- Email: [email protected]
Surgeons, nonsurgeons, and cardiac pacing
1216
CORRESPONDENCE
Reply To the Editor: The letters of Dr Berger and Dr Garibaldi concerning the article by Fleisher and co-workers [1] point out the interest paid by surgeons to the technical issues raised by iatrogenic injury of the coronary sinus and lead me to add two brief comments. I completely agree with Dr Berger that it is safe to "tailor" the degree of balloon inflation to the individual patient's coronary sinus anatomy. It is a matter of daily experience that the volume of fluid required to achieve proper sealing of the coronary sinus varies in relation with the size of the sinus as well as with the precise location of the balloon within the venous conduit. Furthermore, with the use of continuous retrograde cardioplegia, whether cold or warm, this "optimal" inflation volume may vary even in the same patient during the procedure. Thus, every surgeon has experienced that retraction of the heart required for performing a distal obtuse marginal or posterior descending coronary artery anastomosis causes, by itself, a rise in coronary sinus pressure if cardioplegia is being delivered retrogradely. It is therefore my practice to keep the balloon completely deflated (or at most minimally inflated) during this stage of the procedure so that the distal pressure does not exceed, say, 50 mm Hg. As the heart subsequently is repositioned in the pericardial cavity and the operation proceeds with anterior distal anastomoses or associated valve replacement, the pressure obviously goes down and the balloon then is (relinflated until a satisfactory driving pressure is reestablished. Conversely, although I also agree with most of Dr Garibaldi's statements, I cannot share his opinion that "a patch repair probably is conducive to further bleeding or to thrombosis of the coronary sinus." Doctor Fleisher's experience-and that (often unpublished) of others-clearly demonstrates that suture of a large pericardial patch over the area of injury can be, in some instances, the only life-saving technique. I acknowledge, however, that anchoring of the patch may result in some impediment to the venous return, thereby causing an increase in coronary sinus pressure proximal to the obstruction and, consequently, persistent bleeding. Should that occur, the decompression of the area under tension can be accomplished successfully by the interposition of a prosthetic graft between the patch and the right atrium [2]. Philippe Menasche, MD, PhD Department of Cardiovascular Surgery HiJpital Lariboisiere 2 Rue Ambroise Pare 75475 Paris Cedex 10 France
References 1. Fleisher AG, Sarabu MR, Reed GE. Repair of coronary sinus rupture secondary to retrograde cardioplegia. Ann Thorac Surg
1994;57:476-8. 2. Weiss S]. Management of difficult coronary sinus rupture. Ann Thorac Surg 1994;58:548-50.
Surgeons, Nonsurgeons, and Cardiac Pacing
To the Editor: The provocative study by Ferguson and associates [1] entitled "Should Surgeons Still be Implanting Pacemakers?" is commendable but misdirected. I suggest that the correct title should have been "Should Nonsurgeons Implant Pacemakers?" Ferguson and associates invoke the argument of a potential reduction in cost to encourage physicians without primary surgical training to implant permanent pacemakers, emphasizing the po© 1994 by The Society of Thoracic Surgeons
Ann Thorae Surg 1994;58:1212-8
tential reduction in cost. They do not, however, address the skills that well-trained cardiologists and surgeons bring to the implantation facility. An evaluation of the skills, knowledge, and experience listed below may help the reader to appreciate how specialized and exquisite pacemaker implantation has become. As a surgeon responsible for training residents and fellows, experience has taught me the limitations of the technical capabilities of house officers and most attending nonsurgeons in the operating room. Some trainees fumble through knot-tying for months; some never learn. (There are a few exceptions to this unkindly generalization about surgical skills; a co-author of the article is one of them.) In the face of unusual situations such as the absence of veins, scarring at the operative site, and anatomic variations, the nonsurgeon often is lost. Some hardly can learn how to expose the cephalic vein, an operative approach that has gained new importance in light of the dangers of introducerrelated complications; tension pneumothorax, hemothorax, wound