the long- term problem of chronic complete heart block by permanently sup- planting the heart's own failed conduction system.33 This meant that the patient would receive electrical stimulation not for a few days or weeks but for months and years-ideally, for the rest of a lifetime. Long-term pacing implied that the patient need not be confined to a hospital bed but might become fully ambulatory, leave the hospital, and lead the life of a semi-invalid. Rather than a brief and occasional intervention, pacing would now become a permanent circumstance in the life of each patient. Although no pioneers in pacing had yet recognized it, long-term pacing also meant that the pacemaker would require some kind of routine follow-up management through an outpatient facility.

This revised version of cardiac pacing did not emerge naturally and directly from existing practices but instead required that doctors radically reorganize their thinking. Indeed, some physicians involved with pacing remained committed to the earlier concept of the pacemaker as an emergency or short-term instrument.34 Certainly the new version of cardiac pacing entailed radical changes in the design of pacing technology and in the activities surrounding its use. As an

32Telephone interview with Sam E. Stephenson, Jr., August 30, 1991. According to Bakken, the market-research firm Arthur D. Little estimated in 1960 that "the world- wide, all-time market for pacemakers would be about ten thousand units": interview with Earl E. Bakken, Fridley, Minnesota, May 23, 1990.

33This revised concept of pacing occurred to several research groups beginning around 1955-56; I have not tried to award priority for the idea to any group in

particular. 34 Several of the researchers who at first failed to grasp the idea of long-term pacing

had earlier worked with defibrillation, perhaps the quintessential example of an acute- care technology; this experience dominated their perceptions of the pacemaker. Some viewed the pacemaker almost as if it were a kind of defibrillator. See the discussion at the "Rockefeller Conference," September 1958, as excerpted in Kirk Jeffrey, ed., "The Conference on Artificial Pacemakers and Cardiac Prosthesis, 1958," PACE 16 (1993): 1445-82. Joel D. Howell found an analogous pattern in early constructions of the

meaning and utility of the ECG: Howell, "Early Perceptions of the Electrocardiogram" (n. 9 above).


unanticipated result, the new formulation also prepared the way for a vast increase in the manufacture and use of pacemakers.

The idea for long-term pacing was "in the air" by about 1956, and researchers debated its feasibility at a one-day conference in September 1958. Zoll explained that resuscitating patients from Stokes-Adams attacks represented no solution to the underlying problem of heart block; in a vivid presentation, he made the case for fundamentally redefining the function of cardiac pacing: "After the initial excitement of saving the patient from the initial episode of standstill, everybody relaxes and you come back later ... and find the patient had another episode.... You can resuscitate a patient... if you are ready all the time for the rest of the patient's life, and that is a big order." 35

Just such a situation arose in St. Paul, Minnesota, in March 1959, when Samuel Hunter, a surgeon who had done a residency with Lil- lehei, was presented with an unexpected case, a 72-year-old man in complete heart block and suffering dozens of Stokes-Adams attacks daily. Rather than restarting the heart time and again by means of an external pacemaker, Hunter opened the patient's chest and sutured an experimental bipolar pacing electrode, never before used with a human subject, to the ventricular myocardium. "The patient was not anesthetized but was essentially dead when we brought him to the operating table," Hunter later recalled. "We just kind of kept his heart going by pounding his chest." Engineer Norman Roth attached the lead to one of the new battery-powered external pulse generators. "A lot of other people were in the room, and when it started I just couldn't believe my eyes. Because it's one thing [to have] a nice little compact heart in a child; but this was a 72-, 73-year-old man with a big bulbous heart that was kind of like a big jellyfish in there, sort of semi-blue; and all of a sudden it started to pump, vigorously and according to the rate that we wanted, and we could control it, and all of a sudden he starts to wake up! So we had to put him to sleep and finish the operation. I don't know what I said; someone said, 'My God, it worked!"'36 Hunter's patient

35Jeffrey, ed., p. 1450. The debates at this meeting are analyzed in Kirk Jeffrey, "The Next Step in Cardiac Pacing: The View from 1958," PACE 15 (1992): 961-67. Of Zoll's first fourteen pacing cases as reported in 1954, eight had died from later Stokes-Adams attacks after an initial successful resuscitation via the pacemaker. See Paul M. Zoll et al., "Treatment of Stokes-Adams Disease by External Electric Stimula- tion of the Heart," Circulation 9 (1954): 482-92.

36Interview with Samuel W. Hunter, Mendota Heights, Minn., November 30, 1989. Hunter also reported that the patient, Warren Mauston, would allow the surgeon to turn off the external pulse generator to demonstrate its functioning for visiting cardiologists. Mauston would slip into unconsciousness within a few seconds, "then I'd

snap it on again, and he'd come right out of it. I did that several times. I had a lot of

598 Kirk Jeffrey

lived in good health for nine more years, dependent on his pacemaker the entire time. A reporter wrote that "although he occasionally frets at being unable to go out on the golf course as he used to, he putts on the living-room rug..., gets up and downstairs and walks around the neighborhood."37

This case, which had arisen as a clinical emergency rather than as part of a research program, was one of several around 1959-60 to demonstrate that it was possible to pace the heart over an extended period and send the patient home.38 By 1959 several research teams were already experimenting with new kinds of pacemakers that would be more suitable for long-term use. Most of the new designs contemplated an implanted, battery-powered pulse generator to elim- inate a major source of infection, the pacing wire that came through the patient's chest. A fully implanted device would also ensure that the doctor retained complete control of the pacemaker by putting it where the patient could not touch it. However, implanting the pulse generator implied that the patient must undergo future surgical procedures when the battery ran low.

By now, research groups in the United States and Europe were

racing to come up with a practical long-term pacing device. Teams in Stockholm and London implanted several pacemakers manufac- tured by the Swedish firm of Elema-Shonander between 1958 and

early 1960. The Elema pulse generator was rechargeable by an induc- tion coil placed on the patient's body. This device had technical problems, and in 1961 the company introduced a successor with mercury cells. Around the same time, a group at Yale University experimented with a radio frequency pacemaker that included an implanted re- ceiver attached to the pacing electrodes, and an external transmit- ter-a setup that exteriorized the battery.39

[ECG] tracings. I had those all over the laboratory-Mr. Mauston sliding toward eter-

nity because I'd turned off his pacemaker." 37Samuel W. Hunter et al., "A Bipolar Myocardial Electrode for Complete Heart

Block," Journal-Lancet 79 (1959): 506-8; David C. Schechter, "Background of Clinical Cardiac Electrostimulation. VII. Modern Era of Artificial Cardiac Pacemakers," New York State Journal of Medicine 72 (1972): 1176-81; Spencer (n. 23 above); interview with Hunter. The electrode was an experimental model developed by Norman Roth, an

engineer at Medtronic. 38Prior to Hunter's case, the longest episode of pacing had probably involved a

patient at Montefiore Hospital in the Bronx who had been intermittently pacemaker- dependent (and hospital-bound, though ambulatory) for ninety-six days in the fall of 1958. See Seymour Furman and John B. Schwedel, "An Intracardiac Pacemaker for Stokes-Adams Seizures," New England Journal of Medicine 261 (1959): 943-48. This case is discussed below.

39A. H. M. Siddons and O'Neal Humphries, "Complete Heart Block with Stokes- Adams Attacks Treated by Indwelling Pacemaker," Proceedings of the Royal Society of Medicine 54 (1961): 237-38; Rune Elmqvist, "Review of Early Pacemaker Develop-


In June 1960, at the Veterans Administration (V.A.) Hospital in Buffalo, New York, an elderly man received the first successful fully implanted pacemaker. Designed by electrical engineer Wilson Greatbatch, it was implanted by William Chardack, a surgeon.40 The Chardack-Greatbatch pacemaker, licensed to Medtronic and modified in various ways, quickly set the standard for cardiac pacemakers in the United States. The first version to reach the market contained

only eight circuit components including two junction transistors. The

pulse generator, slightly larger than a pocket watch, encapsulated the

circuitry and a mercury-cell battery in silicone rubber. Devices of this

generation were known as asynchronous, fixed-rate pacemakers: they had no capacity to sense electrical activity within the heart and could not vary impulse rate or amplitude; they simply fired at a preset rate such as 70 impulses per minute.41 But the Chardack-Greatbatch

pacemaker was a wonder for its time. After several early failures from broken wires, Chardack designed a coiled-spring lead that proved remarkably reliable.42 (See fig. 3.)

