Management of a pacemaker recall

Volume 74,

Number 5

November 1977

THORACIC AND CARDIOVASCULAR SURGERY The Journal of

Management of a pacemaker recall Rapid technological changes in the medical devices industry have led to an alarming deterioration in the reliability and safety of the cardiac pacemaker. During the past 4 years. we have been subjected to eight pacemaker recalls involving 469 pulse generators (3/.9 percent of our total of 1,470 implants). Upon notification of a pacemaker recall, it becomes the implanting physician's responsibility to verify the manufacturer's list of affected units and to make a frank disclosure in person to the patient and/or responsible relatives. Appropriate communications also must be established with government agencies. the news media. malpractice insurance carriers. and local hospital boards. Although a pacemaker manufacturer may initiate a recall and make recommendations as to whether or not an individual pulse generator should be replaced prophylactically or subjected to increased surveillance, these decisions rest primarily with the implanting physician. To date. 138 (29.4 percent) of our recall pacemakers have been replaced because of unpredicted failure, premature rate drop, or fear of catastrophic failure at a mean time of /0.6 months. Of the 46 (9.9 percent) units that have been replaced for other reasons. only 27 thus far have demonstrated a rate drop with normal battery depletion. Patient deaths have accounted for 69 (/4.7 percent) units and /6 (3.4 percent) units have been lost to follow-up. The remaining 200 (42.6 percent) recall pacemakers are under increased surveillance by our pacemaker center. Transtelephone monitoring assumes a major role in the management of the pacemaker recall, not only to predict but also to identify the failure of any individual unit. Schedules should be adapted to the expected performance of suspect units and should be revised as circumstances dictate. We wish to emphasize the need for improved pacemaker standards and for more extensive testing of new pacemaker models prior to release for implantation in human beings.

David C. MacGregor, M.D., Edward J. Noble, M.D. (by invitation), John D. Morrow, M.D. (by invitation), Hugh E. Scully, M.D. (by invitation), H. Dominic Covvey, M.Sc. (by invitation), and Bernard S. Goldman, M.D., Toronto. Ontario, Canada

From the Pacemaker Evaluation Center, Toronto General Hospital, Toronto, Ontario, Canada. Supported in part by the Ontario Heart Foundation and the Marion Webster Taylor Fund. Read at the Fifty-seventh Annual Meeting of the American Association for Thoracic Surgery, Toronto, Ontario, April 18, 19, and 20, 1977. Address for reprints: David C. MacGregor, M.D., Director, Cardiovascular Laboratories, Room 68, Banting Institute, 100 College St., Toronto, Ontario, Canada M5G lL5.

In

1974, the Inter-Society Commission for Heart Disease Resources reported that, in general, pacemaker manufacturers have lived up to their implied responsibilities with high quality products and that, although there have been manufacturer recalls, their rarity is a measure of the over-all excellence of most pacemakers.' Since early 1972, however, the United States Food and Drug Administration (FDA) has issued bulletins on between 35,000 and 40,000 implanted

657

658

The Journal of Thoracic and Cardiovascular Surgery

MacGregor et al.

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Fig. 1. The yearly number of new implants and replacements performed at the Toronto General Hospital from 1963 to 1976 inclusive. Although there was an initial drop in the number of replacements in 1973 (after the introduction of telephone monitoring). of particular note is the greater than threefold increase in the number of replacements from 1973 to 1975. in contrast to only a slight rise in the number of new implants. pacemakers that have come under suspicion because of specific indentified problems.> What went wrong and how have these patients fared? This report describes our own experience during the past 4 years with eight pacemaker recalls involving 469 pulse generators (31.9 percent of our total of 1,470 implants). As a result of this experience, we have developed a set of guidelines for the management of a pacemaker recall.

Patients in the study The Toronto General Hospital Pacemaker Clinic was established in 1970, and on Sept. I, 1972, a Pacemaker Evaluation Center was created to function as the computer-based focal point for regional doctors' offices as well as a peripheral network of clinics in small community hospitals. 3 In addition, transtelephone pacemaker monitoring was introduced not only to predict but also to identify the failure of any individual unit. This measure maximizes pacer longevity and patient security. During the following year there was a gratifying 9 percent drop in the percentage of pulse generator replacements to total implants (45.5 to 36.5 percent) and a 2 month increase in over-all mean pacer longevity (from 20.9 to 22.8 months)." We received our first notification of a pacemaker recall in July, 1973, involving 47 Cordis pacemakers

implanted since Sept. I, 1972. During the 4 year period ending Aug. 31, 1976, we were to be subjected to a total of eight pacemaker recalls involving 469 pulse generators (31 .9 percent of our total of 1,470 new implants and replacements). The percentage of pulse generator replacements to total implants rose sharply to a peak of 61. 7 percent in 1975, with mean pacer longevity falling to a low of 20.1 months. Fig. I is a bar chart which shows the yearly number of new pacemaker implants and replacements from 1963 to 1976 inclusive. Of particular note is the greater than threefold increase in the number of replacements from 1973 to 1975, in contrast to only a slight rise in the number of new implants. For the purposes of this discussion, the reasons for pulse generator replacement have been divided into three broad categories: (I) elective decision-the unit is functioning normally but replacement is carried out because of patient/doctor anxiety, manufacturer's recommendation, travel, competition (asynchronous units), or infection/erosion; (2) predicted failure-the unit demonstrates a rate change (increase or decrease) and is replaced before a loss of sensing and/or pacing occurs; and (3) unpredicted failure-the unit has failed to sense and/or pace before replacement can be carried out; this mayor may not be accompanied by a rate change.

