cardiac pacing in retrospect

7
Cardiac Pacing in Retrospect Ake Senning, MD, Zurich, Switzerland As early as 1580, Mercuriale Geronimo [1] of Padua, Italy described synope associated with a slow pulse or the typical Adams-Stokes attack A century later in 1682, Gherbezio Marco [2], and 50 years earlier, Morgagni [3] reported the same phenomenon. These clinical observations were recorded more than 100 years before Galvani [4], a physiologist and surgeon, discovered the fundamentals of electrical stimulation of the heart in 1791. Seven years later in 1798, Bichat [5] in Paris examined hearts of decapitated men and showed that human hearts reacted to electrical stimuli. Finally in 1804, Vasalli [6] in Turin, Italy pointed out the necessity of ventilating the lungs when stimulating the heart for resuscitation . During the 19th century, mainly German and Dutch physi- ologists expanded the knowledge of how to record the myocardial reaction of electric stimuli; the Swiss investigators Prevost and Battelli [7] worked out the problem of ventricular fibrillation and defibrilla- tion. The first successful cardiac resuscitation by elec- trical stimulation dates back to 1774, according to the Royal Humane Society of London. A child having been declared irrevocably dead by a physician after a fall was brought back to life 20 minutes later by the application of faradic current through the closed chest by a man named Squires. The first precursor of an artificial pacemaker for resuscitation was presented in 1929 by Mark Lidwill [a], an anesthesiologist from Sydney, Australia. In association with E. A. Booth, Lidwill’s group devel- oped a portable electrical pacemaker that could be connected to a light current power source. One pole was applied to a skin pad soaked with saline solution and the other, consisting of an insulated needle with a bare tip, was plunged into the heart. The pace- maker rate was variable, from 80 to 120 beats/min, and the voltage ranged from 1.5 to 120 volts. Ap- From the Surgical Clinic A, University Hospital, Zurich, Switzerland. Requests for reprints should be addressed to Ake Senning, MD, Surgical Clinic A, University Hospital, Raemistrasse 100, Zurich, Switzerland, Presented at the Eighth Annual Lyman A. Brewer III Cardiothoracic Symposium, Los Angeles, California, December 8 and 9, 1982. proximately 10 volts were found to be necessary for stimulation. This apparatus was successfully used on a few stillborn infants for whom “everything else” had been tried before. In 1932, Hyman [9] reported another portable machine made by Dr. E. Parsonnet. It consisted of a magnetic generator which weighed 7.2 kg and was similar to the “magnets” of old motor bikes. A spring motor could spin the generator for 6 minutes, and the pulse frequency could be fixed at 30,60, or 120 impulses per minute. The left ventricle was stimulated by a transcutaneously introduced special needle with a noninsulated bare tip. My first experience with cardiac arrhythmia was unforgettable. I had built a radio with a double-grid vacume tube in the amplifier, and by chance I was able to hear Lindberg’s landing in his Spirit of St. Louis in Paris in 1927. My father translated to me what was happening. Shortly afterwards, while doing my school homework, I noticed a buzz in the radio each time I touched the iron lamp on my table. Once I grapped the ground wire with the other hand. The effect was sensational. The lamp fell on the floor and I had a feeling my heart had stopped for a long time. The 220 volts of AC current from the lamp had probably caused a short period of ventricular fibril- lation. Twenty years later I introduced ventricular fibrillation [IO] to get a functional cardiac standstill during extracorporeal circulation to facilitate open heart surgery with precision and to prevent air em- bolism. In 1951, while discussing a paper by Joungblood in Paris, I presented the first two dogs surviving about 1 hour after open heart surgery. Jack Gibbon corrected my English and Bill Bigelow [II], while drinking a pastice with me, told about the artificial pacemaker developed by Callaghan and Bigelow [12]. To avoid a thoracotomy, the sinus nodal area of hy- pothermic dogs was stimulated by intravenously introduced electrodes set at a desired frequency. Callaghan [13] had first been asked to clinically apply this method in 1949. The results were unfortunately not successful because he did not introduce the electrode into the ventricle. This information was helpful to me in coping with asystole or bradycardia Volume 145, June 1983 733

Upload: aeke-senning

Post on 17-Oct-2016

220 views

Category:

Documents


0 download

TRANSCRIPT

Cardiac Pacing in Retrospect

Ake Senning, MD, Zurich, Switzerland

As early as 1580, Mercuriale Geronimo [1] of Padua, Italy described synope associated with a slow pulse or the typical Adams-Stokes attack A century later in 1682, Gherbezio Marco [2], and 50 years earlier, Morgagni [3] reported the same phenomenon. These clinical observations were recorded more than 100 years before Galvani [4], a physiologist and surgeon, discovered the fundamentals of electrical stimulation of the heart in 1791. Seven years later in 1798, Bichat [5] in Paris examined hearts of decapitated men and showed that human hearts reacted to electrical stimuli. Finally in 1804, Vasalli [6] in Turin, Italy pointed out the necessity of ventilating the lungs when stimulating the heart for resuscitation . During the 19th century, mainly German and Dutch physi- ologists expanded the knowledge of how to record the myocardial reaction of electric stimuli; the Swiss investigators Prevost and Battelli [7] worked out the problem of ventricular fibrillation and defibrilla- tion.

The first successful cardiac resuscitation by elec- trical stimulation dates back to 1774, according to the Royal Humane Society of London. A child having been declared irrevocably dead by a physician after a fall was brought back to life 20 minutes later by the application of faradic current through the closed chest by a man named Squires.

The first precursor of an artificial pacemaker for resuscitation was presented in 1929 by Mark Lidwill [a], an anesthesiologist from Sydney, Australia. In association with E. A. Booth, Lidwill’s group devel- oped a portable electrical pacemaker that could be connected to a light current power source. One pole was applied to a skin pad soaked with saline solution and the other, consisting of an insulated needle with a bare tip, was plunged into the heart. The pace- maker rate was variable, from 80 to 120 beats/min, and the voltage ranged from 1.5 to 120 volts. Ap-

From the Surgical Clinic A, University Hospital, Zurich, Switzerland. Requests for reprints should be addressed to Ake Senning, MD, Surgical

Clinic A, University Hospital, Raemistrasse 100, Zurich, Switzerland, Presented at the Eighth Annual Lyman A. Brewer III Cardiothoracic

Symposium, Los Angeles, California, December 8 and 9, 1982.

proximately 10 volts were found to be necessary for stimulation. This apparatus was successfully used on a few stillborn infants for whom “everything else” had been tried before. In 1932, Hyman [9] reported another portable machine made by Dr. E. Parsonnet. It consisted of a magnetic generator which weighed 7.2 kg and was similar to the “magnets” of old motor bikes. A spring motor could spin the generator for 6 minutes, and the pulse frequency could be fixed at 30,60, or 120 impulses per minute. The left ventricle was stimulated by a transcutaneously introduced special needle with a noninsulated bare tip.

My first experience with cardiac arrhythmia was unforgettable. I had built a radio with a double-grid vacume tube in the amplifier, and by chance I was able to hear Lindberg’s landing in his Spirit of St. Louis in Paris in 1927. My father translated to me what was happening. Shortly afterwards, while doing my school homework, I noticed a buzz in the radio each time I touched the iron lamp on my table. Once I grapped the ground wire with the other hand. The effect was sensational. The lamp fell on the floor and I had a feeling my heart had stopped for a long time. The 220 volts of AC current from the lamp had probably caused a short period of ventricular fibril- lation. Twenty years later I introduced ventricular fibrillation [IO] to get a functional cardiac standstill during extracorporeal circulation to facilitate open heart surgery with precision and to prevent air em- bolism.

In 1951, while discussing a paper by Joungblood in Paris, I presented the first two dogs surviving about 1 hour after open heart surgery. Jack Gibbon corrected my English and Bill Bigelow [II], while drinking a pastice with me, told about the artificial pacemaker developed by Callaghan and Bigelow [12]. To avoid a thoracotomy, the sinus nodal area of hy- pothermic dogs was stimulated by intravenously introduced electrodes set at a desired frequency. Callaghan [13] had first been asked to clinically apply this method in 1949. The results were unfortunately not successful because he did not introduce the electrode into the ventricle. This information was helpful to me in coping with asystole or bradycardia

Volume 145, June 1983 733

Senning

Figure 7. The first pacemaker in 1958 (insert), and a patient Mh the charging coil and frequency generator. Reprinted from Pm Roy Sot Med 1961;54:273-91 with permIssIon from the publisher,

after defibrillation of dog hearts following prolonged cardiopulmonary bypass. I constructed an apparatus (something between a ringing bell and an old electric clock) to stimulate the ventricles to contract.