Inventing permanent cardiac pacing involved not only the device but the surgical procedure. Implantation of a pacemaker in the 1960s qualified as major surgery; it was Chardack who created the technique. Working in an operating room on a fully anesthetized patient, the sur-

geon created a pocket beneath the skin in the patient's left abdomen as a site for the pulse generator. He then made a large chest incision and

ment," PACE 1 (1978): 535-36; William W. L. Glenn et al., "Remote Stimulation of the Heart by Radiofrequency Transmission," New England Journal of Medicine 261 (1959): 948-51. The "main line" of development, as described in the text, was pursued in the late 1950s by Zoll, William Chardack, and other teams, with Chardack's group announcing the first successful clinical case, an important symbolic milestone in the

eyes of physicians. 40William M. Chardack et al., "A Transistorized, Self-Contained, Implantable Pace-

maker for the Long-Term Correction of Complete Heart Block," Surgery 48 (1960): 643-54; Wilson Greatbatch, "Twenty-Five Years of Pacemaking," PACE 7 (1984): 143-47. The group employed hunt-and-try tactics to solve the two crucial problems they encountered: protecting the battery and circuitry from body fluids while permit- ting the diffusion of hydrogen gas, a by-product of the nickel-cadmium battery chemis-

try, and finding a lead system able to withstand approximately 31.5 million flexions

per year from the motion of the beating heart without breaking or causing a lesion in the heart wall. Chardack's group did not learn of Ake Senning's work in Stockholm until just before the first clinical use of their implanted pacemaker. See William M. Chardack, "Recollections- 1958-1961," PACE 4 (1981): 592-96.

41 The most complete review of these early pacemakers is William M. Chardack et al., "Clinical Experience with an Implantable Pacemaker," Annals of the New York Academy of Sciences 111 (1964): 1075-92.

42William M. Chardack, "A Myocardial Electrode for Long-Term Pacemaking," An- nals of the New York Academy of Sciences 111 (1964): 893-906. The first patient, Frank Henefelt, is interviewed in Spencer (n. 23 above).

600 Kirk Jeffrey

FIG. 3.-The Medtronic 5850, a Chardack-Greatbatch implantable pacemaker from about 1963, showing the coiled-spring lead and myocardial electrodes invented by William Chardack. The pulse generator is encapsulated in silicone rubber. The "subcutaneous extension" on the left, known affectionately to implanters as the "pigtail," contained three wires and was positioned just beneath the patient's skin. Connecting wire A to B via a small incision increased the pacemaker output; connecting B to C disabled the pacemaker. (Photo courtesy of Medtronic, Inc.)

retracted the ribs to expose a portion of the left ventricular surface. The surgeon drew the lead through a tunnel beneath the skin from the pacemaker pocket to the heart, sutured the two electrodes to the ventricular muscle, and plugged the lead into the pulse generator. Re-

placing a depleted pulse generator was simpler: the surgeon made a small abdominal incision under local anesthetic, detached the generator from the lead, and substituted a new one.43

43William M. Chardack, "Cardiac Pacemakers and Heart Block," in Surgery of the Chest, ed. John H. Gibbon, Jr., et al., 2d ed. (Philadelphia, 1969), pp. 824-65, gives details of surgical technique. By the mid-1960s it had become standard practice to employ a temporary transvenous endocardial lead (described below) to maintain the heart rate before and during surgery for implantation of a permanent myocardial pacemaker. Because of unexpectedly rapid battery depletion and occasional wire fail-


Noncompetitive Pacing for Intermittent Block

Until about 1965, permanent pacing of the heart had the character of an experimental technology, with journals often publishing ac- counts of unexpected crises such as broken wires and discussions of possible alternatives to mercuric oxide cells as the power source. Some practitioners also became concerned that asynchronous pacing might induce ventricular fibrillation in occasional patients who did not have fixed complete heart block but intermittent block with occasional normally conducted beats. In such cases the ventricles might receive natural and artificial signals in competition. A pacemaker impulse delivered at the end of ventricular contraction could trigger VF; the irritability of the heart muscle and hence the danger of VF appeared greatest when the pacemaker fired into tissue damaged by an earlier heart attack.44

Aware of the growing concern about pacemaker-induced VF, the biomedical engineer Barouh Berkovits, at American Optical Com- pany, designed a sensing capability into the pacemaker so that it would fire at a fixed rate, exactly as in an asynchronous pacer, but would reset itself if it sensed the depolarization of the ventricles.45

ures, some early patients had to endure a dozen or more implant procedures. Clearly, lead replacement entailed a much more severe procedure than replacement of the

pulse generator. The patient who had received Senning's implanted pacemaker in 1958, Arne Larsson, survived without pacing for more than a year after the failure of the initial device; he is still living and as of 1991 had had twenty-five pacemakers: letter from Larsson to author, June 25, 1991.

4Agustin Castellanos, Jr., et al., "Repetitive Firing Occurring during Synchronized Electrical Stimulation of the Heart," Journal of Thoracic and Cardiovascular Surgery 51

(1966): 334-40; Michael Bilitch et al., "Ventricular Fibrillation and Competitive Pac- ing," New England Journal of Medicine 276 (1967): 598-604; Leonard S. Dreifus et al., "The Advantages of Demand over Fixed-Rate Pacing," Diseases of the Chest 54 (1968): 86-89; William M. Chardack et al., "Pacing and Ventricular Fibrillation," Annals of the New York Academy of Sciences 167 (1969): 919-33. It had long been known that stimulating the ventricles during their "vulnerable phase" could induce fibrillation, but some leading figures in the pacing field remained skeptical about the possibility of pacemaker-induced VF because the pacemaker stimulus was so small and because direct evidence was lacking. It was difficult to demonstrate conclusively that pacemaker- induced VF had killed some patients unless their heart rhythms had been monitored at the moment of death. Interview with Barouh V. Berkovits, San Diego, California, May 7, 1993.

45 In the Berkovits pacemaker the ventricular electrode sensed the electrical indication of spontaneous ventricular activity (the R wave of the ECG tracing), and an ampli- fier magnified this signal. The amplified signal reset the timing circuit so that the pacer would not deliver another impulse until a preset interval, e.g., 850 milliseconds, had elapsed. In early pacemakers of this sort, the interval was immutable, but beginning in the 1970s it could be programmed by the physician. The Berkovits pacing mode was later renamed "ventricular inhibited" because a sensed ventricular pulse inhibited

602 Kirk Jeffrey

American Optical announced its new pacemaker (variously described as a "ventricular inhibited" or a "demand" pacemaker) in 1965 and within a few years had licensed other manufacturers to produce their own devices capable of pacing "on demand." By 1969, four-fifths of new pacemaker implants involved devices configured to avoid competition. Noncompetitive pacing had rapidly and completely superseded the asynchronous mode.46

The invention of noncompetitive pacing is a richly instructive episode. Confronted with hundreds of pacemaker-dependent patients, research cardiologists of the early 1960s had undertaken intense studies of heart block and other forms of slow heart rate. Once they began to follow patients on pacemakers over intervals of many months, it dawned on some that pacing had created a new cause of death, VF

resulting from pacemaker competition. The effort to account for these deaths led cardiologists to the insight that some cases of com-

plete heart block were not fixed but could revert to intermittent block with some normally conducted beats.47 Cardiologists had described the problem of pacemaker competition in print, but it was the engineer, Berkovits, who conceived of a way to solve it. He then invited

physicians' comments on the idea and their collaboration in clinical trials. Earlier choices in the design of implanted pacemakers, accumu- lated clinical experience with pacemaker-dependent patients, and in- tensified research into disturbances of heart rhythms all contributed to the medical framing of intermittent heart block and of the non-

competitive pacing mode.48

Partly in order to circumvent the Berkovits patent on ventricular

the pacer from firing. See George H. Myers and Victor Parsonnet, Engineering in the Heart and Blood Vessels (New York, 1969), pp. 34-49; and Bryan Parker, "Pacemaker Electronics," in Seymour Furman and Doris J. W. Escher, Principles and Techniques of Cardiac Pacing (New York, 1970), pp. 43-61.

46Louis Lemberg et al., "Pacemaking on Demand in AV Block," Journal of the Ameri- can Medical Association 191 (1965): 106-8. Medtronic introduced its first ventricular inhibited pacemaker in May 1967; a patent fight with American Optical ensued. The

acceptance of noncompetitive pacing by 1969 is reported in Victor Parsonnet, "The Status of Permanent Pacing of the Heart in the United States and Canada," Annales de cardiologie et d'angiologie 20 (1971): 287-91.

47 See the discussion in Dreifus et al. 48 One can carry the point further: the medical finding that legitimized noncompeti-

tive pacing depended for its authority on the prior acceptance of noncompetitive pacing. Only after noncompetitive pacing had come into widespread use did comparative mortality data provide firm corroborative evidence supporting the hypothesis that

patients on asynchronous pacers died more frequently than those on noncompetitive pacers. Before noncompetitive pacing, it had been more of a suspicion. See the Berko- vits interview (n. 44 above).


inhibited pacing, the Cordis Corporation introduced a "ventricular triggered" pacemaker. In this design, the device paced the ventricle at a fixed rate; but a sensed ventricular contraction, instead of inhib- iting the pacemaker, triggered it to fire instantaneously and then recycle. Delivered at a moment when myocardial cells had just depo- larized and were refractory to another stimulus, the pacemaker impulse did not compete with the heart's natural signal. The two systems, ventricular inhibited and triggered, were both widely used during the late 1960s, but Berkovits's inhibited mode eventually pre- vailed because it caused less drain on the pacemaker battery and because it seemed to emulate the "natural" escape mechanism of the heart in which certain cells below the site of the block, capable of spontaneously depolarizing but normally inhibited from doing so, will eventually fire in the absence of a normally conducted impulse.49

The Transvenous Route

From a medical point of view, the distinctive feature of pacing from 1960 on was its reliance on direct stimulation of myocardial tissue. In order for the surgeon to attach the pacing electrode to the heart, the patient had to undergo general anesthesia and surgical opening of the chest. Since most patients were elderly men and women suffering from severe heart disease, hospital mortality rates in the early and mid-1960s averaged about 7.5 percent.50

A group at Montefiore Hospital in the Bronx had already pio- neered a second route to the heart, this one through a vein and into the pumping chambers. In 1958, Seymour Furman, a first-year surgical resident at Montefiore, invented a catheter pacing lead, introduced it via the vein at the inside of the elbow, and passed it through

49J. Walter Keller, Jr., "Evolution of Pacemaker Systems," in Cardiac Pacing: Proceed-

ings of the IVth International Symposium on Cardiac Pacing, ed. HilbertJ. T. Thalen (Assen, 1973), pp. 123-27. On the heart's "latent pacemakers," see Zipes, "Specific Arrhyth- mias" (n. 18 above), pp. 685-86. Berkovits maintained that a biomedical engineer should always strive to "follow nature-if you can learn from it, you'd better do it."