Volume74 Number5 November, 19n

Pacemaker recall

659

Table I Recall No. (date)

Reasons

No. ofunits involved

No. of units in this study

Cordis

Faulty transistors cause malfunctions

13,350

47

II

Cordis

4,288

160

II

Cordis

237 4,900

10

II

Medtronic

Moisture saturates pacer epoxy; causes swelling Defective resistors Nonresealed hybrid microcircuits cause battery depletion Premature failure due to battery depletion

2,377

13

II

500

2

II

AHSC's Edwards Pacemaker Systems Arco Medical

Slight rate drift

II

Cordis

Malfunction of electronic circuitry

1,222

233

II

Medtronic

Metal migration

9,562

3

Class

T-154/157-5

Recalled by

(7/73)

T-163-5 (12/16/74) (8/7/75) T-119/122-5 (2/24/75) T-045/048-6 (12/18/75) T-117/118-6 (5/21/76) Not applicable (5/25/76) T-IlI/I12-6 (5/28/76) T-138/139-6 (8/2/76)

Corrosion of output pin

Totals

Table I summarizes the details of the eight pacemaker recalls which have affected our patient population during the past 4 years. 5. 6 Of the total of 36,442 units involved, 469 (1.3 percent) are included in this study. In July, 1973, we were notified by the Cordis Corporation that an estimated 13,350 pulse generators may show a change in rate or a loss of sensing and/ or pacing resulting from a transistor failure (Recall No. T-154/ 157-5). They recommended close surveillance of the affected patients during the first year of implant, when most failures were found to occur, and indicated that an increase of 2 beats per minute was an indication for immediate replacement. We elected to follow our 47 affected patients by weekly transtelephone assessments for the total duration of implant period in compliance with the manufacturer's recommendations. There were six elective replacements, 16 predicted failures, and II unpredicted failures of which three were related to lead problems. The remaining 14 patients either died or were lost to follow-up. The mean longevity of all explanted pulse generators in this group was a respectable 25.1 months. Our second Cordis recall came in the form of a letter dated Dec. 16, 1974 (Recall No. T-163-5). They described a gradual lowering of rate of some units in their routine in-house life-testing program as well as in some implanted units returned from the field. The problem was traced to an anomaly in the performance of a resistor in the rate circuit and involved an estimated 4,288 units (later extended by an additional 237 units). They

6

36,442

469 (1.3%)

stressed that the phenomenon was not accompanied by premature battery depletion, that capture and pulse regularity should be unaffected, and that there should be no adverse effect on the patient other than that which might be caused by a gradual lowering of rate. Monthly monitoring for 5 months after implantation was recommended to identify affected units (any rate decline greater than 3 beats per minute). We adopted a monthly monitoring schedule for all of our 160 affected patients for the total duration of implantation because several units demonstrated this failure mode after the initial 6 month period .. Table II indicates how these patients have fared as of Aug. 31, 1976. One hundred and one units (63.1 percent) have been replaced thus far, at a mean time of only 11.1 months and a mean rate of 62.9 beats per minute. Thirteen units still are under surveillance, at a mean time of 25.9 months and a mean rate of 67.9 beats per minute. Twenty-eight patients have died (presumably of unrelated causes), 13 units were replaced for other reasons, and five patients have been lost to follow-up. On Feb. 24, 1975, the Cordis Corporation notified us by letter that we had 10 of 4,900 implanted Omnicor pulse generators which could develop either a premature rate decrease followed by cessation of pacing, or else loss of sensing resulting in fixed-rate pacing (Recall No. T-119/122-5). Apparently there was a vendor fabrication problem that allowed moisture to be sealed into some of the hermetic hybrid packages which caused the malfunctions. Monthly monitoring through 14 months after implantation was recommended and

The Journal of Thoracic and Cardiovascular Surgery

660 MacGregor et al.

Table II. Cordis advisory (Stanicor Models 14317, L7, M7) No.

Replaced: Mean longevity Mean rate

11.1 mo. 62.9 b.p.m.

Under surveillance Mean time Mean rate

25.9 mo. 67.9 b.p.m.

101

13

Died (unrelated causes) Not applicable Lost to follow-up

28 13 5

Total

160

Table III. Current status of all recall units

______1 Removal related to recall Removal for other reasons Died Lost to follow-up Still under surveillance Totals

No.

138

46

1-%29.4 9.9 14.7 3.4

69 16 200

42.6

469

100

we complied with this recommendation. To date, four of the units have been replaced electively at a mean of 30.2 months, and three have been predicted failures associated with a rate change at a mean of 21.9 months. There was one unpredicted failure at 34.2 months, one patient has died, and one patient still is under surveillance. We received notification of our first recall from Medtronic, Inc., by a letter dated Dec. 18, 1975 (Recall No. T-0451048-6). This recall involved 2,377 pulse generators which might be susceptible to a sudden loss of output (over a period of a few days or less) as a consequence of electrical leakage paths external to the hermetically sealed circuit package. Of 51 Xytron pulse generators placed in life-test tanks, five time-dependent failures from the fifteenth month on were reported. Two clinical failures at 8 and 11 months, respectively, also had been confirmed. Medtronic recommended close follow-up for patients who had normal cardiac function most of the time and prophylactic replacement at 15 months for those patients who required artifical cardiac pacemaker support at all times. Because we already had seen one premature battery depletion at only 13.1 months in our group of 13 affected patients, we elected to replace eight units prophylactically in patients who showed some degree of pacer dependency (mean, 11.7 months). One unit