hemorrhage, and lead-conductor crush fracture between the first rib and the clavicle are just a few of these unfortunate events. Nonsurgeons now are embarking on solo insertion of implanted cardioverter / defibrillators. Imagine the problems that soon will appear with the unbridled proliferation of this practice! Outsiders tend to regard pacemaker implantation as a minor procedure, one that can be learned easily by anyone. As an example of this attitude, some pacemaker manufacturers for years have sent their nonsurgeon customers to a week's "training" in Europe, after which they return as "certified" pacemaker experts. Rumors have it that this disgraceful practice still exists. I still receive requests from nonsurgeons for permission to watch me do a case or two; the supposition is that they will thereby learn all there is to know about pacing and they will then return home to do the work themselves. Recommendations for appropriate training have not been lacking; several publications have enunciated them [2-7]. It is abundantly clear that the subspecialty of pacing is complex and requires substantial preparation; it cannot be treated lightly. The following list, although not comprehensive, illustrates the scope of these topics, which fall roughly into three categories: I. Clinical assessment of the patient; selection of therapy and devices 1. Clinical characteristics that distinguish cardiac from noncardiac syncope; interpretation of ambulatory-monitoring reports and event recordings, exercise testing, electrophysiologic testing, tilt-table testing, carotid-sinus massage, Valsalva and Muller maneuvers; physical examination including cardiac auscultation and a search for other causes of syncope; knowledge of cardiac anatomy, including normal and congenital variations of the venous system, conduction system, cardiac blood supply, and the relationship of the heart to the surrounding tissues; cardiac effects of various drugs, electrolyte disturbances, hypoxia, and systemic and neurologic disease. 2. Selection and prescription of appropriate physiologic pacing modes.
II. Knowledge and skills related to pacemaker insertion 1. Understanding of basic surgical principles including sterile operating-room techniques, skin preparations, and draping; indications and uses of various anesthetics and soporifics; maintenance of airway patency; techniques of incising, ligating, suturing, tissue handling, and hemostasis. 2. Identifying anatomic landmarks, methods of venous cutdown on a variety of access veins, familiarity with the introducer technique, management of intraoperative problems such as vascular lacerations, pneumothorax, massive
0003-4975/94/$7.00
CORRESPONDENCE
Ann Thorae Surg
1217
1994;58:1212-8
air embolization, embolizing guidewire, wound closure, indications for drainage, and management of hemorrhage. 3. Radiographic and fluoroscopic interpretation, including evaluation of cardiac-chamber size and location, valve and annular calcifications, and intracardiac foreign bodies including artificial valves, shunts, and previous pacemaker paraphernalia; recognizing implanted pulse-generator models and specific radiographic signatures; identifying congenital anomalies that relate to lead placement, assessing correct and abnormal atrial and ventricular lead positions, recognizing perforated leads or leads in the coronary sinus, and detecting lead fractures and connector deficiencies. 4. Skills related to elective and emergent temporary transvenous and transthoracic pacing [8]. 5. Familiarity with resources for device-related information and technical assistance. III. Skills related to device management 1. Measuring and interpreting stimulation thresholds, endocardial signal strength and intrinsic-deflection slope, lead impedance, injury currents, intrinsic deflection, refractory periods, supernormal conduction, and ventriculoatrial conduction. 2. Data acquisition, including the use of various pacemakersystems analyzers; computer techniques and automated systems. 3. Interpreting the paced electrocardiogram, including evaluation of the integrity of pacing and sensing; crosstalk and specialized crosstalk-management features, cross-stimulation, polarization-voltage and ectopic-beat responses, pacemaker-mediated tachycardias, myopotential inhibition, electromagnetic interference, backup modes, upper-rate behavior, blanking phenomena, end-of-life indicators, refractory periods, adaptive responses, and other self-regulating features. Recognizing malfunctions and-especiallypseudomalfunctions. Interpreting telemetry data: intracardiac electrograms, lead and battery "impedance," battery voltage, current drain, event counters, and end-oflife characteristics and indicators. 