Triggered pacing departed from "the normal way of the heart" (Berkovits interview [n. 44 above]). The belief that patients would be better off if treatment emulated "normal physiology" was fundamental to the appeal of ventricular inhibited pacing and later of dual-chamber pacing. Ironically, more "physiological" pacemakers also proved to be more complex. For a general discussion of the appeal of the physiological, see Joel D. Howell, "Cardiac Physiology and Clinical Medicine? Two Case Studies," in Physiology in the American Context, 1850-1940, ed. Gerald L. Geison (Bethesda, Md., 1987), pp. 279-92. See also Richard Sutton et al., "Physiological Cardiac Pacing," PACE 3 (1980): 207-19.

50Chardack, "Cardiac Pacemakers and Heart Block" (n. 43 above), p. 837, reporting on a study from 1967 that had reviewed many large series.

604 Kirk Jeffrey

FIG. 4.-Pincus Shapiro at Montefiore Hospital, fall 1958. The lower unit on the cart is an Electrodyne PM-65 pacemaker-defibrillator; resting atop it is an Electrodyne monitor with a small oscilloscope. The pacing lead enters a vein at the inside of the patient's left elbow. This apparatus plugged into a wall socket; the physician, Seymour Furman, later substituted a car battery and a converter. (Photo courtesy of Medtronic, Inc.)

the venous system and the right atrium and into the right ventricle of the patient's heart while observing its progress on a fluoroscope. Not knowing of the Medtronic portable pulse generator, Furman had connected the lead to an Electrodyne pulse generator that plugged into the AC electrical system (fig. 4). This apparatus paced Furman's second patient intermittently for ninety-six days and enabled the man to walk up and down the hospital corridor; eventually, pacing was discontinued, and the patient was able to leave the hospital and go


home.51 Over the next two years, Furman and his coworkers reported on dozens of additional cases of transvenous pacing.52

From the first, transvenous pacing could claim some significant advantages over the more invasive myocardial approach. Most important, the physician could gain access to a vein and introduce the catheter without subjecting the patient to major surgery. The technique also reduced the risk of damage to the heart tissue because the pacing electrode either floated free in the ventricle or barely touched the ventricular wall.

Yet the transvenous route did not gain widespread acceptance for long-term pacing in the United States until the late 1960s. Furman's youth and relative lack of renown may have been a factor initially; his removal from the scene for two years' military duty definitely slowed the development phase of transvenous pacing. There were early reports of intermittent failure to pace and of the catheter's perforating the vein. Some time elapsed before a standard technique emerged: those interested in transvenous pacing tried several veins before settling on one just beneath the collarbone as the most suitable for introduction of the catheter. More broadly, cardiac catheterization was a technique more familiar to cardiologists than to surgeons; indeed, use of the catheter as a diagnostic tool was perhaps the defin- ing ritual of cardiology. Because of the leadership of surgeons like Lillehei and Chardack, the medical world had grown accustomed to the idea of pacemaker implantation as a surgical procedure.53

Transvenous pacing spread rapidly after about 1965. The transvenous route first came into use during the early 1960s as a means of temporary pacing during surgery to implant a myocardial pacemaker; their experience with temporary transvenous pacing helped

51 This case, one of the most dramatic and influential in the history of pacing, was reported in Furman and Schwedel, "An Intracardiac Pacemaker" (n. 38 above). See also "Electrode in Heart Saves Man's Life," New York Times (November 27, 1958), p. 36.

52See, e.g., Seymour Furman et al., "The Use of an Intracardiac Pacemaker in the Control of Heart Block," Surgery 49 (1961): 98-108, and "Transvenous Pacing: A Seven-Year Review," American Heart Journal 71 (1966): 408-16; and Victor Parsonnet and Alan D. Bernstein, "Transvenous Pacing: A Seminal Transition from the Research Laboratory," Annals of Thoracic Surgery 48 (1989): 738-40.

53Seymour Furman et al., "Implanted Transvenous Pacemakers: Equipment, Tech- nic and Clinical Experience," Annals of Surgery 164 (1966): 465-74; Howell, "Changing Face of Twentieth-Century American Cardiology" (n. 8 above); Donald Baim and Richard J. Bing, "Cardiac Catheterization," in Cardiology: The Evolution of the Science and the Art, ed. Richard J. Bing (Chur, 1992), pp. 1-28.

606 Kirk Jeffrey

accustom surgeons to the techniques of catheterization.54 Reports from Europe of successful long-term transvenous pacing and the introduction of a flexible transvenous lead in 1965 (a variant on Char- dack's coiled-spring design) contributed to a shift toward the transvenous technique. Perhaps the clinching factor proved to be doctors'

growing realization that the transvenous procedure was less risky for their elderly patients. Hospital mortality rates from transvenous pacing were 0-3 percent.55 Indeed, Chardack himself began to use the transvenous route. By 1970, experienced implanters had switched in

large numbers to transvenous pacing, while new entrants to the field were accepting it as the normal path to the ventricle.56 Today virtually all pacing leads are introduced transvenously and stimulate the heart from within. The patient remains conscious throughout the procedure, now typically an hour or less in duration.57

Pacing in the 1960s: Treatment for Chronic Disease

Cardiac pacing spread rapidly in the 1960s, nicely exemplifying the "desperation-reaction" model of technological diffusion: when a disease is life-threatening and no existing therapy seems to help, doctors will adopt a promising new therapy-particularly when the results are quick, dramatic, and easy to interpret-even before the de-

velopment phase for the therapy has run its course.58 By the end of the decade, the number of primary (first-time) implant procedures

54William M. Chardack, "Heart Block Treated with an Implantable Pacemaker,"

Progress in Cardiovascular Diseases 6 (1964): 507-37, at 517; Editorial, "'Intravenous' Cardiac Pacemaking," Journal of the American Medical Association 184 (1963): 582-83; I. Richard Zucker et al., "Dipolar Electrode in Heart Block," Journal of the American Medical Association 184 (1963): 549-52.

55 Rodney Bluestone et al., "Long-Term Endocardial Pacing for Heart-Block," Lancet 2 (1965): 307-12; Hans Lagergren et al., "One Hundred Cases of Treatment for Adams-Stokes Syndrome with Permanent Intravenous Pacemaker," Journal of Thoracic and Cardiovascular Surgery 50 (1965): 710-14. On mortality rates, see Chardack, "Car- diac Pacemakers and Heart Block" (n. 43 above), p. 837.

56Parsonnet, "Status of Permanent Pacing" (n. 46 above), p. 289. Parsonnet's pacemaker team at Newark Beth Israel Medical Center in Newark, New Jersey, had gone from six permanent transvenous pacemakers out of thirty-one implants in 1964 to

twenty-four out of thirty in 1965. 57In the early 1970s, manufacturers introduced kits to assist the physician with

transvenous lead manipulation. The kit includes a stylus through which a temporary guide wire and then the lead itself are introduced to the vein and advanced into the heart. The procedure can be more time-consuming if leads are to be introduced to both atrium and ventricle. On the transvenous technique, see Sutton and Bourgeois (n. 5 above), pp. 177-234.

58Kenneth E. Warner, "A 'Desperation-Reaction' Model of Medical Diffusion," Health Services Research 10 (1975): 369-83; H. David Banta, "Embracing or Rejecting Innovations: Clinical Diffusion of Health Care Technology," in The Machine at the


was approaching twenty thousand per year in the United States, while

primary and replacement implants combined were nearing fifty thousand per year (table 1). Within this overall picture of rapid adoption, pacing underwent so many technological and procedural changes in the 1960s that even speaking of the decade as a single era may appear to strain logic. Yet all the innovations were introduced in furtherance of a clear, overriding goal: to create a prosthetic device that would

permanently manage a heart in complete block. To all appearances, both the pacemaker and the procedure for

implanting it had stabilized by 1970: the standard pacing device of that era was a fully implanted, ventricular inhibited pacemaker that stimulated the inner surface of the ventricle via a transvenous lead. In nearly all cases, this apparatus ministered to a patient whose symptoms included ventricular bradycardia, dissociation of the atria and ventricles, and dizziness or blackouts-the symptoms of heart block.