was not replaced by choice, and the remaining three patients had died prior to notification of the recall. On June 14, 1976, Medtronic notified us that this potential complication had not materialized and recommended that special monitoring of these 2,377 Xytron pulse generators from the advisory group cease. Recall No. T-117/118-6 from Edwards Pacemaker Systems came in a letter dated May 21, 1976. We were notified that we had two of a possible 500 pacemakers that might be subject to a sudden loss of output zero to 12 months after implantation due to output pin corrosion. We were asked to consider prophylactic replacement in pacer-dependent patients up to 12 months after implantation, but as both of our patients were approaching this time, we elected to follow them by weekly transtelephone assessments. On May 25, 1976, we received a telegram from Arco Medical asking us to monitor one of our units for a slight rate drift. Although notification was sent out regarding six such patients, it was not officially designated as a recall. Patient anxiety and physician uncertainty as to the actual risk involved led us to replace this unit prophylactically. Cordis announced a recall of 1,222 of its Kappa pulse generators on May 28, 1976, and we were notified both by letter and by a personal visit (Recall No. T-Il III 12-6). In this case, the problem was identified as a corrosion of the weld, allowing body fluid to penetrate the hermetically sealed metal enclosures which could cause malfunction of the electronics, infection, or irritation. Two clinical failures had occurred at 12 and 15 months, respectively, and two of 263 units in saline test tanks had failed at 14 and 18 months, respectively. Monthly monitoring and consideration of prophylactic replacement at 10 months for pacerdependent patients was recommended. As the major validator of this pacemaker (233 units) and because we had not identified any such failures in our own patient population, we elected to adopt the policy of weekly transtelephone assessment for all our patients. As of Aug. 31, 1976, there have been five elective replacements, one predicted failure, and 13 unpredicted failures of which seven were related to lead problems. In addition, 26 patients have died, six have been lost to follow-up, and 182 remain under increased surveillance. In consultation with the manufacturer, we revised our monitoring schedule to once monthly beginning in November, 1976. Our most recent recall came from Medtronic and referred to a sudden loss of output of Xytron pulse generators resulting from a phenomenon called "metal migration" (metallic bridging of an electrical compo-

Volume 74 Number 5 November. 1977

Pacemaker recall

66 I

Anxiety 8.4

Loss of Sensing Travel 4.2

and Pacing 10.9

Competition 0.8 Infection/Erosion 5.7 Rate Increase 2.2

Fig. 2. A percentage analysis of our 4 years' experience with 780 pulse-generator replacements (recall units included). Twenty-eight percentof the units wereremoved electively, predictedfailures accounted for 47 percent of replacements, and unpredicted failures accounted for the remaining 25 percent of replacements. nent) due to water vapor permeating the metallic circuitry enclosure (Recall No. T-138/139-6). This recall involved 9,562 units and their letter of Aug. 2, 1976, indicated that the incidence rate rose from about 0.1 percent per month during the first 6 months to about 1.0 percent per month at about 10 months. It recommended a modified follow-up schedule or replacement if the patient's condition represented a sufficiently high physiological risk. We elected to replace two of our three affected units, and one patient remains under increased surveillance despite our recommendation for prophylactic replacement. Table III summarizes the current status of all recall units as of Aug. 31, 1976. One hundred and thirtyeight (29.4 percent) of our recall pacemakers have been replaced because of unpredicted failure (34 units), premature rate drop (93 units), or fear of a catastrophic failure (11 units), at a mean time of 10.6 months. Of the 46 (9.9 percent) units that have been replaced for other reasons, only 27 thus far have demonstrated a rate drop with normal battery depletion. Patient deaths have accounted for 69 (14.7 percent) units and 16 (3.4 percent) units have been lost to follow-up. The remaining 200 units (42.6 percent) are under increased surveillance by our pacemaker center. For purposes of comparison, Fig. 2 provides an analysis of our total experience with 780 pulse generator replacements during the same 4 year period (recall units included). Sixty different pacemaker models from eight manufacturers are included in this analysis. Elective replacement accounted for about 28 percent of our replacements and the mean longevity of these units was 25.1 months. Predicted failures accounted for about 47 percent of replacements (mean

Table IV. Morbidity associated with unpredicted failures (1973, 1974, 1975, 1976)

Asymptomatic Symptomatic only Symptomatic requiring temporary lead* Known deaths Totals

No.

%

145 35 II

76

191

100

18

6

o

o

• 1.4 percent of all replacements.

Table V. Guidelines for management I. 2. 3. 4. 5. 6. 7. 8.