4. Managing connectors and leads; understanding pulsegenerator and lead compatibility. 5. Familiarity with methods of programming and troubleshooting; diagnosing and managing complications, including high stimulation thresholds and marginal sensingsignal characteristics, abnormal electrode positions, pacemaker syndrome, and unusual timing events; familiarity with the tools of follow-up, including programming devices and transtelephonic monitors; discriminating between abnormal and normal functions, recognizing electromagnetic-interference responses and backup modes, and familiarity with a wide variety of adaptive features, including single- and dual-sensor rate modulation, adaptive AV intervals and refractory periods, and adaptive upper-rate behavior, including automatic pacing-mode changes at high spontaneous atrial rates. Although there is an "unofficial" examination of special competence in pacing administered by the North American Society of Pacing and Electrophysiology [9], there still is no mechanism for "official" certification of pacemaker implanters [10], and the referenced sensible and well-thought-out guidelines are largely ignored. Some hospitals have guidelines for their own practitioners, but it is not common. In the United States, most permanent pacemakers are inserted by infrequent implanters (averaging fewer than 11 implantations per year), who almost always rely on
manufacturers' sales representatives to coach them through the procedure and perform the requisite threshold measurements [11]. Along the same lines, more than one-third of the pacemaker pulse generators implanted in the United States are never reprogrammed after implantation but left with the default settings as shipped by the manufacturer [11]. Failure to adjust the stimulus amplitude and duration appropriately can reduce the battery's life expectancy by as much as 50%, effectively adding to the cost of pacing. Even worse, failure to program the device appropriately wastes the enormous adaptability of modern dual-chamber pacemakers. There is strong evidence to prove that incorrect pacing modes not only are unphysiologic but also increase the incidence of atrial fibrillation and decrease the patient's life expectancy [12]. For these reasons (and many others), it should have been argued that pacemaker and implantable cardioverter / defibrillator implantation should be performed only by physicians trained in the field. Not only should the work be performed in a "center of excellence," as wisely recommended by Ferguson and associates, but by "physicians of excellence," surgeons or nonsurgeons, with the training, qualifications, and certification (will it ever happen?) necessary to do the work safely and effectively. Victor Parsonnet, MO Newark Beth Israel Medical Center 201 Lyons Ave Newark, NJ 07112 References
1. Ferguson TB [r, Lindsay BD, Boineau JP. Should surgeons still be implanting pacemakers? Ann Thorac Surg 1994;57:588-97. 2. Resources required for pacemaker implantation. NASPE policy-conference report. PACE 1983;6:139-55. 3. Optimal resources for implantable cardiac pacemakers. Report of the Inter-Society Commission for Heart Disease Resources. Circulation 1993;68:227A-44A. 4. 17th Bethesda Conference, Task Force VI: training in cardiac pacing. J Am Coli Cardiol 1986;7:1213-4. 5. ACC/ AHA Task Force Report: Guidelines for implantation of cardiac pacemakers and antiarrhythmia devices. J Am Coli Cardiol 1991;18:1-13. 6. Report of the NASPE policy conference training requirements for permanent pacemaker selection, implantation, and followup. PACE 1994;17:6-12. 7. Antibradycardia-pacemaker follow-up: effectiveness, needs, and resources. NASPE policy-conference report. PACE (in press). 8. Francis GS, Williams SV, Achord JL, et al. Clinical competence in insertion of a temporary transvenous ventricular pacemaker. Circulation 1994;89:1913-6. 9. Furman S, Bilitch M. NASPExAM. PACE 1987;10:278-80. 10. Gillette P. Special certification in cardiac pacing. PACE 1991; 14:141-2. 11. Bernstein AD, Parsonnet V. Survey of cardiac pacing practices in the United States in 1989. Am J Cardiol 1992;69:331-8. 12. Mahoney CB. Patient outcomes and cost considerations: comparing pacing modes via meta-analysis. Medtronic News 1994;22:4-11.