Despite the rapid acceptance of transvenous pacing, the typical im-

planter of the 1960s and early 1970s remained a surgeon and the central ritual in the field of cardiac pacing remained the act of im-

planting the pacemaker in a hospital operating room.59 The practice of pacing reflected the procedure-oriented character

of American medicine. Throughout the 1960s, surgeons and device manufacturers were the principal sponsors of pacing development. Since the standard implantation technique of the early 1960s entailed

exposure of the myocardial surface of the heart, pacing was dissemi- nated in tandem with heart surgery itself, proceeding generally from core institutions (large medical centers often affiliated with medical schools) to the periphery (doctors in private practice with privileges at general hospitals).60

Bedside, ed. Stanley Joel Reiser and Michael Anbar (New York, 1984), pp. 65-92; Thomas P. Hughes, "The Development Phase of Technological Change," Technology and Culture 17 (1976): 423-31. The implantable pacemaker appears to be a case in which innovation (the introduction of the technology into the marketplace and its diffusion into widespread use) proceeded simultaneously with development. This pattern would be highly unlikely in a new life-sustaining medical device today because the Food and Drug Administration, under the Medical Device Amendments of 1976 and the Safe Medical Devices Act of 1990, would refuse to license the device for

general use until extensive clinical trials had been conducted. 59Victor Parsonnet found that, in 1972, about seven implanters in ten were surgeons:

"A Survey of Cardiac Pacing in the United States and Canada," in Thalen, ed. (n. 49 above), pp. 41-48.

60Pacemaker manufacturers estimated in the early 1970s that between one-quarter and three-fifths of implanting physicians treated fewer than five new patients per year: Parsonnet, "Survey of Cardiac Pacing," p. 42. See also Parsonnet, "Status of Permanent

Pacing" (n. 46 above), p. 287; and Daniel M. Fox, Health Policies, Health Politics: The British and American Experience, 1911-1965 (Princeton, N.J., 1986), p. 210 and passim.

608 Kirk Jeffrey

Chardack of the V.A. Hospital in Buffalo was the pivotal medical figure in these years: Chardack's announcement of the first clinically effective implant in 1960, his invention of the coiled-spring electrode in 1962, and his meticulous analyses of his group's successes and failures galvanized others to try cardiac pacing. Chardack and his associate, engineer Wilson Greatbatch, worked closely with the manufacturing firm Medtronic in Minneapolis. For nearly a decade, all Medtronic pulse generators bore the "Chardack-Greatbatch" brand name. The team from Buffalo were "key consultants" to the firm, overseeing its implantable pacemaker program and keeping in touch with clinicians around the United States.6' But Medtronic was by no means the only firm to introduce a "permanent" pacemaker in the early 1960s. Sooner or later, each of the medical research teams that were actively at work on pacemaker development established a rela- tionship with a device manufacturer.62 Medtronic maintained its market dominance partly through its technological head start but also because of its preexisting reputation with medical equipment, its con- tacts with surgical groups, and its association with pioneers in cardiac pacing such as Lillehei, Bakken, Chardack, and Greatbatch.63 In the fast-developing pacing industry, the firm by mid-decade had assumed the role of industry leader even though its first pacemaker dated back only to 1958.

For a number of reasons, the barriers to entry remained quite low in the pacemaker industry throughout the 1960s. Federal require- ments for expensive and time-consuming controlled clinical trials to assess the safety and efficacy of life-sustaining medical devices did not come into existence until 1976. Though manufacturers secured patent protection for some devices and components, many of the key components of early pacemakers such as batteries, wires, and the biocompatible silicone-rubber encapsulation for a pulse generator were standard products purchased from other manufacturers; other components, notably the blocking-oscillator pacing circuit of the early implantables, were in the public domain. Newer entrants to the industry commonly sought market share by introducing elements of tech-

61Bakken interview (n. 32 above). 62 All of the early devices are described by their inventors in William W. L. Glenn, ed.,

"Cardiac Pacemakers," Annals of the New York Academy of Sciences 111 (1964): 813-1122. 63Creative Strategies, Inc., "Medical Electronics" (Palo Alto, Calif., 1973), copy at

Medtronic Library, Fridley, Minnesota; Jerry Flint, "Medtronic: Medicine, Electronics and Profit," New York Times (April 4, 1976), sec. 3, pp. 1, 9; Daniel R. Denison, Corporate Culture and Organizational Effectiveness (New York, 1990), pp. 95-108. The principal large corporation to introduce a line of pacemakers was General Electric, but its devices did not win widespread acceptance; GE withdrew from pacing in 1977.

TABLE 1 GROWTH OF CARDIAC PACING IN THE UNITED STATES

Population 65 Years Estimated Total Implants and Older Primary Implants per

Estimated Primary Implants (Replacements Included) (in Millions) Older Population* Year (1) (2) (3) (4)

1960-64 ................... 2,500 5,000 ....

1965 ......................... 2,900 5,700 18.2 1/7,845 1967 ......................... 8,250 15,000 18.8 1/2,848 1969 ......................... 16,000 27,000 19.5 1/1,523 1972 ......................... 25,000 45,000 19.9 1/995

1975 ......................... 57,000 90,000 22.7 1/498

1978 ......................... 69,000 100,000 24.1 1/437

1981 ......................... 118,000 142,000 26.3 1/278

SouRcEs.-My estimates for the pacemaker implant data (cols. 1 and 2) are based on data given in William M. Chardack et al., "Five Years' Clinical

Experience with an Implantable Pacemaker: An Appraisal," Surgery 58 (1965): 915-22, at 915; William Chardack, "Heart-Block Treated with an

Implantable Pacemaker: Past Experience and Current Developments," in Resuscitation and Cardiac Pacing, ed. Gavin Shaw, George Smith, and

Thomas J. Thomson (Philadelphia, 1965), pp. 213-49, at 246; Victor Parsonnet, "The Status of Permanent Pacing of the Heart in the United States

and Canada," Annales de cardiologie et d'angiologie 20 (1971): 287-91, at 288, and "A Survey of Cardiac Pacing in the United States and Canada," in

Cardiac Pacing: Proceedings of the IVth International Symposium on Cardiac Pacing, ed. HilbertJ. T. Thalen (Assen, 1973), pp. 41-48; B. S. Goldman and

Victor Parsonnet, "World Survey on Cardiac Pacing," PACE 2 (1979): W1-W17, at W3; Victor Parsonnet, Candice C. Crawford, and Alan D. Bernstein, "The 1981 United States Survey of Cardiac Pacing Practices,"Journal of the American College of Cardiology 3 (1984): 1321-32, at 1322-23; and industry estimates of pacemaker sales. Population data (col. 3) are from U.S. Bureau of the Census, Statistical Abstract of the United States (Washington, D.C., various years).

*Approximately 80 percent of pacemaker patients are age 65 and older. Thus, col. 4 = (col. 1 x 80%)/col. 3.

610 Kirk Jeffrey

nological novelty. American Optical's "demand" and Cordis's "triggered" pacemakers were outstanding examples.

The discovery and analysis of pacemaker competition and Berko- vits's invention of a pacing mode that could reliably sense and respond to cardiac activity pointed to emerging new relationships among laboratory research, doctors' clinical experience, and corporate research and development. It was clear, first, that the growing clinical use of pacing had encouraged a great deal of new research into the precise nature of various heart conduction disorders that

produced arrhythmias.64 As cardiologists gained new understanding of these disorders, advances in microcircuitry and other pacemaker components permitted manufacturers to introduce new pacing modes suitable for managing them.65 During the decade of the 1960s, the locus of inventive activity shifted away from the laboratories of

physician-inventors such as Zoll, Chardack, and Furman to the medical device firms.

The invention and spread of pacing in the 1950s and 1960s coincided with the postwar growth of prepaid hospital insurance. A re-

sponse to the growing use of expensive technology in hospitals, insurance tended to reduce cost constraints on doctors and hospitals by creating a situation in which none of the three direct parties to the medical transaction-care provider, patient, and hospital-had a

pressing interest in economizing. As Rosemary Stevens remarks,

64Pacing engendered a great deal of interest in the physiology of the conduction

system and the mechanisms of cardiac arrhythmias. For example, the number of arti- cles on the heart conduction system published in American medical journals and listed in Index Medicus rose tenfold between the years 1950-54 and 1963-67, from thirteen to 129. A similar increase occurred in publications on heart block and related topics. The pacemaker itself became a tool in the analysis of arrhythmias. The technology of His-bundle electrocardiography, first reported in 1969, entailed atrial pacing. Invasive

cardiologists employ catheter electrodes to record intracardiac electrical activity at various sites and may pace the atrium in the process; electrophysiologists overdrive the heart with a pacemaker to test its propensity to go into sustained tachycardia or VF. See

Benjamin J. Scherlag et al., "Catheter Technique for Recording His Bundle Activity in Man," Circulation 39 (1969): 13-18; Scherlag, "The Development of the His Bundle

Recording Technique," PACE 2 (1979): 230-33; Parsonnet and Bernstein, "Transve- nous Pacing" (n. 52 above); Douglas P. Zipes, "The Contribution of Artificial Pacemak-

ing to Understanding the Pathogenesis of Arrhythmias," American Journal of Cardiology 28 (1971): 211-22; William Grossman, "Cardiac Catheterization," in Braunwald, ed., Heart Disease (n. 18 above), pp. 180-203.