Notification of FDA by manufacturer Classification of recall Notification of physician Verification of recall list Decision on management Notification of patient and/or relatives Notification of outside physician(s) Communications with government agencies, news media, malpractice insurance carriers, and local hospital boards 9. Provision of adequate follow-up facilities 10. Modification of recall protocol as necessary II. Return of pacemaker to manufacturer 12. Corroboration of failure mode

longevity, 22.7 months), and unpredicted failures accounted for about ~ percent of replacements (mean longevity, 16.4 months). It is worthwhile to note that these figures are remarkably similar to those in a recent multicenter study of 387 removed pulse generators reported by Bilitch and his associates. 7 The over-all mean longevity period for all 780 units was a disappointing 21.8 months. If the removed recall units whose mean longevity was only 13.7 months are excluded, the per-

662

MacGregor et al.

formance of the nonrecall units becomes a more acceptible 24.3 months. If one examines the performance of the 432 units that reached 18 months and were replaced on the basis of transtelephone monitoring, the mean longevity rises even further to 29.1 months. In essence, these figures represent the performance of the mercury-zinc oxide battery as only 10 of the 780 replaced pulse generators (1.3 percent) contained alternative power sources. The patients at greatest risk in this study are those who have experienced an unpredicted pulse-generator failure (that is a failure of sensing and/or pacing before replacement can be carried out). Table IV is a 4 year analysis of our total of 191 unpredicted failures, which represents 25 percent of our total of 780 replacements. Over three quarters (76 percent) of these patients were totally asymptomatic, 18 percent had mild-to-moderate symptoms, and only 6 percent (1.4 percent of all replacements) had sufficient symptoms to warrant the emergency placement of a temporary pacing lead. Although it usually is impossible to determine pacemaker failure as a cause of death, we had no deaths between the time the pulse generator failure was identified and its replacement. Lead fractures were associated with only 2.1 percent of all replacements and other lead problems ("exit block," dislodgement, penetration, and perforation) were associated with only 3.0 percent of all replacements. Guidelines for management The various steps in the management of a pacemaker recall are summarized in Table V. Since the Medical Device Amendments of 1976 to the Federal Food, Drug, and Cosmetic Act were signed into law on March 28, 1976, the FDA's regulatory powers have been expanded and clarified and the relationship between manufacturers and the FDA has been better defined. 8 As soon as a product problem has been identified, it is the manufacturer's responsibility to notify the FDA immediately. The agency's Health Hazards Evaluation Committee then classifies the recall, as outlined in Table VI. After classification a recall is listed in the weekly FDA Enforcement Report. In addition, the manufacturer may elect to issue a press release to coincide with the notification of the FDA. The next step in the recall procedure is for the manufacturer to specify how the physician will be contacted, what action will be requested, and how the manufacturer will verify that physicians have been notified. 9 When the implanting physician receives notification of a pacemaker recall (by telephone call, telegram, reg-

The Journalof Thoracic and Cardiovascular Surgery

istered letter, and/or personal visit), it becomes his responsibility to verify the manufacturer's list of affected units and to make every effort to contact the patients involved. At the present time, pacemaker registries (often computer-assisted) are mainly the realm of the manufacturer and are based on information provided by the implanting physician. All too often, patient registration forms are filled out inaccurately, incompletely, or not at all by inexperienced nurses or paramedical personnel. How, then, can the manufacturer provide accurate and complete information to the implanting physician? It becomes imperative that pacemaker teams provide complete information to manufacturers as well as develop an accurate means of data collection and retrieval for themselves. Most important would appear to be the need for a national pacemaker registry to ensure the collection of vital statistics on pacemaker patients across the country. 3. 7, 10 Although a pacemaker manufacturer may initiate a recall and make recommendations as to whether or not an individual pulse generator should be replaced prophylactically or subjected to increased surveillance, these decisions rest primarily with the implanting physician. Frequently this can be accomplished by consultation with other physicians who have had more experience with the pacemaker in question and with its performance. Historically, most pacemaker recalls have not required surgical removal of the unit but have required careful monitoring of the patient by a physician.f In our experience we have elected to replace prophylactically only 11 of 469 recall pacemakers (2.4 percent) but, in retrospect, nine of these patients probably should have been monitored carefully instead. We also have shown that, despite the fact that unpredieted failures occur with alarming frequency (25 percent), the morbidity associated with these failures is low, provided that they are identified early by frequent monitoring (Table IV). The relative importance of the degree of pacer dependency in any individual patient is difficult to establish. It can be argued that almost all pacemaker patients become pacer dependent at some time or another, otherwise they would not have a pacemaker in the first place. Patients who have demonstrated total pacer dependency (for example, at the time of pulse generator replacement) probably should be handled more cautiously than those who consistently have demonstrated a satisfactory underlying rhythm. When does a failure rate (expressed in percentage per month) become unacceptable? In general, the highest acceptable random component failure rate is about 0.15 percent per month, and, indeed, most current pacemaker models perform considerably better than