Reply To the Editor:
We appreciate the comments of Dr Parsonnet, and acknowledge his long-standing interest in the problem outlined in our article [I] and in his letter. As outlined in his letter, we are in general agreement with the recommendations for training of implanters of pacemakers. However, the circumstances for actually training individuals to meet
CORRESPONDENCE
Reply To the Editor: The letters of Dr Berger and Dr Garibaldi concerning the article by Fleisher and co-workers [1] point out the interest paid by surgeons to the technical issues raised by iatrogenic injury of the coronary sinus and lead me to add two brief comments. I completely agree with Dr Berger that it is safe to "tailor" the degree of balloon inflation to the individual patient's coronary sinus anatomy. It is a matter of daily experience that the volume of fluid required to achieve proper sealing of the coronary sinus varies in relation with the size of the sinus as well as with the precise location of the balloon within the venous conduit. Furthermore, with the use of continuous retrograde cardioplegia, whether cold or warm, this "optimal" inflation volume may vary even in the same patient during the procedure. Thus, every surgeon has experienced that retraction of the heart required for performing a distal obtuse marginal or posterior descending coronary artery anastomosis causes, by itself, a rise in coronary sinus pressure if cardioplegia is being delivered retrogradely. It is therefore my practice to keep the balloon completely deflated (or at most minimally inflated) during this stage of the procedure so that the distal pressure does not exceed, say, 50 mm Hg. As the heart subsequently is repositioned in the pericardial cavity and the operation proceeds with anterior distal anastomoses or associated valve replacement, the pressure obviously goes down and the balloon then is (relinflated until a satisfactory driving pressure is reestablished. Conversely, although I also agree with most of Dr Garibaldi's statements, I cannot share his opinion that "a patch repair probably is conducive to further bleeding or to thrombosis of the coronary sinus." Doctor Fleisher's experience-and that (often unpublished) of others-clearly demonstrates that suture of a large pericardial patch over the area of injury can be, in some instances, the only life-saving technique. I acknowledge, however, that anchoring of the patch may result in some impediment to the venous return, thereby causing an increase in coronary sinus pressure proximal to the obstruction and, consequently, persistent bleeding. Should that occur, the decompression of the area under tension can be accomplished successfully by the interposition of a prosthetic graft between the patch and the right atrium [2]. Philippe Menasche, MD, PhD Department of Cardiovascular Surgery HiJpital Lariboisiere 2 Rue Ambroise Pare 75475 Paris Cedex 10 France
References 1. Fleisher AG, Sarabu MR, Reed GE. Repair of coronary sinus rupture secondary to retrograde cardioplegia. Ann Thorac Surg
1994;57:476-8. 2. Weiss S]. Management of difficult coronary sinus rupture. Ann Thorac Surg 1994;58:548-50.
Surgeons, Nonsurgeons, and Cardiac Pacing
To the Editor: The provocative study by Ferguson and associates [1] entitled "Should Surgeons Still be Implanting Pacemakers?" is commendable but misdirected. I suggest that the correct title should have been "Should Nonsurgeons Implant Pacemakers?" Ferguson and associates invoke the argument of a potential reduction in cost to encourage physicians without primary surgical training to implant permanent pacemakers, emphasizing the po© 1994 by The Society of Thoracic Surgeons
Ann Thorae Surg 1994;58:1212-8
tential reduction in cost. They do not, however, address the skills that well-trained cardiologists and surgeons bring to the implantation facility. An evaluation of the skills, knowledge, and experience listed below may help the reader to appreciate how specialized and exquisite pacemaker implantation has become. As a surgeon responsible for training residents and fellows, experience has taught me the limitations of the technical capabilities of house officers and most attending nonsurgeons in the operating room. Some trainees fumble through knot-tying for months; some never learn. (There are a few exceptions to this unkindly generalization about surgical skills; a co-author of the article is one of them.) In the face of unusual situations such as the absence of veins, scarring at the operative site, and anatomic variations, the nonsurgeon often is lost. Some hardly can learn how to expose the cephalic vein, an operative approach that has gained new importance in light of the dangers of