65Pacemaker circuitry is a large subject that I have chosen to avoid in this article. For brief introductions from the period examined here, see R. D. McDonald, "The

Design of an Implantable Cardiac Pacemaker," Medical and Biological Engineering 4

(1966): 137-52; Myers and Parsonnet (n. 45 above), pp. 181-91; and Parker (n. 45 above).


"hospital expenditures and reimbursement mechanisms drove each other, in an expansionary spiral." By 1960, about two-thirds of the American public enjoyed coverage under some type of private hospital insurance; but the remaining third, including the elderly, lacked insurance and often found that the cost of hospital care was outdis-

tancing their ability to pay out of their own pockets.66 In the aftermath of the Democratic landslide of November 1964,

a broad coalition of interest groups-organized labor, various indus- trial associations, Blue Cross and the private health insurance indus-

try, hospitals, and the American Association of Retired Persons (AARP)-was finally able to persuade Congress to create a federal

program that would cover most costs of hospitalization and doctors' fees for Americans over age sixty-five. The 89th Congress passed the Medicare Bill, and President Lyndon Johnson signed it into law on

July 30, 1965.67 Beginning on July 1 of the following year, the federal

government through the Medicare program began to pay costs associated with pacemaker implantation and follow-up in patients aged sixty-five and older, or about four-fifths of the pacemaker patient population.68 Medicare Part A (hospital insurance) paid for the pacemaker itself and for hospital services and procedures including workup and the primary or replacement implantation procedure. Medicare Part B covered 80 percent of physicians' fees, outpatient follow-up care, and subsequent office visits to check on the pacer's performance.

By guaranteeing payment of "reasonable and customary" charges, Medicare greatly reduced the cost of cardiac pacing for the elderly patient, provided no incentive for the hospital or the doctor to elect not to implant a pacer in marginal cases, and signaled that care pro- viders need not be greatly concerned about economizing in the choice of hardware.69 This is not to imply that cardiac pacing was a tremen-

dously costly treatment. Successive generations of hardware and the

66Stevens, In Sickness and in Wealth (n. 28 above), pp. 256-67, at 257. 67Judith M. Feder, Medicare: The Politics of Federal Hospital Insurance (Lexington,

Mass., 1977); Starr, Social Transformation (n. 28 above), pp. 363-78; Fox, Health Policies, Health Politics (n. 60 above), pp. 201-6.

68In the 1970s, the mean age of pacemaker patients at first implant was about sev-

enty-two: Seymour Furman, "Controversies in Cardiac Pacing," Cardiovascular Clinics 8 (1977): 313.

69Starr, Social Transformation (n. 28 above), pp. 374-78, 383-88; Stevens, In Sickness and in Wealth, pp. 281-83; Edward D. Berkowitz, America's Welfare State from Roosevelt to Reagan (Baltimore, 1991), pp. 166-80. Martin Feldstein, The Rising Cost of Hospital Care (Washington, D.C., 1971), was one of many observers to point out that private health insurance and Medicare contributed to increased demand for hospital services

by effectively reducing the cost to the average elderly person.

612 Kirk Jeffrey

advent of new implant techniques in fact substantially reduced the cost per patient between 1965 and 1975.70 But Medicare provided an immense encouragement for the further spread of cardiac pacing. Between 1967 and 1972, the number of first-time implants tripled (see table 1), and overall expenditures on cardiac pacing soared. One can reasonably conclude that policymakers and the public had in- tended this result since Medicare so clearly encouraged the acceptance and use of new medical devices and procedures.

Sick Sinus Syndrome and Dual-Chamber Pacing Cardiac pacing has repeatedly undergone rapid and radical trans-

formations; in the early 1970s, the assumptions and standard practices of just a few years earlier again came up for renegotiation as

cardiologists once again expanded the list of indications for pacing. As late as 1968, almost all pacemakers had been implanted to manage fixed or intermittent heart block.71 But beginning in that year, cardiologists framed a new conduction disease, the sick sinus syndrome (SSS). This term lumped together several disturbances of heart rhythm involving a default of the sinus node, the source of the electrical impulses that trigger atrial and then ventricular contraction-the heart's natural pacemaker. Within a few years, doctors were

implanting nearly as many pacers for SSS as for heart block.72 Sick sinus syndrome had a diverse list of symptoms. Doctors

learned that the condition might manifest itself as persistent and no- ticeable slowdown of the firing rate of the sinus node, an inadequate rate response to increases in the person's activity level, or sinus slowdown associated with an excessively rapid atrial rate. All these mal- functions could begin episodically but then later become fixed. In more severe forms, the impulse might fail to spread beyond the sinus node. Deprived of their normal signal from the sinus node, the atria

70Russell (n. 27 above), pp. 133, 156, and passim. 71At a pacing conference held in November 1968, virtually every paper assumed

that heart block was the sole indication for permanent pacing: Seymour Furman, ed., "Advances in Cardiac Pacemakers," Annals of the New York Academy of Sciences 167

(1969): 515-1075. 72J. Thomas Bigger, "Sick Sinus Syndrome Label for Many Cardiac Problems,"Jour-

nal of the American Medical Association 239 (1978): 597. M. Irene Ferrer, "The Sick Sinus

Syndrome in Atrial Disease," Journal of the American Medical Association 206 (1968): 645-46, offered the first formal definition of the condition with an extensive set of indications. For background on the diagnosis, see Louis J. Acierno, The History of Cardiology (London and New York, 1994), pp. 353-54. On the medical and social

framing of disease, see Charles E. Rosenberg, "Framing Disease: Illness, Society, and

History," in Framing Disease: Studies in Cultural History, ed. Charles E. Rosenberg and

Janet Golden (New Brunswick, N.J., 1992), pp. xiii-xxvi.


might fibrillate transiently or continuously; the ventricles might adopt a slow rate of contraction dissociated from the atria and eventually come to a halt.

As long as episodes of SSS remained intermittent, the patient typically experienced few or no symptoms. But as sinus failure grew more severe, patients suffered dizziness, fatigue, transient blackouts, kidney failure, congestive heart failure, and pulmonary edema. All of these resulted from the heart's inability to pump normally. Most of the symptoms, however, were not unique to SSS and could vary greatly from one patient to another. The same patient could manifest a range of symptoms from one office visit to the next, and some patients showed no clear symptoms at all except for slight irregulari- ties in the ECG tracing.73 Because of the erratic course of the "disease," diagnosing a failing sinus node could be difficult, especially in its early stages.

Some of these abnormalities had been described decades earlier, but the sinus node had come in for renewed attention in the early 1960s. The community of cardiac pacing specialists began to pay attention to the syndrome at the end of the decade, after they had resolved earlier uncertainties about pacing for heart block.74 They learned that sinus node disorders, though often difficult to diagnose, were not rare. There also seemed general agreement in the early 1970s that most such disorders did not present the same danger of sudden death as did complete heart block.75

From the time the term "sick sinus syndrome" appeared in print, cardiac pacing seemed the therapy of choice for its long-term management. Precisely because "the exact progress and timing of the

73M. Irene Ferrer, The Sick Sinus Syndrome (Mount Kisco, N.Y., 1974), pp. 91-93; David B. Shaw, "The Etiology of Sino-Atrial Disorder (Sick Sinus Syndrome)," American Heart Journal 92 (1976): 539-40; William J. Scarpa, "The Sick Sinus Syndrome," Ameri- can HeartJournal 92 (1976): 648-60; Henri E. Kulbertus, "Experience with Permanent

Pacing in the Sick Sinus Syndrome," Cardiovascular Clinics 14 (1983): 189-94; Zipes, "Specific Arrhythmias" (n. 18 above), p. 677.

74For a recent review of the literature, see Antonio Raviele and Francesco Di Pede, "Sick Sinus Syndrome: Modern Definition and Epidemiology," in Proceedings of the International Symposium on Progress in Clinical Pacing, ed. M. Santini et al. (Amsterdam, 1990), pp. 279-88.

75 On the difficulty of diagnosis, see Ferrer, "Sick Sinus Syndrome in Atrial Disease." The principal exception to the generalization that sinus node disorders did not present imminent danger to the patient was fixed sinus arrest, a condition that Ferrer considered the end stage in a progressive disease (Ferrer, Sick Sinus Syndrome, p. 117). As noted above, however, not everyone defined SSS as a single disease entity with a more or less predictable course. Later research identified several sequelae that could be quite serious: Kulbertus, p. 188.