Volume74 Number5 November. 19n

this. When the failure rate becomes 1.0 percent per month (as in the recent Medtronic Xytron Recall No. T-138/139-6), prophylactic replacement should be considered seriously, at least in those patients who have been shown to be totally pacer dependent. The mode of pulse generator failure also should be examined before reaching a decision regarding patient management. Providing the incidence is not too high, a gradual rate change or a failure of sensing and/or pacing usually can be managed by increased surveillance. Fortunately, all of the recall failure modes in this study fell into this category. However, if the failure mode actively poses a threat to the patient's well-being (for example, explosion, runaway, double pulsing), immediate prophylactic replacement should be considered. As soon as a course of action has been decided upon, the physician should arrange a personal visit with the patient and/or responsible relatives in order to make a direct and frank disclosure of the problem and to indicate how it will be managed. This extra effort will go a long way toward allaying a patient's fear and anxiety and usually will assure his/her total cooperation. This interview should be documented carefully in the patient's records and a copy should be sent to any other physicians who are responsible for the patient's care. Appropriate communications also should be established with government agencies, the news media, malpractice insurance carriers, and local hospital boards, all of whom share, in some way, the responsibility for the physician's actions." Once the physician has accepted the responsibility for management of these patients, he/she must ensure that the appropriate facilities are available for increased surveillance. Small numbers of patients can be handled by frequent office visits; however, if the number is large, or if the patients do not live locally, the physician may require the services of a regional pacemaker clinic that can provide transtelephone monitoring up to once or twice per week if necessary." 11 In our experience, most pacemaker manufacturers are willing to provide or assist in the acquisition of the necessary transtelephone monitoring equipment on request. Alternatively, a commercial follow-up service can be employed to supplement, but not replace, the physician's own follow-up program. Schedules should be adapted to the performance of suspect units and should be revised as circumstances dictate. In an effort to improve patient care, the FDA conducts "effectiveness checks" by contacting some of the physicians and/or hospital administrators involved. In addition, the manufacturer reports to the FDA on the progress of the recall. Sometimes it is possible to ter-

Pacemaker recall

663

Table VI. Classification of recalls

~I II

III

Description

Violative product poses reasonable probability of serious adverse health consequences or death Violative product may cause temporary or medically reversible adverse health consequences; probability of serious consequences remote Violative product not likely to cause adverse health consequences

minate a recall, as in the case of the Medtronic Xytron Recall No. T-045/048-6, or to modify the surveillance schedule, as in the case of the Cordis Kappa Recall No. T-II 1/112-6. Finally, if and when a recall pacemaker is removed, it is essential that it be returned promptly to the manufacturer along with comments regarding patient symptomatology, the mode of failure, and observations made at the time of explanation. Likewise, it is the responsibility of the manufacturer to provide information to the physician following analysis of the explanted unit. If a pacemaker fails within the time guaranteed by the manufacturer, the patient or the insurer will receive a refund from the same company if the unit is returned. A method should be developed for the return of all pacemakers to the manufacturer, even if removed after the warranty period. Only in this way will manufacturers and physicians acquire satisfactory information on failure modes. 1 In this study, 169 of the removed recall pacemakers (92 percent) were returned to the manufacturer for analysis, and there was a positive correlation with our clinical diagnosis of pacer failure in 156 instances (92 percent corroboration). Discussion Although the FDA uses the term "recall" to describe all product corrective actions, most manufacturers feel that the term, as it applies to cardiac pacemakers, instills unnecessary fear and anxiety in the patients involved." 12 Thus, when the manufacturer notifies the physician of a recall, such action often is carried out under the guise of such terms as "performance update," "patient advisory," or "physician notification," all of which must be translated into a recall class, as defined in Table VI, before deciding upon a course of action. The media also can serve a valuable function in keeping the public informed, and it is the responsibility of the medical profession, industry, and government agencies to provide factual and relevant data to the press. Likewise, a responsible press should avoid unnecessary sensationalism, such as that practiced by the Miami Herald when it published the head-

664 MacGregor et at.

line "Pacemakers Cause of 26 Deaths." 13 As pointed out in a subsequent editorial by James R. Jude, the psychological trauma of such information from a respected paper does far more harm to our older citizens who wear a pacemaker than any defects in the pacemaker have ever done. The legal aspects of cardiac pacing recently have been discussed in detail by Segall. 14 When a pacemaker malfunction results from the implantation of a defective unit, the manufacturer and hospital may be enjoined with the implanting physician as defendants in a malpractice suit. If the implanting physician has performed the procedure in accordance with acceptable standards of medical treatment, in selection, testing, and implantation, he usually will be relieved of liability on the grounds that he would have no reasonable way of determining that the unit was defective prior to placement within the patient and that he had to rely upon the manufacturer's warranty of a reliable product. Recovery for pacemaker failure may be obtained on the basis of negligence of a defendant manufacturer in departure from standards of due care, with respect to design, manufacture, assembly, packaging, inspection for defects, or testing of the instrument for proper function. Segall points out, however, that courtroom proof of this contention, as a practical matter, is usually quite difficult to obtain. The hospital also may be liable for damages if it can be shown to be a vendor or agent of the vendor and, therefore, liable under a breach of warranty theory and/or if it is demonstrated as being negligent for having supplied defective equipment per se or for failure to inspect for discoverable defects. Why has there been such a proliferation of pacemaker recalls during the past 4 years? Has the demand for too much new high technology posed problems which could not have been foreseen by pacemaker design engineers? One of the recurrent problems in the area of manufacturing has been early unwarranted optimism regarding the longevity of power sources and the durability of components. As pulse generator design increases in versatility and complexity, problems of malfunction continue to occur. 1 Has the race to bring new products to market before the recently enacted Medical Device Amendments of 1976 jeopardized the quality control and pre market testing standards of manufacturers? In 1976, a multicenter study estimated that, during the previous 2 years, in excess of 70 different pacemaker models were available from more than 15 companies." These figures appear to be quite conservative in view of the fact that we alone have removed no less than 60 different pacemaker models from only eight manufacturers during the past 4 years.

