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New method for atrial-triggered pacemaker treatment without thoracotomy
New method for atrial-triggered pacemaker treatment without thoracotomy E. Carlens, M.D., L. Johansson, M.D., l. Karlöf, M.D., and H. Lagergren, M.D., Stockholm, Sweden
Stimulation with an artificial pacemaker is now an accepted form of treatment in cases of Adams-Stokes syndrome in which medication is unable to produce any lasting improvement.1' As a rule, a portable pacemaker with fixed frequency has been used,3"6 although various kinds of adjustable apparatus have also been reported.7' 8>9 The electrodes for stimulating the myocardium have been placed in contact either with the epicardium, via a thoracotomy, or with the endocardium by being advanced through a suitable vein.10' "■ 12 In view of its ease, the latter method has certain advantages, as the pa tients most often are elderly and severely ill. Experience gained in a large series has shown, however, that an apparatus with fixed frequency, whose rhythm is completely independent of the atrial activity, is not suitable in every case. It may, for example, be desirable to have a pacemaker triggered by the atrial frequency in patients with pre ponderantly sinus rhythm in whom a com plete block appears only occasionally. Furthermore, in certain patients with heart block, it may be appropriate to increase the stroke volume by synchronizing atrial and From the Surgical Thoracic Clinic and Physiological Laboratory, Thoracic Clinics, Karolinska Sjukhuset, Stockholm, Sweden. Received for publication March 8, 1965.
ventricular systole. A special atrial-triggered pacemaker has been designed for these cases.13 Via a "detector" electrode in con tact with the atrium, the electrical activity corresponding to the P wave is led off and triggers the pacemaker; the latter, after a certain delay, stimulates the ventricular myocardium via two other electrodes. Ap plication of these electrodes has formerly necessitated thoracotomy and suture of the atrial and ventricular electrodes in place. In order to avoid the drawbacks of thoracot omy, we have devised a method for atrialtriggered pacemaker treatment which differs from those suggested earlier.14 Conventional intracardiac stimulation Electrodes for conventional intracardiac pacemaker treatment are first applied, ac cording to a method previously described.11 This is done under local anesthesia or with the patient under light intubation anesthesia. An indifferent electrode is introduced subcutaneously below the left margin of the thorax, after which the electrode cable is drawn down toward the right groin with the help of a long, thick injection needle. An incision is then made over the region of the jugular vein, preferably on the right side, and the external or internal jugular vein is exposed. The intracardiac electrode is in troduced through the exposed vessel and, 229
230
Carlens et al.
Journal of Thoracic and Cardiovascular Surgery
under roentgen visual control, its tip is placed in the apex region of the right ven tricle, where it becomes anchored in the trabecular network. When the electrode has been sutured in a few loops in the tissues of the neck, the rest of the cable is drawn down subcutaneously, behind the clavicle, over the chest and abdomen to the right groin. The electrodes are connected to an external, battery-driven pacemaker, which is carried in a strap over the shoulder.
When the patient has had the pacemaker functioning for a certain time, there are two possibilities. He can either continue to use an external apparatus, or the cables can be cut at the site where they lie sterile in the subcutaneous tissue and he can be provided with a pacemaker implanted subcutaneously. Experience with about 100 cases of such electrodes placed intracardially has been favorable, and in no instance have we ob served endocardial damage, thrombosis, or tricuspid incompetence. An account of this case material is now in preparation. Atrial-triggered pacemaker treatment
Fig. 1. Detector electrode.
Material. In addition to the aforemen tioned conventional electrodes, a "detector" electrode is used. Its construction is the same as that of an intracardiac stimulating electrode. The electrode cable, which is ex tremely soft and flexible and about 1.5 meters long and 1 mm. in diameter, consists of a spun textile core around which four thin strips of stainless steel have been wound. It has an insulating covering of
Fig. 2. Lateral (A) and frontal (B) views of both electrodes in position (indifferent electrode in front).
Volume 50 Number 2 August, 1965
Atrial-triggered pacemaker treatment
231
Fig. 3. Upper tracing: Electrocardiographic standard Lead II. Lower tracing: Size and shape of P-wave lead-off between atrial electrode and indifferent electrode.
