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Permanent Cardiac Pacemakers in Children: Technical Considerations
Permanent Cardiac Pacemakers in Children: Technical Considerations James S. Donahoo, M.D., J. Alex Haller, M.D., Steven Zonnebelt, B.S., Catherine Neill, M.D., Vincent L. Gott, M.D., and Robert K. Brawley, M.D. ABSTRACT Placement of permanent cardiac pacemakers in children presents technical problems that are not encountered in the adult. Problems unique to pacemaker implantation in children are related to the patient's size, the relative bulkiness of pulse generators, the lack of subcutaneous tissue, and the child's growth and long life expectancy. Based on our experience with implantation of 27 permanent cardiac pacemakers in 13 children, we have found that the use of small pulse generators, placement of epicardial leads, insertion of properitoneal pulse generators, and use of rechargeable pacemakers are satisfactory methods in children.
Although extensive experience with the use of permanent implantable pacemakers in adults has accumulated, relatively few reports have been published on permanent pacer implantation in infants and children [2-4, 7, 81 and very little late follow-up information is available on these patients. While heart block in children is an unusual occurrence, the placement of a permanent pacemaker in a young infant or child is associated with many technical problems not encountered in the adult population. In an attempt to delineate these problems and to offer methods for dealing with them, we have reviewed the children at our institution in whom permanent implantable pacemakers have been inserted. Clinical Material and Results From 1960 through 1974, 27 permanent pacemakers were implanted in 13 children at The From the Departments of Surgery and Pediatrics, The Johns Hopkins University School of Medicine, Baltimore, MD. Presented at the Twenty-second Annual Meeting of the SouthernThoracic Surgical Association, Nov 633,1975, New Orleans, LA. Address reprint requests to Dr. Donahoo, Department of Surgery, The Johns Hopkins Hospital, Baltimore, MD 21205.
584
Johns Hopkins Hospital. The ages of the patients at the time of initial pacemaker implantation ranged from 36 hours to 17 years with an average of 6.8 years. The indication for pacemaker implantation was surgically induced heart block in 11 patients and congenital heart block in 2. The results of pacemaker implantation in the patients with surgical heart block are reflected in 2 deaths, both unrelated to the pacemaker. The 2 patients in whom congenital heart block was the indication for pacemaker implantation died, 1of congestive heart failure 36 hours postoperatively and the other from myocardiopathy one year after pacemaker implantation. There is late follow-up on the survivors with surgical heart block. The average follow-up is 5 years, ranging from 13 months to 12 years. In 6, the pacemakers remain in place. However, pacemakers have been removed in 2 patients; both are doing well presently, and 1is in sinus rhythm. The remaining 6 patients are having no serious problems related to their pacemaker. Comment Implantation of a permanent pacemaker in a child, especially a young child, results in tremendous morbidity. Although there have been no deaths or serious complications related to long-term pacing in the children in this series, considerable expense and anxiety are involved in the management of children with permanent pacemakers. Our review of children with permanent pulse generator implantation showed a number of problems that are common in trying to implant pacemakers in infants and children. Most fall into the technical area because of the size of the patient and his potential growth. Most transvenous electrodes are too large to be placed in the veins of infants and small children, and this necessitates implantation of epicardial pacemaker leads. Although in older
585
Donahoo et al: Permanent Cardiac Pacemakers in Children
children the transdiaphragmatic approach obviates the need for a thoracic incision, we have preferred the transthoracic approach illustrated in Figure 1.We have been somewhat reluctant to utilize the diaphragmatic surface of the heart and the thin-walled right ventricle for attaching epicardial leads in younger children. The transthoracic approach enables us to get better visualization of the surface of the left ventricle, the preferred insertion site because of its thicker wall. The size of the pulse generator may present problems in very small children. The necessity for using a smaller pacemaker limits the varieties that can be implanted. We have experience with the Medtronic Model 5855 unipolar asynchronous pacemaker. This unit is somewhat smaller than the adult type, but its fixed rate can Fig 1 . Technique of transthoracic epicardial lead placement. T h e thicker-walled left ventricle is preferred for lead insertion.
be disadvantageous since it precludes response to exercise or stress factors. This unit is shaped rather like a yo-yo, with a circumferential groove around it. The groove is useful since the lead wire can be wrapped in it and then unlooped as the child grows. This growth of the child represents another problem. The length of the pacemaker leads must be taken into account and an extra length left inside the pacemaker pocket. Because of the marked lack of subcutaneous tissue in infants and young children and the relative bulkiness of current pulse generators, we have used the technique of properitoneal implantation of the pulse generator through a muscle-splitting incision in the abdomen (Fig 2). This approach lessens the problem of erosion over the pulse generator and is more cosmetically pleasing to the patient. Despite the theoretical disadvantage of migration of the pulse generator in the properitoneal area, we have not noticed this problem. Pulse generator changes after
8C.
a.