The Journalof Thoracic and Cardiovascular Surgery

In addition, three of our eight recall notices contained data based on units placed in life-test tanks which confirmed specific identified problems at various times ranging up to 18 months. Surely increased premarket testing of new pacemaker models, either in experimental animals or in a simulated biological environment for a minimum of 18 months, would provide a safer and more reliable product for pacemaker patients. There is also room for improvement in the basic design and choice of components for cardiac pacemakers. A persistent cause of pacemaker failure has been the leakage of body fluids into the pacemaker with short circuiting of the various components. 15 Tyers and Brownlee." point out that the past reluctance of the pacemaker industry to hermetically seal devices was related to battery outgasing problems and possibly to inadequate welding technology. Now that these problems largely have been solved, they even go so far as to suggest that a continuation of the development and sales of nonhermetic pacemakers beyond a reasonable brief phase-out period should be considered to be malpractice on the part of the device manufacturers. The reliability requirements of components to be used in pacemakers are more severe than all but the most stringent military and space requirements." Despite the fact that adequate stocks of high-reliability parts are not always available, pacemaker manufacturers should demand that reluctant vendors add production lines for class A parts with failure rates of one in a billion, at least 10 times the mean time between failures of class B parts. 17 Manufacturers must recognize that the ultimate objective for reliability of components is to have failures reduced to an absolute minimum. At present cardiac pacemakers are becoming the second biggest category in the medical equipment industry (after x-ray equipment). It is estimated that, by 1984, the pacemaker market probably will exceed 900,000 implants annually, even taking into consideration that the annual growth rate probably will be reduced from about 30 percent to about,20 percent, due to the impact of long-life pacemakers.P Pacemaker recalls will continue to occur, but we hope that their incidence will decrease sharply as a result of the past 4 years' experience. We are not proud of the fact that over 30 percent of our pacemaker implants have been subject to recall, but we hope our experience has provided a set of guidelines for the physician who is called upon to manage a pacemaker recall. We wish to thank the staff of the Toronto General Hospital Pacemaker Evaluation Center and our cardiovascular research assistant, Susan D. Smardon, for their assistance in the collection of data for this study.

Volume 74 Number5 November, 1977

REFERENCES

2 3

4

5

6

7

8

9 10

II

12 13 14 15

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Parsonnet, V., Furman, S., and Smyth, N. P. D.: Implantable Cardiac Pacemakers: Status Report and Resource Guideline, Am. 1. Cardiol. 34: 487, 1974. Jurgen, R. K.: Learning From (Heart) Failure, IEEE Spectrum 13: 71, 1976. Goldman, B. S., Noble, E. J., MacGregor, D. c., Morrow, J. D., Covvey , H. D., Heller, J. G., and Taylor, K. W.: Conceptual Development of a University Pacemaker Centre, in Thalen, H. 1. T., editor: Cardiac Pacing, Proceedings of the Fourth International Symposium on Cardiac Pacing, Groningen, The Netherlands, April 17-19, 1973, Assen, The Netherlands, 1973, Van Gorcum, pp. 465-470. Goldman, B. S., Heller, J. G., Noble, E. J., Covvey, H. D., MacGregor, D. C., and Morrow, 1. D.: Critical Analysis of Pulse Generator Replacement, Ann. Thorac. Surg. 18: 156, 1974. Recalls of Medical Devices and Diagnostic Products, (Suppl.) Devices and Diagnostics Letter 2, No. 46, Nov. 14, 1975. Recalls of Medical Devices and Diagnostic Products, (Suppl.) Devices and Diagnostics Letter 3, No. 44, Oct. 29, 1976. Bilitch, M., Escher, D., Furman, S., and Parsonnet, V.: Twelve Month Experience With Commercially Available Cardiac Pacemakers-A Multicenter Study, Am. J. Cardiol. 37: 121, 1976. U. S. Congress. Senate and House. An Act to Amend the Federal Food, Drug, and Cosmetic Act to Provide for the Safety and Effectiveness of Medical Devices Intended for Human Use, and for Other Purposes, Public Law 94-295, 94th Congress, 2d Session, 1976. The Medical Device Recall. .. A Semantics Problem Too, Medtronic News 6: 10, 1976. Goldman, B. S., Noble, E. J., Heller, J. G., and Covvey, H. D.: The Pacemaker Challenge, Can. Med. Assoc. J. 110: 28, 1974. Furman, S., and Escher, D. J. W.: Transtelephone Pacemaker Monitoring: Five Years Later, Ann. Thorac. Surg. 20: 326, 1975. Pacer's Makers Drag Feet on "Recalls," Med. World News 16: 21,1975. Pacemakers Cause of 26 Deaths, Miami Herald, April 9, 1975. Sagall, E. L.: Legal Aspects of Cardiac Pacemakers, Conn. Med. 39: 325, 1975. Parsonnet, V.: Innovations in Implantable Pacemakers, in Silverman, H. T., and Miller, I. F., editors: Electrochemical Bioscience and Bioengineering, Princeton, N. J., 1973, Electrochemical Society, Inc., pp. 96-123. Tyers, G. F. 0., and Brownlee, R. R.: The Nonhermetically Sealed Pacemaker Myth, or, Navy-Ribicoff 22,000-FDA- Weinberger 0, J. THORAC. CARDIOVASe. SURG. 71: 253, 1976. High-Reliability Parts for Pacemakers in Short Supply, Electronics 48: 39, 1975.

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18 Cywinski, J. K.: Advances in Cardiac Pacemakers-New Power Sources and Circuit Technology, in IEEE Intercon. Conf. Record, New York, 1975, Session 2: Electronic Instrum. in Med., New York, 1975, IEEE, pp. 2/41-2/44.