Vu
Fig. 4. Atrial-triggered ventricular rhythm.
polythene. The electrode tip is a cylin drical platinum knob, 10 mm. long and 3 mm. in diameter (Fig. 1). The "detector" electrode, like the stimulating electrodes, is connected to a specially constructed ap paratus for atrial-triggered pacemaker treat ment. For preliminary evaluation of the thera peutic results as well as the scientific pur poses, we used a commercial apparatus for heart resuscitation manufactured by Corbin Farnsworth, Inc., Palo Alto, Calif. After certain modifications, the pacemaker unit of this apparatus was able to give impulses synchronously with the P wave. The possi bility also exists of varying the conduction time and blocking time. For permanent treat ment, an tmplantable atrial-triggered pace
maker has newly been designed in collabora tion with the Elema-Schönander Co., Stock holm, Sweden. Method. After the patient has been pro vided with conventional intracardiac and indifferent electrodes, and these have been connected to a pacemaker with fixed fre quency, the indications for atrial-triggered pacemaker treatment are considered. If such indications exist, the "detector" electrode is placed on the atrium by means of mediastinoscopy.ir' Under intubation anesthesia and after administration of a muscular re laxant, a small incision is made in the jugular fossa and one dissects along the trachea. Through the mediastinoscope, dis section is continued, under visual control, past the point of bifurcation of the trachea
Journal of
2 32
Carlens et al.
Thoracic and Cardiovascular Surgery
and the right branch of the pulmonary ar tery, to reach the thin layer of connective tissue between the posterior wall of the atrium and the esophagus. When this region has been localized, the electrode tip is ad vanced and placed, with the aid of a forceps, in the connective tissue, as close as possible to the atrial wall, while the amplitude of the P wave is checked on the electrocardio gram. The mediastinoscope is then removed, and the electrode cable is drawn down subcutaneously, with the help of a long injec tion needle, over the chest and abdomen to the right groin. The incision in the neck is then closed. This intervention, with which we now have considerable experience, places extremely little strain on the patient, who can become ambulant on the same day. The "detector" electrode placed in this way is firmly anchored (Fig. 2 ) . The risk of infection is eliminated by the long sub cutaneous tunnel. The P wave, led off be tween the "detector" electrode and the in different electrode, is of the magnitude of at least 1.5 mv., and remains stable (Fig. 3 ) . In this type of transmission, the size of the P wave suffices for regular triggering of the unit which in turn gives impulses to the ventricular electrode (Fig. 4 ) . The con figuration of the P wave is unaffected by movements of the body, swallowing, and the respiratory excursions. With this method one can either connect the electrodes to an external apparatus or sever them where they lie sterile in the subcutaneous tissue, and provide the patient with a pacemaker implanted in this site.
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Summary
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A method is described for application of electrodes to an atrial-triggered pacemaker without thoracotomy. An account will be given later of the indications, therapeutic results, and hemodynamics as well as an ac count of the new implantable pacemaker.