586 The Annals of Thoracic Surgery Vol 22 No 6 December 1976
Section Fig2. The technique of properitoneal implantation of a permanent pacemaker pulsegenerator. The pulse generator can also be placed below the rectus abdominis muscle.
properitoneal implantation have entailed no special difficulty. A pseudomembrane surrounds the pulse generator, and it is as easy to change this pacemaker as one placed in the subcutaneous position. The frequency of pulse generator replacement can be extremely problematic in childhood. Whereas the average age for pacemaker implantation in adults is greater than 60 years, in our patients it was 6.8 years, representing the need for a large number of pacemaker changes in the future. The use of a rechargeable pacemaker* *Pacesetter Systems, Inc, Sylmar, CA.
with a projected life expectancy of 10 to 20 years may be helpful. The rechargeable pacemaker has been in clinical use since 1971 without apparent difficulties [l, 5, 61 and has many features that are advantageous for use in children. The pacemaker has a rechargeable nickel cadmium battery and is relatively small. Recharging is done by placing an induction coil on the skin overlying the pulse generator for one hour per week. The method is simple and almost foolproof. The rechargeable pacemaker has been implanted in a number of children throughout the United States, and each unit appears to be working satisfactorily. Dr. Kenneth Lewis reports that 81 rechargeable pacemakers have been implanted in children ranging from neonates to 10 years of age and an additional 83 units in patients 11to 20 years old, representing a total of 164 units placed in pa-
587 Donahoo et al: Permanent Cardiac Pacemakers in Children
tients u n d e r 20 years of age out of 3,320 rechargeable pacemakers implanted altogether.* W e have implanted this rechargeable pacemaker in 3 patients a t The Johns Hopkins Hospital a n d have experienced n o problems w i t h its use
4.
5.
References 1. Barnhart PW, Fischell RE, Lewis KB, et al: A fixed rate rechargeable cardiac pacemaker. Appl Physics Lab Techn Dig 9:2, 1970 2. Glenn WW, de Leuchtenberg N, van Heeckeren DW, et al: Heart block in children: treatment with a radiofrequency pacemaker. J Thorac Cardiovasc Surg 58:361, 1969 3. Harris PD, Bowman FO, Griffiths SP: Implantation *Lewis K: Personal communication, 1976.
6. 7.
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of a synchronous pacing unit in a seven-month-old infant. J Thorac Cardiovasc Surg 52:277, 1966 Idriss FS, Otto R, Nikaidoh H, et al: Implantation of permanent pacemaker in the first month of life for congenital complete heart block. J Thorac Cardiovasc Surg 652351, 1973 Lewis KB, Fischell RG, Love JW: A permanent rechargeable cardiac pacemaker. Circulation 4O:Suppl3:132, 1969 LoveJW, Lewis KB, Fischell RE, et al: Experimental testing of a permanent rechargeable cardiac pacemaker. Ann Thorac Surg 17:152, 1974 Martin M V , Lime AB, Almeida CS, et al: Implantation of Chardack Greatbatch adjustable rate and current pacemaker in a four-month-old infant. Pediatrics 37:323, 1966 Trusler GA, Mustard WT, Keith JD: The role of pacemaker therapy in congenital heart block: report of three cases. J Thorac Cardiovasc Surg 55:105, 1968
Although extensive experience with the use of permanent implantable pacemakers in adults has accumulated, relatively few reports have been published on permanent pacer implantation in infants and children [2-4, 7, 81 and very little late follow-up information is available on these patients. While heart block in children is an unusual occurrence, the placement of a permanent pacemaker in a young infant or child is associated with many technical problems not encountered in the adult population. In an attempt to delineate these problems and to offer methods for dealing with them, we have reviewed the children at our institution in whom permanent implantable pacemakers have been inserted. Clinical Material and Results From 1960 through 1974, 27 permanent pacemakers were implanted in 13 children at The From the Departments of Surgery and Pediatrics, The Johns Hopkins University School of Medicine, Baltimore, MD. Presented at the Twenty-second Annual Meeting of the SouthernThoracic Surgical Association, Nov 633,1975, New Orleans, LA. Address reprint requests to Dr. Donahoo, Department of Surgery, The Johns Hopkins Hospital, Baltimore, MD 21205.