introducerrelated complications; tension pneumothorax, hemothorax, wound hemorrhage, and lead-conductor crush fracture between the first rib and the clavicle are just a few of these unfortunate events. Nonsurgeons now are embarking on solo insertion of implanted cardioverter / defibrillators. Imagine the problems that soon will appear with the unbridled proliferation of this practice! Outsiders tend to regard pacemaker implantation as a minor procedure, one that can be learned easily by anyone. As an example of this attitude, some pacemaker manufacturers for years have sent their nonsurgeon customers to a week's "training" in Europe, after which they return as "certified" pacemaker experts. Rumors have it that this disgraceful practice still exists. I still receive requests from nonsurgeons for permission to watch me do a case or two; the supposition is that they will thereby learn all there is to know about pacing and they will then return home to do the work themselves. Recommendations for appropriate training have not been lacking; several publications have enunciated them [2-7]. It is abundantly clear that the subspecialty of pacing is complex and requires substantial preparation; it cannot be treated lightly. The following list, although not comprehensive, illustrates the scope of these topics, which fall roughly into three categories: I. Clinical assessment of the patient; selection of therapy and devices 1. Clinical characteristics that distinguish cardiac from noncardiac syncope; interpretation of ambulatory-monitoring reports and event recordings, exercise testing, electrophysiologic testing, tilt-table testing, carotid-sinus massage, Valsalva and Muller maneuvers; physical examination including cardiac auscultation and a search for other causes of syncope; knowledge of cardiac anatomy, including normal and congenital variations of the venous system, conduction system, cardiac blood supply, and the relationship of the heart to the surrounding tissues; cardiac effects of various drugs, electrolyte disturbances, hypoxia, and systemic and neurologic disease. 2. Selection and prescription of appropriate physiologic pacing modes.
II. Knowledge and skills related to pacemaker insertion 1. Understanding of basic surgical principles including sterile operating-room techniques, skin preparations, and draping; indications and uses of various anesthetics and soporifics; maintenance of airway patency; techniques of incising, ligating, suturing, tissue handling, and hemostasis. 2. Identifying anatomic landmarks, methods of venous cutdown on a variety of access veins, familiarity with the introducer technique, management of intraoperative problems such as vascular lacerations, pneumothorax, massive
0003-4975/94/$7.00
CORRESPONDENCE
Ann Thorae Surg
1217
1994;58:1212-8
air embolization, embolizing guidewire, wound closure, indications for drainage, and management of hemorrhage. 3. Radiographic and fluoroscopic interpretation, including evaluation of cardiac-chamber size and location, valve and annular calcifications, and intracardiac foreign bodies including artificial valves, shunts, and previous pacemaker paraphernalia; recognizing implanted pulse-generator models and specific radiographic signatures; identifying congenital anomalies that relate to lead placement, assessing correct and abnormal atrial and ventricular lead positions, recognizing perforated leads or leads in the coronary sinus, and detecting lead fractures and connector deficiencies. 4. Skills related to elective and emergent temporary transvenous and transthoracic pacing [8]. 5. Familiarity with resources for device-related information and technical assistance. III. Skills related to device management 1. Measuring and interpreting stimulation thresholds, endocardial signal strength and intrinsic-deflection slope, lead impedance, injury currents, intrinsic deflection, refractory periods, supernormal conduction, and ventriculoatrial conduction. 2. Data acquisition, including the use of various pacemakersystems analyzers; computer techniques and automated systems. 3. Interpreting the paced electrocardiogram, including evaluation of the integrity of pacing and sensing; crosstalk and specialized crosstalk-management features, cross-stimulation, polarization-voltage and ectopic-beat responses, pacemaker-mediated tachycardias, myopotential inhibition, electromagnetic interference, backup modes, upper-rate behavior, blanking phenomena, end-of-life indicators, refractory periods, adaptive responses, and other self-regulating features. Recognizing malfunctions and-especiallypseudomalfunctions. Interpreting telemetry data: intracardiac electrograms, lead and battery "impedance," battery voltage, current drain, event counters, and end-oflife characteristics and indicators. 