614 Kirk Jeffrey

complications of [SSS] are still unknown in great detail," it seemed

prudent to "consider installing a pacemaker, for safety's sake, in the near future." According to the leading expert on sinus node disease, the clinician "need not wait" for symptoms "to be intolerable"; as soon as "symptoms of any note" appeared, "a pacemaker had best be installed." Indeed, she added, "periodic or sustained SB [sinus bradycardia] can no longer go unchallenged, even if asymptomatic."76 These statements opened the way for a rapid and substantial expansion of cardiac pacing by adding a large new class of arrhythmias to those already managed on pacemakers and by redefining the pacemaker as a prophylactic device, insurance against possible (but unpre- dictable) future deterioration in a patient's condition.77

Pacing for SSS came on with a rush in the early 1970s.78 By mid- decade, at least one-third and perhaps 40 percent of the primary pacemaker implantations in the United States were being carried out to manage the condition. This new indication for pacing coincided with a growth of about 125 percent in the number of new implants between 1972 and 1975.79 It is not difficult to account for the rapid

76 Ferrer, Sick Sinus Syndrome, pp. 97, 100, 107 (italics added). See also Michael Bilitch, "Sick Sinus Node Syndrome," in Modern Cardiac Pacing: A Clinical Overview, ed. Sey- mour Furman and Doris J. W. Escher (Bowie, Md., 1975), pp. 40-44; and Hilbert

J. T. Thalen, "Cardiac Pacing in Sick Sinus Syndrome," in To Pace or Not to Pace? Controversial Subjects in Cardiac Pacing, ed. Thalen and J. Warren Harthorne (The Hague, 1978), pp. 61-72.

77In another discussion Ferrer qualified this statement: if the sinus node was "slug- gish, but not dangerous, . . . for these patients it would not be fair to implant a

pacemaker." See M. Irene Ferrer, "Pacing and Sick Sinus Syndrome" (Part 2; interview) Medtronic News 6 (1976): 3-4, 4.

78 L. F. Silverman et al., "Surgical Treatment of an Inadequate Sinus Mechanism by Implantation of a Right Atrial Pacemaker Electrode,"Journal of Thoracic and Cardiovas- cular Surgery 55 (1967): 264-70, is an early case report of pacing for sinus node disor-

der; see also John W. Lister et al., "Electrical Stimulation of the Atria in Patients with an Intact Atrioventricular Conduction System," Annals of the New York Academy of Sci- ences 167 (1969): 785-806.

79In the first of his repeated surveys of cardiac pacing practice in the United States,

published late in 1971, Parsonnet did not inquire about SSS or about pacing modes other than asynchronous and ventricular inhibited. Two years later, Parsonnet re-

ported that fewer than half of the new pacemaker patients in the United States had

complete heart block, while more than half had presented with "sinus arrest" and other symptoms of SSS: Parsonnet, "Status of Permanent Pacing" (n. 46 above), p. 288, and "Survey of Cardiac Pacing" (n. 59 above), p. 43. Another cardiologist informally estimated that in 1976, 40 percent of new implantations were for sinus node problems: see Bigger (n. 72 above). Survey data from 1978-79 revealed that various forms of sinus node disease were the indications for 40.4 percent of new implants in the United States, while various forms of heart block accounted for 49.3 percent: B. S. Goldman and Victor Parsonnet, "World Survey on Cardiac Pacing," PACE 2 (1979): W1-W17, at W7.


diffusion of pacing for sinus node disorders: the standard pacemaker of that era, the ventricular inhibited pacer, at first seemed well suited for SSS as well as heart block. Doctors could simply carry out more

procedures of the sort they already knew how to do. However, just as concerns had developed about asynchronous pac-

ing in the mid-1960s, questions soon began to arise about the suit-

ability of ventricular inhibited pacing for sinus node disorders. The ventricular inhibited mode protected the patient from ventricular standstill and from pacemaker-induced VF, but it by no means re- stored full cardiac function. The choice of this pacing mode implied that the physician was giving up on the patient's sinus node and atria and would simply strive to maintain a ventricular beat.80 But

physiological studies indicated that atrial contractions, when properly synchronized with ventricular, augmented the heart's output of blood

by about 20 percent for people recovering from heart surgery or a heart attack. Properly synchronizing the beats of atria and ventricles also permitted the heart to respond more efficiently to heightened body activity level. Loss of normal synchrony could produce a variety of negative effects.8'

Sinus node dysfunction thus called for some form of atrial pacing to compensate for the failure of the sinus node. This implied a pacemaker with leads in both chambers. In 1971 such a device came on the market, the AV sequential or "bifocal" pacemaker. Atrioventricu-

80Arthur B. Simon and Allan E. Zloto, "Symptomatic Sinus Node Disease: Natural

History after Permanent Ventricular Pacing," PACE 2 (1979): 305-14, at 306. Ferrer, Sick Sinus Syndrome (n. 73 above), p. 97, recommended "demand" pacing, i.e., ventricular inhibited pacing. Parsonnet, "Survey of Cardiac Pacing," pp. 43, 45, showed that in 1973 when over half of the primary implants were for conditions other than com-

plete heart block, nearly nine-tenths of the pacemakers were ventricular inhibited devices.

81 Seymour Furman, "Therapeutic Uses of Atrial Pacing," American Heart Journal 73

(1973): 835-40; Sutton et al. (n. 49 above); Seymour Furman and Jay Gross, "Dual- Chamber Pacing and Pacemakers," Current Problems in Cardiology 15 (1990): 117-79. The chief adverse effect of pacing with a standard ventricular inhibited pacemaker that investigators had identified by the early 1970s was the "pacemaker syndrome" in which the ventricular pulse triggered by a pacemaker signal is conducted in a retro-

grade direction back to the atria. As a result of retrograde conduction, a common feature of sinus node dysfunction, the atria contract against closed atrioventricular valves; this forces blood backward from the atria into the pulmonary veins on the left side of the heart and into the systemic veins on the right side. Symptoms can range from lethargy and breathlessness to severe drop in blood pressure to syncope. As Kalman Ausubel and Furman noted, "The pacemaker syndrome represents a clinical

spectrum of intolerance to ventricular pacing": Kalman Ausubel and Seymour Fur- man, "The Pacemaker Syndrome," Annals of Internal Medicine 103 (1985): 420-29, at 425; see also Sutton and Bourgeois (n. 5 above), pp. 126-31.

616 Kirk Jeffrey lar sequential pacing built on ventricular inhibited pacing: a sensing- pacing electrode was placed in the right ventricle as before, but the implanting physician also introduced a pacing electrode into the right atrium. The pacemaker shifted automatically between three different modes as appropriate. In the presence of slow or absent atrial rhythm plus heart block, the pacemaker could deliver a stimulus to the atrium and then, after an appropriate interval, to the ventricle (true AV sequential pacing). If slow atrial rhythm was accompanied by adequate conduction from atria to ventricles, the pacemaker could pace the atrium alone. In the presence of both adequate atrial rhythm and conduction from atria to ventricles, it would be inhibited from stimulating at all. In effect, the pacemaker served as a prosthetic conduction system.82

Despite the claim that AV sequential pacing was more "physiological," the new pacing mode did not follow the same pattern of rapid physician acceptance as had occurred with ventricular inhibited pacing in the mid- and late 1960s. For the next decade, doctors who performed pacemaker implants resisted all dual-chamber pacemakers, in part because introducing two transvenous leads was a difficult procedure and positioning the atrial lead so that it would consistently pace the atrium sometimes proved time-consuming and frustrating.83 The actual functioning of dual-chamber pacers was more difficult to comprehend-the physician had to have a thorough understanding of pacemaker timing cycles-and the devices could produce complex ECGs.84 The complexity of this device may, indeed, have exceeded the technological and electrophysiological comfort level of many doctors who were implanting pacemakers in the early 1970s. Since it was

82Jack M. Matloff et al., "Experience with Implanted Bifocal, Sequential Demand Pacing," suppl. 3, Circulation 42 (1970): 182 (abstract); Cesar A. Castillo et al., "Bifocal Demand Pacing," Chest 59 (1971): 360-64. "Bifocal pacing" was the proprietary term

adopted by American Optical Company for AV sequential pacing. The company sold units at a variety of preset atrial and ventricular pacing rates and AV intervals. Today the dedicated AV sequential pacemaker is obsolete since successor dual-chamber devices can be programmed to sense and/or pace in either or both chambers. An earlier dual-chamber pacemaker, the Cordis Atricor, had held a small share of the market in the 1960s.

83For skeptical discussions of AV sequential pacers, see Seymour Furman et al., "Atrioventricular Sequential Pacing and Pacemakers," Chest 63 (1973): 783-89; Tha- len, "Cardiac Pacing in Sick Sinus Syndrome" (n. 76 above); Sutton et al., "Physiological Cardiac Pacing" (n. 49 above), p. 210.

84See, e.g., Sutton and Bourgeois (n. 5 above); Furman et al., A Practice of Cardiac Pacing (n. 7 above); Furman and Gross, "Dual-Chamber Pacing"; S. Serge Barold et al., "Characterization of Pacemaker Arrhythmias Due to Normally Functioning AV Demand (DVI) Pulse Generators," PACE 3 (1980): 712-23.


widely believed that SSS patients did not face a high immediate risk of sudden cardiac death (in contrast to patients in complete heart block, who did face that risk), there apparently seemed little reason to implant a dual-chamber pacemaker; doctors stuck with ventricular inhibited pacing for SSS.85 Thus, in 1978-79, when about 40 percent of all implants ministered to sinus node dysfunction, 85 percent of all newly implanted pacemakers were ventricular inhibited, and only about 6.5 percent were dual-chambered devices.86

A Field for Cardiologists? As the pacemaker evolved from a tool in the doctor's intensive-care

armamentarium to a permanent prosthesis for chronic disease, many of the roles and rituals of pacing-the elderly patient with ominous symptoms, the ECG workup, the implant procedure in a special room filled with high-tech equipment and masked professionals-super- ficially continued to resemble those of acute-care medicine. In effect, implantation of a pacemaker enabled the doctor to treat a chronic degenerative disease such as heart block or sinus node disorder as if it were an acute illness. If all went well, the patient walked out of the hospital "cured," while the doctor received compensation for performing a procedure. But beneath the veneer of acute-care medicine, pacing by the mid-1970s entailed complexities and physician respon- sibilities undreamed of just a few years earlier.