In 1952, Zoll[14] introduced an apparatus with a variation of Callaghan’s pacemaker circuit. He used it for external pacing of patients with Adams-Stokes attacks. The pacemaker was bulky and the electrodes caused unpleasant sensations on the skin and skeletal muscle, and contraction, burns, and infection. It thus was not applicable for long-term use.

While visiting Minneapolis in 1957, I was Walt Lillehei suturing stainless steel electrodes to the ventricle to transcutaneously stimulate a child’s heart which had an iatrogenic total atrioventricular block after ventricular septal defect closure. This method lacked the drawbacks of the Zoll pacemaker: I consider it the beginning of the era of clinical pacing [151.

After my return to Stockholm, we studied this method experimentally and clinically. While Med- tronic (Minneapolis, MN) manufactured an external pacemaker for Lillehei’s team, Elmquist, who was working at Elema-Schonander, constructed one for us in Stockholm. There were, however, some major disadvantages: the inconvenience of carrying the pacemaker externally; the steady rise of the thresh- old; and the danger of infection along the wire elec- trodes, which would cause local abscesses, disloca- tions, sepsis, and finally death. For me the solution to these problems was to implant the entire pace- maker. When a silicone transistor became available

734

in 1956, the pacemaker could be built small enough for this purpose. In 1957 an experimental series was started. At the same time, together with Dr. Elmquist [16], the electrical parameters important for clinical cardiac stimulation were studied in patients with external pacemakers.

Because ventricular stimulation at fixed rates al- lows variation of cardiac index by only changing stroke volume, we investigated cardiac performance at variable pulse rates and found 72 beats/min to be optimal with respect to energy loss of the pacemaker and acceptable cardiac indexes. It was hard work at that time as these studies had to be performed using the Fick principle to determine the cardiac index and Van Slyke’s method to analyze the blood samples. In addition, the impedance over the heart and the necessary duration in correlation with the amplitude of the stimulus had to be defined as did other factors. We were hoping the pacemaker would last for several years and were looking for a longlasting energy source. We finally chose two nickel cadmium re- chargable cells with 60 milliamperes per hour con- nected in series. This gave three times the estimated voltage for an impulse of 1.5 ms. Overnight once a month the pacemaker batteries were charged over a coil connected through a silicone diode which was placed over the pacemaker. The inductive current in this coil came from a 150 kHz radio frequency gen- erator (Figure 1). The first model had two leads which consisted of twinned stainless steel wires with polyethylene insulation. The dog experiments seemed successful, but because of insufficient long-

The American Journal of Surgery

Cardiac Pacing in Retrospect

Figure 2. Elwctrocardiogram during tmptantatton of the f/ret pacemaker (October 8, 7958).

term data, I did not consider the pacemaker ready for clinical use when we were suddenly forced to implant the first one in a patient.

The patient was a 43 year old man who had hepa- titis and myocarditis with a total atrioventricular block due to a virulant infection. He had been hos- pitalized for 6 months and suffered increasingly frequent Adam-Stokes attacks. During the few days before pacemaker implantation, he had to be resus- citated up to 30 times per day. His wife begged us to try to help him by implanting our new pacemaker system. Dr. Elmquist rigged up circuits for two pacemakers and molded them in epoxy resin in a shoe wax can measuring 55 mm in diameter and 15 mm in height. I implanted the two electrodes into the myocardium (Figure 2) through a thoracotomy and the pacemaker into the posterior rectus sheath (Figure 3). At 2 AM the pacemaker became silent, and the next morning the second one was implanted. Nine weeks later, I wrote that it functioned well with a rate of 64 beats/min. Although this unit prematurely ceased to stimulate, the patient did not suffer any more Adams-Stokes attacks and he is still living, presently with his 23rd pacemaker. He is very active and among many other activities he is presi-

dent of the Swedish Association for Heart and Lung Disease.