14
REFERENCES 1 Landegren, J., and Biörck, G.: The Clinical Assessement and Treatment of Complete
15
Heart Block and Adams-Stokes Attacks, Medi cine 42: 171, 1963. Diamond, E. G., Bay, E. B., Chardack, W. M., Dack, S., and Zoll, P. M.: Heart Block: Mech anism and Management, Dis. Chest 43: 456, 1963. Chardack, W. M., Gage, A. A., Federico, A. J., Schimert, G., and Greatbatch, W.: Clinical Experience With an Implantable Pacemaker, Ann. New York Acad. Sc. I l l : 1075, 1964. Zoll, P. M., Frank, H. A., and Linenthal, A. J.: Implantable Cardiac Pacemakers, Ann. New York Acad. Sc. I l l : 1068, 1964. Kantrowitz, A.: Implantable Cardiac Pace makers, Ann. New York Acad. Sc. I l l : 1049, 1964. Elmqvist, R., Landegren, J., Pettersson, S. O., Senning, Â., and William-Olsson, G.: Artificial Pacemaker for Treatment of Adams-Stokes Syndrome and Slow Heart Rate, Am. Heart J. 65: 731, 1963. Widman, W. D., Glenn, W. W. L., Eisenberg, L., and Mauro, A.: Radiofrequency Cardiac Pacemakers, Ann. New York Acad. Sc. I l l : 992, 1964. Norman, J. C , Lightwood, R., and Abrams, L. D.: Surgical Treatment of Adams-Stokes Syndrome Using Long-Term Inductive Cou pled Coil Pacemaking, Ann. Surg. 159: 344, 1964. Cammilli, L., Pozzi, R., and Drago, G.: Re mote Heart Stimulation by Radio Frequency for Permanent Rhythm Control in the Morgagni-Adams-Stokes Syndrome, Surgery 52: 765, 1962. Schwedel, J., and Escher, O. J. W.: Transvenous Electrical Stimulation of the Heart, Ann. New York Acad. Sc. I l l : 972, 1964. Lagergren, H., and Johansson, L.: Intracardiac Stimulation for Complete Heart Block, Acta Chir. Scand. 125: 562, 1963. Parsonnet, W., Zucher, I. R., Gilbert, L., and Meyers, G. H.: A Review of Intracardiac Pacing With Specific Reference to the Use of a Dipolar Electrode, Progr. Cardiovas. Dis. 6: 472, 1964. Nathan, D . A., Center, S., Samet, P., Yu Wu, C , and Keller, J. W., Jr.: The Applica tion of an Implantable Synchronous Pacer for the Correction of Stokes-Adams Attacks, Ann. New York Acad. Sc. I l l : 1093, 1964. Rodewald, G., Giebel, H., Harms, H., and Scheppokat, K. D.: Intravenös-intracardiale Applikation von vorhofsgesteuerten elektris chen Schrittmachern, Ztschr. Kreislaufforsch. 53: 860, 1964. Carlens, E.: Mediastinoscopy: A New Method for Inspection and Tissue Biopsy in the Su perior Mediastinum, Dis. Chest 36: 343, 1959.
Stimulation with an artificial pacemaker is now an accepted form of treatment in cases of Adams-Stokes syndrome in which medication is unable to produce any lasting improvement.1' As a rule, a portable pacemaker with fixed frequency has been used,3"6 although various kinds of adjustable apparatus have also been reported.7' 8>9 The electrodes for stimulating the myocardium have been placed in contact either with the epicardium, via a thoracotomy, or with the endocardium by being advanced through a suitable vein.10' "■ 12 In view of its ease, the latter method has certain advantages, as the pa tients most often are elderly and severely ill. Experience gained in a large series has shown, however, that an apparatus with fixed frequency, whose rhythm is completely independent of the atrial activity, is not suitable in every case. It may, for example, be desirable to have a pacemaker triggered by the atrial frequency in patients with pre ponderantly sinus rhythm in whom a com plete block appears only occasionally. Furthermore, in certain patients with heart block, it may be appropriate to increase the stroke volume by synchronizing atrial and From the Surgical Thoracic Clinic and Physiological Laboratory, Thoracic Clinics, Karolinska Sjukhuset, Stockholm, Sweden. Received for publication March 8, 1965.
ventricular systole. A special atrial-triggered pacemaker has been designed for these cases.13 Via a "detector" electrode in con tact with the atrium, the electrical activity corresponding to the P wave is led off and triggers the pacemaker; the latter, after a certain delay, stimulates the ventricular myocardium via two other electrodes. Ap plication of these electrodes has formerly necessitated thoracotomy and suture of the atrial and ventricular electrodes in place. In order to avoid the drawbacks of thoracot omy, we have devised a method for atrialtriggered pacemaker treatment which differs from those suggested earlier.14 Conventional intracardiac stimulation Electrodes for conventional intracardiac pacemaker treatment are first applied, ac cording to a method previously described.11 This is done under local anesthesia or with the patient under light intubation anesthesia. An indifferent electrode is introduced subcutaneously below the left margin of the thorax, after which the electrode cable is drawn down toward the right groin with the help of a long, thick injection needle. An incision is then made over the region of the jugular vein, preferably on the right side, and the external or internal jugular vein is exposed. The intracardiac electrode is in troduced through the exposed vessel and, 229
230
Carlens et al.