It was already clear by the 1970s that "almost any physician with reasonable dexterity can learn to implant a pacemaker"; but to earn recognition as a fully competent specialist, the physician also had to be conversant with the rapidly growing body of knowledge about arrhythmias, the ever-changing hardware of pacing, pacemaker pro- gramming, the management of postimplant complications, and patient follow-up over the long term. Surgeons or mixed teams of surgeons and cardiologists continued to implant most pacemakers; but

85Barouh Berkovits, the designer of the AV sequential inhibited pacemaker, com- mented later that "benefits of sequential pacing are less dramatic" than the benefits of ventricular inhibited pacing for complete heart block, where "there is a life and death issue to be considered": Barouh Berkovits, "A Modern Pioneer's Perspective" (interview), Medtronic News 9 (1979): 9-11, at 10. However, later research indicated that ventricular inhibited pacing for SSS does not significantly reduce patient mortality while dual-chamber pacing does make a considerable difference. See Raviele and Di Pede (n. 74 above), p. 284, citing many studies.

86Goldman and Parsonnet (n. 79 above), pp. W7, W9. Only 2 percent of the pacers implanted were AV synchronous, while 4.5 percent paced in other modes capable of

stimulating the atrium. This survey probably has sampling problems, as the authors concede; but there seems no reason to doubt that the great majority of patients diagnosed with SSS were receiving ventricular inhibited pacemakers in the late 1970s.

618 Kirk Jeffrey

the medical transaction included many new activities both before and after implant, and here the training of the cardiologist came into play.87

Because of the accumulation of knowledge about arrhythmias of the heart, the clinician of the 1970s had available a wide range of possible diagnoses. Various subcategories of heart block had been defined, each presenting subtly different manifestations in the ECG and each inviting somewhat different treatment by means of pacemakers. Disorders of the sinus node could be equally complex. A growing number of papers in the field focused on the analysis of difficult ECGs. With the advent of new techniques for recording electrical activity at sites within the heart itself, the physician was presented with even more tracings to analyze. It was cardiologists, not surgeons, who possessed the training and experience for this kind of work.88

The hardware of cardiac pacing was also changing in ways that tended to recast pacing as a close relative of cardiology. The newer pacemakers presented the doctor with a vast array of decisions: the market offered dozens of models by the mid-1970s, many of them programmable from outside the patient's body by means of devices that communicated with the implanted pulse generator through coded elec- tromagnetic pulses. The doctor could noninvasively and repeatedly change pacing rate, pulse duration and amplitude, sensitivity of the electrodes to spontaneous electrical activity within the heart, and other parameters. Millions of different combinations were theoretically available, although most were inappropriate for practical use.89

After 1970, the rising number of patients, increased pacemaker (and patient) longevity, and the growing complexity of pacemakers led many hospitals to open outpatient pacemaker clinics that maintained contact with paced patients in the months and years after implant. By taking regular ECGs, technicians under physician supervi- sion could decide how to reprogram the pacer as the patient's disease

87The quoted phrase appears in Parsonnet, "Cardiac Pacing as a Subspecialty" (n. 7

above), p. 991. See also J. Warren Harthorne et al., "Who Should Implant a Pacemaker

System, Surgeon or Cardiologist?" in Thalen and Harthorne, eds. (n. 76 above), pp. 263-70.

88Samuel Bellet, Clinical Disorders of the Heart Beat, 3d ed. (Philadelphia, 1971), is a

representative text of that period. On His-bundle recording, see Scherlag et al. (n. 64

above). 89David C. McGregor et al., "The Utility of the Programmable Pacemaker," PACE

1 (1978): 254-59. To the chagrin of leading figures in the field of pacing, as late as the mid-1980s a substantial proportion of programmable pacemakers, perhaps two- fifths, were implanted with their default settings and never reprogrammed: Victor Parsonnet et al., "Cardiac Pacing Practices in the United States in 1985," American

Journal of Cardiology 62 (1988): 71-77, at 73.


progressed, judge when battery depletion called for replacement of the pulse generator, and spot other problems such as failure of the lead. For patients not able to visit the clinic, it was possible to transmit a simple ECG indicating the pacemaker impulse rate by telephone; this was enough to forewarn of battery failure. By the mid-1970s, most physicians who were "frequent implanters" at large medical centers had established pacemaker clinics located in or near their hospitals. For doctors who lacked any connection to a hospital-based pacemaker follow-up clinic, several private companies cropped up in the

early 1970s to handle pacemaker monitoring and record keeping.90 Transvenous pacing, the growing complexity of ECGs and pacing

equipment, the longer survival of patients, and the obvious need for

long-term follow-up all contributed to a gradual de facto redefinition of pacing as a distinct field but one with strong affinities to cardiology. Surgeons did not bow out overnight and continue to implant many pacemakers; but board certification in surgery no longer seemed, in itself, an appropriate credential for a practice of cardiac pacing. By the 1980s half of the implanters in the United States, and a higher proportion of newer entrants to the field of pacing, were cardiologists.9'

Like the field of cardiac pacing, cardiology "took off" as a subspecialty after about 1970. It had required twenty-eight years (from 1942 through 1969) for the American Board of Internal Medicine to certify the first one thousand cardiologists. The next thousand took only five years, and after 1975 more than one thousand physicians gained certification each year. Many of the younger cardiologists moved into invasive cardiology, an informal hospital-based subfield centered on ad-

90In the mid-1970s, about one-half to three-fifths of pacemaker patients survived for at least five years after implantation: Furman, "Controversies" (n. 68 above), pp. 313-14. On follow-up, see Furman et al., "The Pacemaker Follow-Up Clinic," Progress in Cardiovascular Diseases 14 (1972): 515-30; Seymour Furman, "Transtelephone Ob- servation of Implanted Cardiac Pacemakers," Medical Instrumentation 7 (1973): 196- 202; Michael Bilitch et al., "Physician Follow-Up of Patients with Permanent Cardiac Pacemakers," in Thalen, ed., Cardiac Pacing (n. 49 above), pp. 443-48; and Victor Parsonnet and George H. Myers, "Organization of a Cardiac Pacing Service," in Cardiac Pacing: A Concise Guide to Clinical Practice, ed. Philip Varriale and Emil A. Naclerio (Philadelphia, 1979), pp. 13-27. As of 1973, about half of the pacemaker centers in the United States were estimated to have created some sort of organized pacemaker surveillance system: Parsonnet and Manhardt (n. 3 above), p. 254.

91 Victor Parsonnet, "Pacing in Perspective: Concepts and Controversies," Circulation 73 (1986): 1087-93, at 1092, and "Cardiac Pacing as a Subspecialty" (n. 7 above). Since 1983, the payment reforms imposed by Medicare have tended to advantage cardiologists over surgeons as implanters of pacemakers: Stamato et al., "Permanent Pacemaker Implantation" (n. 4 above); T. Bruce Ferguson,Jr., et al., "Should Surgeons Still Be Implanting Pacemakers?" Annals of Thoracic Surgery 57 (1994): 588-97.

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vanced technologies and such procedures as balloon angioplasty and cardiac pacing and more recently on new procedures such as ablation therapy and coronary atherectomy. These invasive procedures employ the cardiologist's traditional procedure, catheterization.92

The subspecialty of cardiology and the field of cardiac pacing fed on each other. Through their technical studies of arrhythmias and their

pioneering use of heart catheterization, cardiologists had helped lay the groundwork for the framing of new diseases of the heart's electrical system and for pacing's redefinition as a technology for long-term man-

agement of chronic diseases. On their own turf, the analysis and man-

agement of heart arrhythmias, they tended to manifest great optimism about the benefits of pacing. They were highly receptive to the idea of

treating slowdowns of the heartbeat such as complete fixed heart block, intermittent heart block, and the sick sinus syndrome by giving the patient an implanted pacemaker; and once pacing had gained acceptance in treating one type of arrhythmia, they were strongly inclined to ex-

plore its utility in other situations.93

92 On the redefinitions of cardiology in recent decades and the field's association with invasive technologies, see Howell, "Changing Face of Twentieth-Century American Cardiology" (n. 8 above); Braunwald (n. 29 above); Parsonnet and Bernstein, "Transve- nous Pacing" (n. 52 above); and Richard S. Stack, Editorial: "New Interventional Tech- nologies in Cardiology," Mayo Clinic Proceedings 64 (1989): 867-70.