It became clear to me that we had to find better methods for long-term stimulation of atrioventricular blocks. The steady increase of the stimulation threshold of the stainless steel wire was one limiting factor. Therefore, a new flexible electrode lead of four thin stainless steel bands around a polyethylene thread insulated by soft polyethylene was developed and connected to a small platinum plate which was then sutured to the heart. After this development, the increasing stimulation threshold ceased being a problem. A forced stress test arranged by the first patient at the Technical Institute of Stockholm showed that it lasted for more than 184 million cycles or for at least 6 years, Several patients have this type of electrode today for more than 15 years without trouble.

In 1959, Dr. Elmquist and the Elema-Shonander factory produced the Elema 135 pacemaker; two of these were successfully implanted in Stockholm during that year. In April 1960, Siddons [2 71 in En- gland implanted two or three pacemakers. The ex- ternal charging, however, was too complicated, par- ticularly for elderly patients; therefore, in 1960, the

Volume 145, June 1983 735

Senning

F@re 3. Pacemaker implanted in the posterior muscle sheath (October IO. 1958).

Elema 137 with mercury cells came on the market. One side of this pacemaker functioned as the indif- ferent electrode, while the stimulating one was su- tured to the epicardium. Although only one wire had to be placed, we continued to implant two for safety reasons. In 1960, pacemakers of this kind were suc- cessfully implanted, and during the same year Chardack et al [18] started the U.S. World Series with a built-in pacemaker designed by Greatbach. They were using bipolar electrodes in the myocar- dium with two stainless pins mounted on a silicone plate.

American, Swedish, and other European manu- facturers now started to compete in developing more and more elaborate pacemakers. Also, cardiologists became convinced of their beneficial use. The num- ber of implanted pacemakers rose from 1 in 1958 and 2 in 1959 to more than 100,000 by 1981. Over the years, the implantation technique has changed and electrode placement has been greatly simplified. The transvenous route, suggested and practiced by Cal- laghan and Bigelow [12] in 1949 was refined in 1958 in two patients by Furman and Schwedel [19]. My team colleagues at the clinic in Stockholm, Ekestmm, Johansson, and Lagergren [20], first connected a transvenous electrode to an implanted pacemaker in 1962. In 1965 there were already 305 patients in Eu- rope having their pacemaker implanted without thoracotomy [21].

The next step forward in the development of

modern pacemakers was published in 1963 by the members of the same team. They implanted an atrial triggered synchronous pacemaker in a patient with- out thoracotomy. Carlens et al [22] placed the sensing electrodes through a mediastinoscopy after a delay of about 100 ms up to a pulse rate of 140 beats/min. Independently, Nathan et al [23] in November 1962 had already done the same in an experimental model.

The most serious drawback of all of these pace- makers was that their batterylife was much shorter than anticipated, and certainly many patients died because the triggering stopped prematurely. Several methods to record the actual energy level in our pacemaker system was a decreasing pulse rate, but often a patient did not realize the change in heart rate. It was also found that the energy reverse could be checked by roentgenography. In addition, it was my impression that epoxy resin was not the appro- priate material to prevent current leak in the circuit after implantation. In 1968 I convinced Dr. Babotai in our lab in Zurich to build a pacemaker completely incapsulated in metal. It consisted of only three batteries with the electronic circuit at the bottom of a 7 cm long brass tube. This brass tube was galvanicly covered with a layer of gold to make it inert to tissue (Figure 4). Fifty-five of these pacemakers were im- planted with an average survival of 3 years, and the best pacemaker triggered 4.2 years. The hermetically sealed metallic pacemaker cover became standard approximately 10 years ago.

A further problem was that the fixed rate often interfered with the patient’s own rhythm. Sometimes repetitive firing occurred and several patients suc- cumbed to ventricular fibrillation caused by stimu- lation in the vulnerable phase of late systole. In 1964 Castellanos et al [24] showed a circuit for R-wave inhibition, the on-demand pacemaker, and Neville et al [25] in 1966 designed the R-wave triggered mechanism. Both of these sensing modes resolved the most serious problem of fixed rate pacemakers. Fi- nally, Berkovits et al [26] in 1969 reported biofocal demand pacing.