Journal of Thoracic and Cardiovascular Surgery
under roentgen visual control, its tip is placed in the apex region of the right ven tricle, where it becomes anchored in the trabecular network. When the electrode has been sutured in a few loops in the tissues of the neck, the rest of the cable is drawn down subcutaneously, behind the clavicle, over the chest and abdomen to the right groin. The electrodes are connected to an external, battery-driven pacemaker, which is carried in a strap over the shoulder.
When the patient has had the pacemaker functioning for a certain time, there are two possibilities. He can either continue to use an external apparatus, or the cables can be cut at the site where they lie sterile in the subcutaneous tissue and he can be provided with a pacemaker implanted subcutaneously. Experience with about 100 cases of such electrodes placed intracardially has been favorable, and in no instance have we ob served endocardial damage, thrombosis, or tricuspid incompetence. An account of this case material is now in preparation. Atrial-triggered pacemaker treatment
Fig. 1. Detector electrode.
Material. In addition to the aforemen tioned conventional electrodes, a "detector" electrode is used. Its construction is the same as that of an intracardiac stimulating electrode. The electrode cable, which is ex tremely soft and flexible and about 1.5 meters long and 1 mm. in diameter, consists of a spun textile core around which four thin strips of stainless steel have been wound. It has an insulating covering of
Fig. 2. Lateral (A) and frontal (B) views of both electrodes in position (indifferent electrode in front).
Volume 50 Number 2 August, 1965
Atrial-triggered pacemaker treatment
231
Fig. 3. Upper tracing: Electrocardiographic standard Lead II. Lower tracing: Size and shape of P-wave lead-off between atrial electrode and indifferent electrode.
Vu
Fig. 4. Atrial-triggered ventricular rhythm.
polythene. The electrode tip is a cylin drical platinum knob, 10 mm. long and 3 mm. in diameter (Fig. 1). The "detector" electrode, like the stimulating electrodes, is connected to a specially constructed ap paratus for atrial-triggered pacemaker treat ment. For preliminary evaluation of the thera peutic results as well as the scientific pur poses, we used a commercial apparatus for heart resuscitation manufactured by Corbin Farnsworth, Inc., Palo Alto, Calif. After certain modifications, the pacemaker unit of this apparatus was able to give impulses synchronously with the P wave. The possi bility also exists of varying the conduction time and blocking time. For permanent treat ment, an tmplantable atrial-triggered pace
maker has newly been designed in collabora tion with the Elema-Schönander Co., Stock holm, Sweden. Method. After the patient has been pro vided with conventional intracardiac and indifferent electrodes, and these have been connected to a pacemaker with fixed fre quency, the indications for atrial-triggered pacemaker treatment are considered. If such indications exist, the "detector" electrode is placed on the atrium by means of mediastinoscopy.ir' Under intubation anesthesia and after administration of a muscular re laxant, a small incision is made in the jugular fossa and one dissects along the trachea. Through the mediastinoscope, dis section is continued, under visual control, past the point of bifurcation of the trachea
Journal of
2 32
Carlens et al.
Thoracic and Cardiovascular Surgery
and the right branch of the pulmonary ar tery, to reach the thin layer of connective tissue between the posterior wall of the atrium and the esophagus. When this region has been localized, the electrode tip is ad vanced and placed, with the aid of a forceps, in the connective tissue, as close as possible to the atrial wall, while the amplitude of the P wave is checked on the electrocardio gram. The mediastinoscope is then removed, and the electrode cable is drawn down subcutaneously, with the help of a long injec tion needle, over the chest and abdomen to the right groin. The incision in the neck is then closed. This intervention, with which we now have considerable experience, places extremely little strain on the patient, who can become ambulant on the same day. The "detector" electrode placed in this way is firmly anchored (Fig. 2 ) . The risk of infection is eliminated by the long sub cutaneous tunnel. The P wave, led off be tween the "detector" electrode and the in different electrode, is of the magnitude of at least 1.5 mv., and remains stable (Fig. 3 ) . In this type of transmission, the size of the P wave suffices for regular triggering of the unit which in turn gives impulses to the ventricular electrode (Fig. 4 ) . The con figuration of the P wave is unaffected by movements of the body, swallowing, and the respiratory excursions. With this method one can either connect the electrodes to an external apparatus or sever them where they lie sterile in the subcutaneous tissue, and provide the patient with a pacemaker implanted in this site.