4. Managing connectors and leads; understanding pulsegenerator and lead compatibility. 5. Familiarity with methods of programming and troubleshooting; diagnosing and managing complications, including high stimulation thresholds and marginal sensingsignal characteristics, abnormal electrode positions, pacemaker syndrome, and unusual timing events; familiarity with the tools of follow-up, including programming devices and transtelephonic monitors; discriminating between abnormal and normal functions, recognizing electromagnetic-interference responses and backup modes, and familiarity with a wide variety of adaptive features, including single- and dual-sensor rate modulation, adaptive AV intervals and refractory periods, and adaptive upper-rate behavior, including automatic pacing-mode changes at high spontaneous atrial rates. Although there is an "unofficial" examination of special competence in pacing administered by the North American Society of Pacing and Electrophysiology [9], there still is no mechanism for "official" certification of pacemaker implanters [10], and the referenced sensible and well-thought-out guidelines are largely ignored. Some hospitals have guidelines for their own practitioners, but it is not common. In the United States, most permanent pacemakers are inserted by infrequent implanters (averaging fewer than 11 implantations per year), who almost always rely on
manufacturers' sales representatives to coach them through the procedure and perform the requisite threshold measurements [11]. Along the same lines, more than one-third of the pacemaker pulse generators implanted in the United States are never reprogrammed after implantation but left with the default settings as shipped by the manufacturer [11]. Failure to adjust the stimulus amplitude and duration appropriately can reduce the battery's life expectancy by as much as 50%, effectively adding to the cost of pacing. Even worse, failure to program the device appropriately wastes the enormous adaptability of modern dual-chamber pacemakers. There is strong evidence to prove that incorrect pacing modes not only are unphysiologic but also increase the incidence of atrial fibrillation and decrease the patient's life expectancy [12]. For these reasons (and many others), it should have been argued that pacemaker and implantable cardioverter / defibrillator implantation should be performed only by physicians trained in the field. Not only should the work be performed in a "center of excellence," as wisely recommended by Ferguson and associates, but by "physicians of excellence," surgeons or nonsurgeons, with the training, qualifications, and certification (will it ever happen?) necessary to do the work safely and effectively. Victor Parsonnet, MO Newark Beth Israel Medical Center 201 Lyons Ave Newark, NJ 07112 References
1. Ferguson TB [r, Lindsay BD, Boineau JP. Should surgeons still be implanting pacemakers? Ann Thorac Surg 1994;57:588-97. 2. Resources required for pacemaker implantation. NASPE policy-conference report. PACE 1983;6:139-55. 3. Optimal resources for implantable cardiac pacemakers. Report of the Inter-Society Commission for Heart Disease Resources. Circulation 1993;68:227A-44A. 4. 17th Bethesda Conference, Task Force VI: training in cardiac pacing. J Am Coli Cardiol 1986;7:1213-4. 5. ACC/ AHA Task Force Report: Guidelines for implantation of cardiac pacemakers and antiarrhythmia devices. J Am Coli Cardiol 1991;18:1-13. 6. Report of the NASPE policy conference training requirements for permanent pacemaker selection, implantation, and followup. PACE 1994;17:6-12. 7. Antibradycardia-pacemaker follow-up: effectiveness, needs, and resources. NASPE policy-conference report. PACE (in press). 8. Francis GS, Williams SV, Achord JL, et al. Clinical competence in insertion of a temporary transvenous ventricular pacemaker. Circulation 1994;89:1913-6. 9. Furman S, Bilitch M. NASPExAM. PACE 1987;10:278-80. 10. Gillette P. Special certification in cardiac pacing. PACE 1991; 14:141-2. 11. Bernstein AD, Parsonnet V. Survey of cardiac pacing practices in the United States in 1989. Am J Cardiol 1992;69:331-8. 12. Mahoney CB. Patient outcomes and cost considerations: comparing pacing modes via meta-analysis. Medtronic News 1994;22:4-11.
Reply To the Editor:
We appreciate the comments of Dr Parsonnet, and acknowledge his long-standing interest in the problem outlined in our article [I] and in his letter. As outlined in his letter, we are in general agreement with the recommendations for training of implanters of pacemakers. However, the circumstances for actually training individuals to meet