With the enormous development in electronics, the circuits changed from discrete and hybrid ones, to integrated thin and thick film circuits, to micropro- cessors. At the same time the pacemakers became progressively smaller. In 1972, lithium batteries were introduced by Cardiac Pacemaker, Inc. (Minneapo- lis). Thus, more energy could be stored and the pro- gramming possibilities increased from the simple invasive change in rate and voltage (Medtronic 1960) to external adjustments in sensitivity, refractory period, and mode of sensing and intensity. At the same time, the survival of pacemakers increased from days, weeks, or months in 1958 to an 84 to 93 percent 5 year survival rate in the last generation of pace- makers [27]. Telemetry now allows monitoring of pacemaker parameters at a great distance. Today,

736 The American Journal of Surgery

Cardiac Pacing in Retrospect

Figure 4. Different types of pacemakers in epoxy resin (developed since 1968) and the hermetically sealed pacemaker (lower left). Bottom, the three batteries and the elecbvnlc clrcult of the hermetl- tally sealed pacemaker.

sophisticated electrophysiologic studies have better defined the indications for the various pacemaker systems presently available. We now have at our disposal not only models to correct atria1 and ven- tricular arrhythmias [28], but also models for inter- ruption of ventricular fibrillation. On the other hand, programmable pacemakers have become too com- plicated to play with for the ordinary physician or cardiac surgeon. Having witnessed the enormous development of pacemakers in the past 5 years, we are hopeful that the future will bring not only long- lasting, self-adjusting pacemakers, but perhaps systems and models equipped with sensors to mon- itor physiologic and chemical changes in the body fluid.

There are, however, other problems still to be solved. For example, a more reliable transfer of the electrical stimulus from pacemakers to the heart and vice versa. The many models of electrodes available today prove that none is perfect (Figure 5). To reduce the early dislocation rate (occurring in about 5 to 10 percent, according to Parsonnet et al [29]), a perfect electrode with a grasping or entrapping mechanism for atria1 and ventricular placement still has to be designed. A smaller and more inert electrode tip

Volume 145, June 1993

would also allow a shorter impulse duration and di- minish energy loss. Furthermore, the energy source can be improved or perhaps tissue batteries used, and I personally hope that the last plutonium pacemaker died with Breshnev.

Summary

As precursors of permanent pacemakers, Lidwill (1929) and Hyman (1932) introduced temporary pacemakers for resuscitation. Callaghan (1950) in- travenously paced the sinus nodal region for brady- cardia in hypothermic dogs. Zoll(1952) used external electrodes to treat Adams-Stokes attacks, and Lil- lehei (1957) fixed stainless steel electrodes to the myocardium, successfuly treating iatrogenic total atrioventricular block with a percutaneous pace- maker.

Since 1951, by experimental and clinical use of ventricular fibrillation to obtain a functional cardiac standstill during open heart surgery, we used all known methods of stimulation to treat asystole or bradycardia after defibrillation. Since 1957, percu- taneous stimulation by Adam-Stokes attacks has been performed. The most serious complication is infections along the electrodes causing death from

737

Senning

sepsis. The solution of the problem was the implan- tation of the pacemaker and its energy supply. Per- cutaneous leads were used to study the different parameters for electric stimulation and to find the lowest frequency (to spare energy) with the best variation of cardiac output. In October 1958 in Stockholm a fixed rate pacemaker was implanted by thoracotomy. At present, the patient is living with his 23rd pacemaker. Four additional patients had pacemaker implantations until 1960. In 1961, Chardack and Greatbach successfully implanted pacemakers with mercury batteries. Johanson and Lagergren connected the pacemaker to an intrave- nous electrode to avoid thoracotomy. The enormous development in the electronic field made more elaborate pacemakers possible, and eliminated the risk of the fixed rate (interference, repetitive firing, and ventricular fibrillation).

1. Geronimo Mercuriale (Praelectiones Patavinae). De Cognos- cendis et curandis humani corporis affectibus (Venezia 1606), opera postuma, 238, 242, 243.

Gherbezio Marco. Ephemeridum medico-physicarum germa- nicarum academiae naturae curiosorum 1683, Norimberga 1698.

16. Elmquist R, Senning A. Implantable-pacemaker for the h&t. Medical Electronics. Proceedings of the Second International Conference on Medical Electronics, Paris, June 1959.

17. Siddons AHM. Complete heart block with Stokes-Adams attacks treated by indwelling pacemakers. Proc R Sot Med 1961; 54:237-91.

2.

Morgagni Giovan Battista. De sedibus et cusis morborum per antomen indagatis. Venezia 1761.