Discussion DR. DRYDEN P. MORSE Moorestown, N. J.

I agree that "recall" is a bad term. Some really are "recalls"; more are better called "pacemaker alerts." "Pacemaker dependent" is really too loose a term. Everyone who has a pacemaker is at least "minimally" dependent on the pacemaker. A pacemaker-dependent person is one who can't get out of bed without a pacemaker and an "absolutely dependent" patient is one who has no heartbeat without the pacemaker. This is very important in discussing the so-called "recalls" which are better termed "alerts." Alerts spring from experienced pacer failures. There are two modes of failure with different clinical implications for the patient: In one type the pacer fails suddenly, as in some cases with sudden zero output owing to shorting from metal migration; in the other type the pacer slows up over a period of weeks, albeit prematurely. These latter cases can be adequately and safely detected by routine monitoring of the pacer over the telephone with appropriate action (nonemergency replacement) when the slowing is detected. Patients suspect of the first, or sudden and complete type of pacemaker failure, should have "overdrive" in the heart station or electrocardiogram laboratory to determine the degree of pacemaker dependency. Patients who are absolutely dependent, of course, should have the pacemaker replaced if the expected type of possible failure is sudden and complete stoppage. We recently treated such a patient who, on overdrive at a rate of 85 beats per minute, showed no spontaneous rhythm. The pacer alert in her case resulted in replacement of the still-functioning pacer. Overdrive is accomplished with two small electrodes on a single handle which is put on the chest in a very temporary manner. An auditory pulse monitor is previously put on the finger so that if the patient has no beat at all, a sudden silence ensues and the overdrive unit is quickly removed from the chest. This is a dangerous technique. No more than 4 to 5 seconds of asystole is acceptable. The patient is liable to a stroke and/or a heart attack or death. Testing patients for dependency by overdriving should be done in recall series wherein the expected mode of pacemaker failure is sudden and complete and the underlying rhythm of the patient is not known. DR. CHARLES P. BAILEY New York, N. Y.

Some of you may know that I am also a lawyer of rather recent vintage, and I actually have a small legal practice limited to doctors-some with malpractice connotation and

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some with government agency problems. Since the law of Canada and the law of the United States differ significantly, I thought it might be well for me to point this out to you before you become somewhat misled. I present you with the Greek goddess of justice with the scales. She was originally blindfolded. This photograph was taken from the U. S. Supreme Court Building-I guess the justices didn't want anyone to charge them with dispensing blind justice, so they took the blindfold off. But that is not the way the law operates in the English speaking countries. Our law and Canadian law both derive from the time of William the Conqueror, who in 1066 conquered England and became the absolute ruler of that land. In order to resolve the disputes and conflicts which were bound to arise between members of his nobility-newly created from his army-he devised what was called "trial by battle." The disputing knights were put on horses, wearing metal suits, and were given a spear each. The priests would bless the event and would proclaim: ''The Lord will strengthen the arm of him who should prevail." This was a very good arrangement for William, because he would need the support of both of them when the Saxons predictably would rise up against him in the future. Even the fellow who got speared off the horse would get the idea that he must somehow have been in the wrong because the strength of the arm of that other fellow must have been supernaturally enhanced or he could have disposed of him easily. In any event, he would not blame William for ruling against him. Unfortunately, with the passage of time, some of these fellows got older or feebler, or they could not get up on a horse because they were too fat, as did William, himself. However, if such a knight had a valiant son, it was permissible for him to "carry the colors" of his father and represent him in this early civil lawsuit. If his "boys were all girls," perhaps the noble had a valiant son-in-law. It soon became similarly acceptable for the son-in-law to represent his interests. Some of even the greatest did not have any children. However, they all had private armies with knights in their employ, some of whom were good at unhorsing other knights. In time, it became accepted that one of these fellows could ride and "carry the colors" of the liege lord and be his "champion" at the "trial." This represented a real advance in the quality of legal representation in those days. When their enlistments ran out, usually in 7 years, these superior jousters became free agents, "frei-lancers." Now, they could hire out to whomever would pay. These were the first lawyers-in the English speaking part of the world. It is really the same today. However, in the United States you deal with a jury, whereas in Canada you usually deal with a judge (except in capital or criminal cases). Present law is not clear as to what the physician's responsibility is when he gets notice of a recall of some implantable instrument or an alert as to its possible breakdown. When he does not know what the law is going to be eventually, it is not wise to look for it in the statutes. The question to ask is, "What will the jurors say?"

I. "There was a relationship of physician and patient here. " 2. Some departure from a proper standard of care was the cause of an injury. 3. But, if there is no injury, of course, there is no redress to be obtained. No.2 is the important one: Did you depart from some duty which you owed the patient? Did you do what was reasonable under the circumstances? This is the way you will be judged by a jury of your' 'peers. " Please remember that and behave accordingly. DR. W. GERALD RAINER Denver. Colo.