93For further discussion of this pattern, see H. David Banta et al., Toward Rational Technology in Medicine (New York, 1981), pp. 53-55, 58-72, 77-80; McKinlay (n. 2 above); Ichiro Kawachi and Nicholas Wilson, "The Evolution of Antihypertensive Therapy," Social Science and Medicine 31 (1990): 1239-43. Not surprisingly, the Ameri- can practice of paying physicians for performing procedures has encouraged the growth of specialties such as invasive cardiology that are centered on procedures. Howell, "Diagnostic Technologies" (n. 9 above), shows that "regular" American physicians were able to raise their own professional status and differentiate themselves from sectarians in the early 20th century by associating themselves firmly with science and

technology. In contrast, cardiologists were sometimes cool to new pacing hardware that would entail drastic changes in their management of patients. They rapidly accepted ventricular inhibited pacing, transtelephone monitoring, and the lithium battery, but were more cautious about dual-chamber and multiprogrammable pacemakers. In such cases one senses very strongly the latent tension between the "leaders" in cardiac pacing, who perform many implants and speak up for new technology, and the thousands of more technologically conservative physicians who perform only a few implants per year. Useful discussions of the diffusion of new medical technologies that intensely discuss the role of physicians include Banta (n. 58 above); Eugene D. Robin, Matters

of Life and Death: Risks vs. Benefits of Medical Care (New York, 1984); Joseph D. Bronzino et al., Medical Technology and Society: An Interdisciplinary Perspective (Cambridge, Mass., 1990); and Stuart S. Blume, Insight and Industry: On the Dynamics of Technological Change in Medicine (Cambridge, Mass., 1992), esp. pp. 5-21. Most scholars working on the

subject have been influenced by Stanley Joel Reiser, Medicine and the Reign of Technology (Cambridge and New York, 1978).


Conclusion

From its beginnings after World War II through the mid-1970s, the cardiac pacemaker might have served as an emblem of the clinical successes and the rapid redefinitions of postwar American medicine. In pacing, as in medicine generally, unmanaged growth stood out as a particularly striking characteristic. In the absence of a national registry, authoritative statistical data on pacemaker implantations for the era before 1975 do not exist; but scattered information permits an estimate of the burgeoning number of procedures. It appears that from the very early 1960s through the mid-1970s, the number of

implants (counting primary and replacement procedures) doubled

every two to three years. Growth probably slowed for a few years in the late 1970s because the number of replacements declined as a

longer-lived kind of pulse generator, powered by lithium batteries, came into use. After about 1978, the rate of growth in pacing picked up again and remained robust until Medicare payment reforms went into effect in 1983. Federal support for the consumption of health- care products and services by the elderly, advances in doctors' own

pacing know-how based on an accumulation of clinical cases, and

ongoing research into heart arrhythmias encouraged in part by the success of pacing itself all contributed to this growth in pacing between 1952 and 1975.

Like heart surgery and cardiology, pacing was optimally positioned to flourish in an era of optimism about medical technology as the means to "conquer" refractory diseases. Federal reimbursement and

regulatory policies played a powerful enabling role in the expansion of pacing: until 1976, the Food and Drug Administration lacked au-

thority to regulate the introduction of new medical devices, and Medi- care imposed no serious oversight on reimbursement for pacemaker implantations before 1983.94

Lest the point be overlooked, we should also note that pacing was

94Stevens, In Sickness and in Wealth (n. 28 above), pp. 322-27. Before 1983, Medicare

paid doctors and hospitals the "usual and customary" charge for a given procedure. Under this system, incentives to economize were weak. In 1983, amendments to the Social Security Act changed Medicare to a prospective reimbursement system. Phased in over the next three years, the new rules grouped all hospital treatments into 467

Diagnosis-Related Groups (DRGs), each of which was assigned a fixed rate of reimbursement regardless of the length of the patient's stay in the hospital or the resources used. The DRG system established a price ceiling for each reimbursable procedure and thereby pressured hospitals to economize. If the hospital could treat the patient for less than the fixed amount, it came out ahead. In 1985, the DRG system was extended to physician services. Of the original 467 DRGs, four involved pacemaking, two covering initial implants and two covering replacement or revision of a pacemaker.

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clinically effective: it kept patients alive in complete heart block whose prognosis without pacing would have been extremely poor, and beginning in the mid-1960s it enabled many of them to enjoy moderately active lives. To this extent, Zoll is correct: "It really worked." But technological triumphalism seems out of touch with the needs of the 1990s. Even while conceding that cardiac pacing has saved thousands of men and women from sudden cardiac death or from a poor quality of life in old age, that the pacemaker is a wonder of engineering, and that the per-patient cost of pacing is modest compared to some other medical procedures, observers have still been troubled by the growth dynamic of the field.95

As concern built up in the 1970s and 1980s about the high cost of health care in the United States, many critics singled out advanced medical technologies as a principal cause of the financial crisis in American health care. Cardiac pacing came under direct attack in 1982 when the Public Citizen Health Research Group, an organization under the Ralph Nader umbrella, announced that over one-third of the permanent pacemaker implantations performed in Maryland hospitals in 1979 and 1980 had been "unnecessary" or "questionable."96 A blue- ribbon committee appointed by the Maryland Society of Cardiology reviewed the medical records of pacemaker patients but concluded that only a few of the implants had truly been "unnecessary."97

The controversy-one of several that erupted over cardiac pacing in the early 1980s-suggested that more than twenty years into the history of pacing for chronic bradycardia, high-tech medicine was as likely to evoke uneasiness as celebration; perhaps the controversy also indicated that the heroic image of the heart specialist had eroded. The Nader group, however, had an incomplete understanding of the dynamics of growth in cardiac pacing. It was certainly true that the practice of paying doctors for performing procedures gave them fi-

95 Interview with Paul M. Zoll, Boston, February 5, 1990; Rosenqvist and Nordlander (n. 17 above). Electrostimulation of the heart, however, has probably played a rather small part in the overall decline in mortality rates from heart disease; see Lee Goldman and E. Francis Cook, "The Decline in Ischemic Heart Disease Mortality Rates," Annals of Internal Medicine 101 (1984): 825-36. For statements by troubled physicians, see Victor Parsonnet, "The Proliferation of Cardiac Pacing: Medical, Technical, and Socio- economic Dilemmas," Circulation 65 (1982): 841-45; John A. Kastor, "Pacemaker Ma- nia," New England Journal of Medicine 318 (1988): 182-83. For comparative implant rates by country in the 1970s, see Goldman and Parsonnet (n. 79 above), pp. W3-W4.

96 Health Research Group, Permanent Pacemakers in Maryland (Washington, D.C., July 1982).

97Leonard Scherlis and Donald H. Dembo, "Problems in Health Data Analysis: The Maryland Permanent Pacemaker Experience in 1979 and 1980," American Journal of Cardiology 51 (1983): 131-36.


nancial incentives to go ahead with implants in borderline cases. Yet to claim that many implants were obviously "unnecessary" was to miss an important point. Observers outside the field took it for granted that some stable, authoritative set of implantation criteria must exist, but the medical definition of necessity had never remained fixed for

long.98 The field had changed repeatedly, and with each change physicians' list of indications for pacing had grown longer. This expan- sionist tendency had been visible even before the creation of the Medicare program in the mid-1960s. By 1972, many patients were

receiving pacemakers for arrhythmias that were not immediately life

threatening yet seriously compromised their capacity to live even

moderately active lives. In that sense, perhaps one could say that the

implants were "unnecessary." But one could claim equally well that a redefinition of "necessity," indeed of what good health means for an

elderly person, was under way in American society, prompted in part by the success of cardiac pacing and other treatments of chronic de-

generative conditions of old age. In medicine as in other social realms, the purely technical proper-

ties of a new device or procedure do not determine how the innovation will be deployed. The hardware of pacing and the standard tech-

niques of applying the pacemaker changed fundamentally between 1952 and 1975. But even more significantly, the customs and habits of doctors changed. In the early years, doctors generally understood

pacing as an emergency or short-term treatment applied in the hospital to patients in acute distress. Later they reconceived pacing as a

way to manage chronic heart block "permanently." Still later they defined new diseases of the heart that were suitable for pacing; they also redefined their practice to include active management of the

pacemaker long after the day of implantation. In the process, physicians and hospitals created entire new organizations called pacemaker follow-up clinics that were staffed by technicians and maintained elab- orate computer databases on hundreds, perhaps thousands, of pa-

98Formal criteria for implantation were introduced in 1984 but have been revised and expanded: Robert L. Frye et al., "Guidelines for Permanent Cardiac Pacemaker

Implantation," Journal of the American College of Cardiology 4 (1984): 434-42, a report of a joint task force of the American College of Cardiology and the American Heart Association. Compare Joel D. Howell's observation that the practice of cardiology- indeed the very meaning of the term cardiology-has undergone repeated redefinition. "The structure and content of cardiology" do not enjoy a stable reality separate from the goals of physicians, the struggle of organizations, and broader developments in medical thought. Cardiology "is historically mediated and constantly changing" (Howell, "Changing Face of Twentieth-Century American Cardiology" [n. 8 above], p. 780).

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tients. All this would have been unimaginable in 1952 or even 1965. Doctors who were reluctant to go along with this new role as active

managers of patients' hearts would eventually get out of the field, leaving it in the hands of those who were more comfortable with the

repeated reinvention of cardiac pacing.

Teo Te Wei - Pacing the Heart

Health & Medicine

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