Galvani L. De viribus electricitatis in motu musculari com- mentarius. Bologna lnstit Scient 177 1.

Bichat XS. Recherches physiologiques sur la vie et la mort. Paris: Brosson, Gabon & Cie, 1800.

Vasalli. In: Aldini J, ed. Essai theorique et experimental sur la galvanisme avec une serie d’esperiences. Paris: Fournier, 1804.

18. Chardack WM. Gage AE, Greatbatch W. A transistorized self- contained implantable pacemaker for long term correction of complete heart block. Surgery 1960;48:643-8.

19. Furman S, Schwedel JB. An intracardiac pacemaker for Stokes-Adam seizures. N Engl J Med 1959;261:943-8.

20. Ekestrom S, Johansson L, Lagergren H. Behandling av Adam Stokes syndrom med intracardiell pacemakerelectrod. Op- uscula Medica 1962;7: 175-6.

21. Lagergren H, Johansson L, Karlof I, Thornander H. Atrial triggered pacemaking without thoracotomy. Apparatures and results in twenty cases. Acta Chir Stand 1966;132:678- 95.

7. Prevost JL, Battelli F. Quelques effects des decharges Bletri- 22. Carlens E, Johansson L, Karlof I, Lagergren H. New method for

738 The American Journal of Surgery

References

Figure 5. The Elema 137 pacemaker ( 1960) w/t/t the /nd/ffefent e/e&ode on the pacemaker ami a platfnum-plafe stfmdatlng ehvcttvds, A second ebctmds is implanted In reserve for safety rea- sons.

ques sur le coeur des mammiferes. J Physiol Path G&I 1900;2:40-1.

8. Lidwill MD, Mond HG, Sloman GJ, Edwards RH. The first pacemaker. Pace 1982;5:278-81.

9. Hyman AS. Resuscitation of the stopped heart by intracardial therapy. Experimental use of an artificial pacemaker. Arch Intern Med 1932;50:283-305.

10. Senning A. Ventricular fibrillation used as a method to facilitate intracardiac operations. Acta Chir Stand 1952; (suppl)172.

11. Bigelow WG, Callaghan JC, Hopps JA. General hypothermia for experimental intracardiac surgery. Ann Surg 1950; 132531-g.

12. Callaghan JC, Bigelow WG. Electrical artificial pacemaker for standstill of the heart. Ann Surg 1951;134:8-17.

13. Callaghan JC. Early experience in the study and development of an artificial electrical pacemaker for standstill of the heart. View from 1949. Pace 1980;3:618-9.

14. 2011 PM. Resuscitation of the heart in ventricular standstill by external stimulation. N Engl J Med 1952;247:768.

15. Weirich WL, Gott VL, Lillehei CW. The treatment of complete heart block by the combined use of a myocardial electrode and an artificial oacemaker. Suro Forum 1957;6:360-3

Cardiac Pacing in Retrospect

arterial triggered pacemaker treatment without thoracotorny. J Thorac Cardiovasc Surg 1965;50:229-37.

23. Nathan D, Center S. Wu ChY, Keller W. An implantable syn- chronous pacemaker for the long term correction of com- plete heart block, Am J Cardiol 1963; 11:362-71.

24. Castellanos A Jr, Lemberg L, Berkovits BV. The “demand” cardiac pacemaker: a new instrument for the treatment of a-v conduction disturbances. Inter Am Coil Cardiol Meeting, Montreal, June, 1964.

25. Neville JF, Millar K, Keller W, Abildskov JA. An implantable demand pacemaker. Clin Res 1966;14:256-8.

26. Berkovits BV, Castellanos A Jr, Lemberg L. Bifocal demand pacing. Circulation 1969;39:44-52.

27. Bilitch M, Hauser RG, Goldman BS, et al. Performance of car- diac pacemaker pulse generators. Pace 1982;5:465-8.

26. Hartzler GO, Holmes DR, Osborn MJ. Patient-activated transvenous cardiac stimulation for treatment of supraven- tricular and ventricular tachycardia. Am J Cardiol 1981; 49:903-g.

29. Parsonnet V, Bilitch M, Furman S, et al. Early malfunction of transvenous pacemaker electrodes. A three-center study. Circulation 1979;60:590-6.

Volume 145, June 1983 739