This paper is an exceptionally acute analysis of some of the problems involved with pacemaker recall. In hopes of putting this into a different perspective, I have collected data on advisories or "alerts" since 1975. The FDA has issued 25 advisories concerning pacemaker products. Approximately 39,000 pulse generators and 1,552 leads and external generators, produced by 13 different manufacturers, were involved. The affected units were among approximately 250,000 units sold in the United States. The difference between the advisories and alerts and the large numbers that are quoted might be a variable from one center to another. My colleagues and I have some 40 units at risk in recall. Only two units have been replaced because of these recalls or advisories. With regard to the authors' recommendation that we need improved pacemaker standards, I think we have one of the best standard systems in the world, namely that of voluntary standards. The Association for Advancement of Medical Instrumentation has led the way for the development of these standards. The implementation of these standards by the FDA may contribute to the cause of our problems rather than the standards themselves. DR. DWIGHT E. HARKEN Cambridge. Mass.

The problem in the United States is perhaps not as great as has been pointed out by Dr. MacGregor. The tragedy of the person at risk is not to be denied. However, I should like to address the horror that plagues uninvolved patients and their families when the media releases headlines such as "heart pacemakers recalled," "heart valves recalled," or "hip prostheses recalled." I have appealed to the FDA and testified before congressional hearings along with Drs. Beall, Rainer, and others, who have been helpful in the formulation of the Device Act of 1976 (and I know that Act is far from perfect). We could only try to make the Act as reasonable as possible. Our Act requires the manufacturer to notify the purchaser when warned of a device failure-the purchaser not the physician (that is a mistake in Dr. MacGregor's table). There is no statement as to when the purchaser is to be notified. I have asked that the FDA withhold from the Federal Register the announcement that there will be a recall for 10to

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12 days until those at risk can be notified. If we can get Commissioner Kennedy to agree to this, we can say to our patients when we are putting in a heart valve, pacemaker, or whatever device, "If you see an announcement in the media that your device has been recalled, you know automatically that you are not involved." A 12 day delay in publication allows time for those at risk to be warned. We can thereby protect the 99.9 percent uninvolved patients from cruel and unmerciful inappropriate alarm. I am sure that many of your patients had unhappy experiences the week that a few Bjork-Shiley valves and Cordis pacemakers were withdrawn. My telephone switchboard looked like a Christmas tree. None of the people who called was involved. I submit that by minor delay reporting in the Federal Register we can spare the majority of patients unnecessary pain. DR. GEORGEJ. MAGOVERN Pittsburgh. Pa.

Over the past 4 years we have implanted some 75 nuclearpowered pacemakers made by three different manufacturers. Not one of these nuclear units has failed. The Atomic Energy Commission was in charge of the criteria for the components, as opposed to the FDA regulating the mercury battery, and the manufacturing and quality control requirements were much more stringent. The nuclear units, for instance, have to use higher reliability components. Many of the popular pacemakers do not, because the price differential is extremely different in building them. All nuclear units have to be able to withstand 5,000 gravity. They have to be able to withstand being dropped from an airplane; if the patient would happen to land on his chest, the nuclear unit would have to hit the ground and the battery not disintegrate. All units must withstand cremation, and all are hermetically sealed in a metallic encasement. I feel their over-all manufacture and their requirements for reliability are much better, and, that is the reason that the dependability to date, at least in our experience, has been so excellent. DR. HECTOR W. BENOIT, JR. Kansas City, Mo.

Our series is not so large as that of the Toronto group. We had approximately 15 percent recalls in the last 18 months dealing with only one manufacturer. When the second recall was announced, we realized that our reaction to the first recall was possibly overstressed. At the time of the first recall we replaced every unit which was at risk. The second time we were provided with a pulse inhibitor which gave us an oppor-

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tunity to test each of the patients whose unit was suspect. In those patients whose own rate was 60 beats per minute or more, we arbitrarily elected not to replace the unit and instead employed the telephone monitoring system. I have one question: How often should one check a unit that is suspect with the pacemaker inhibitor? We have all seen patients with varying degrees of heart block who, soon after pacing, will become totally dependent. Is there a likelihood that in time they will become more pacemaker dependent? We have tried to get an answer to this question through the manufacturers' consultants and have been unsuccessful. I would like to ask the authors if they have any recommendations to make to the Association regarding how often one should test the patient with a generator inhibitor. DR. MAc G REG 0 R (Closing) I would like to thank the discussers for their searching remarks. I agree with Dr. Morse that overdrive suppression of the pacemaker can be valuable in determining pacemaker dependency, but I would like to stress that this procedure should not be taken lightly and should be carried out with the patient under close surveillance. I have nothing further to add to Dr. Bailey's very pointed remarks. The position of a doctor who has a patient with a recall pacemaker must be clarified legally. In general, if the patient has been well looked after and if good communications have been maintained, the doctor will usually be freed of responsibility for the recall itself. In response to Dr. Rainer, I feel that we have not overreacted to our pacemaker recalls. We replaced only II recall pacemakers on the basis of manufacturers' recommendations. In retrospect, nine of these patients could probably have been closely monitored instead. I agree with Dr. Harken that the news media often instils fear and anxiety in our pacemaker patients and that a responsible press should resist the temptation to use unnecessary sensationalism when reporting on pacemaker recalls. Dr. Magovern referred to the reliability that can be built into pacemakers, as in the case of nuclear units. It should be the manufacturer's responsibility to build all pacemakers from the most reliable components available. Finally, with regard to Dr. Benoit's question, I feel that frequent overdrive suppression is difficult to accomplish in a large population of patients. The degree of dependency often becomes quite evident when a patient is on weekly transtelephone monitoring. Holter monitoring is an alternative method of surveillance but, again, it only can be used for a limited number of patients at anyone time.