2
3
4
5
6
7
8
9
10
11
12
Summary
13
A method is described for application of electrodes to an atrial-triggered pacemaker without thoracotomy. An account will be given later of the indications, therapeutic results, and hemodynamics as well as an ac count of the new implantable pacemaker.
14
REFERENCES 1 Landegren, J., and Biörck, G.: The Clinical Assessement and Treatment of Complete
15
Heart Block and Adams-Stokes Attacks, Medi cine 42: 171, 1963. Diamond, E. G., Bay, E. B., Chardack, W. M., Dack, S., and Zoll, P. M.: Heart Block: Mech anism and Management, Dis. Chest 43: 456, 1963. Chardack, W. M., Gage, A. A., Federico, A. J., Schimert, G., and Greatbatch, W.: Clinical Experience With an Implantable Pacemaker, Ann. New York Acad. Sc. I l l : 1075, 1964. Zoll, P. M., Frank, H. A., and Linenthal, A. J.: Implantable Cardiac Pacemakers, Ann. New York Acad. Sc. I l l : 1068, 1964. Kantrowitz, A.: Implantable Cardiac Pace makers, Ann. New York Acad. Sc. I l l : 1049, 1964. Elmqvist, R., Landegren, J., Pettersson, S. O., Senning, Â., and William-Olsson, G.: Artificial Pacemaker for Treatment of Adams-Stokes Syndrome and Slow Heart Rate, Am. Heart J. 65: 731, 1963. Widman, W. D., Glenn, W. W. L., Eisenberg, L., and Mauro, A.: Radiofrequency Cardiac Pacemakers, Ann. New York Acad. Sc. I l l : 992, 1964. Norman, J. C , Lightwood, R., and Abrams, L. D.: Surgical Treatment of Adams-Stokes Syndrome Using Long-Term Inductive Cou pled Coil Pacemaking, Ann. Surg. 159: 344, 1964. Cammilli, L., Pozzi, R., and Drago, G.: Re mote Heart Stimulation by Radio Frequency for Permanent Rhythm Control in the Morgagni-Adams-Stokes Syndrome, Surgery 52: 765, 1962. Schwedel, J., and Escher, O. J. W.: Transvenous Electrical Stimulation of the Heart, Ann. New York Acad. Sc. I l l : 972, 1964. Lagergren, H., and Johansson, L.: Intracardiac Stimulation for Complete Heart Block, Acta Chir. Scand. 125: 562, 1963. Parsonnet, W., Zucher, I. R., Gilbert, L., and Meyers, G. H.: A Review of Intracardiac Pacing With Specific Reference to the Use of a Dipolar Electrode, Progr. Cardiovas. Dis. 6: 472, 1964. Nathan, D . A., Center, S., Samet, P., Yu Wu, C , and Keller, J. W., Jr.: The Applica tion of an Implantable Synchronous Pacer for the Correction of Stokes-Adams Attacks, Ann. New York Acad. Sc. I l l : 1093, 1964. Rodewald, G., Giebel, H., Harms, H., and Scheppokat, K. D.: Intravenös-intracardiale Applikation von vorhofsgesteuerten elektris chen Schrittmachern, Ztschr. Kreislaufforsch. 53: 860, 1964. Carlens, E.: Mediastinoscopy: A New Method for Inspection and Tissue Biopsy in the Su perior Mediastinum, Dis. Chest 36: 343, 1959.