584
Johns Hopkins Hospital. The ages of the patients at the time of initial pacemaker implantation ranged from 36 hours to 17 years with an average of 6.8 years. The indication for pacemaker implantation was surgically induced heart block in 11 patients and congenital heart block in 2. The results of pacemaker implantation in the patients with surgical heart block are reflected in 2 deaths, both unrelated to the pacemaker. The 2 patients in whom congenital heart block was the indication for pacemaker implantation died, 1of congestive heart failure 36 hours postoperatively and the other from myocardiopathy one year after pacemaker implantation. There is late follow-up on the survivors with surgical heart block. The average follow-up is 5 years, ranging from 13 months to 12 years. In 6, the pacemakers remain in place. However, pacemakers have been removed in 2 patients; both are doing well presently, and 1is in sinus rhythm. The remaining 6 patients are having no serious problems related to their pacemaker. Comment Implantation of a permanent pacemaker in a child, especially a young child, results in tremendous morbidity. Although there have been no deaths or serious complications related to long-term pacing in the children in this series, considerable expense and anxiety are involved in the management of children with permanent pacemakers. Our review of children with permanent pulse generator implantation showed a number of problems that are common in trying to implant pacemakers in infants and children. Most fall into the technical area because of the size of the patient and his potential growth. Most transvenous electrodes are too large to be placed in the veins of infants and small children, and this necessitates implantation of epicardial pacemaker leads. Although in older
585
Donahoo et al: Permanent Cardiac Pacemakers in Children
children the transdiaphragmatic approach obviates the need for a thoracic incision, we have preferred the transthoracic approach illustrated in Figure 1.We have been somewhat reluctant to utilize the diaphragmatic surface of the heart and the thin-walled right ventricle for attaching epicardial leads in younger children. The transthoracic approach enables us to get better visualization of the surface of the left ventricle, the preferred insertion site because of its thicker wall. The size of the pulse generator may present problems in very small children. The necessity for using a smaller pacemaker limits the varieties that can be implanted. We have experience with the Medtronic Model 5855 unipolar asynchronous pacemaker. This unit is somewhat smaller than the adult type, but its fixed rate can Fig 1 . Technique of transthoracic epicardial lead placement. T h e thicker-walled left ventricle is preferred for lead insertion.
be disadvantageous since it precludes response to exercise or stress factors. This unit is shaped rather like a yo-yo, with a circumferential groove around it. The groove is useful since the lead wire can be wrapped in it and then unlooped as the child grows. This growth of the child represents another problem. The length of the pacemaker leads must be taken into account and an extra length left inside the pacemaker pocket. Because of the marked lack of subcutaneous tissue in infants and young children and the relative bulkiness of current pulse generators, we have used the technique of properitoneal implantation of the pulse generator through a muscle-splitting incision in the abdomen (Fig 2). This approach lessens the problem of erosion over the pulse generator and is more cosmetically pleasing to the patient. Despite the theoretical disadvantage of migration of the pulse generator in the properitoneal area, we have not noticed this problem. Pulse generator changes after
8C.
a.
586 The Annals of Thoracic Surgery Vol 22 No 6 December 1976
Section Fig2. The technique of properitoneal implantation of a permanent pacemaker pulsegenerator. The pulse generator can also be placed below the rectus abdominis muscle.
properitoneal implantation have entailed no special difficulty. A pseudomembrane surrounds the pulse generator, and it is as easy to change this pacemaker as one placed in the subcutaneous position. The frequency of pulse generator replacement can be extremely problematic in childhood. Whereas the average age for pacemaker implantation in adults is greater than 60 years, in our patients it was 6.8 years, representing the need for a large number of pacemaker changes in the future. The use of a rechargeable pacemaker* *Pacesetter Systems, Inc, Sylmar, CA.
with a projected life expectancy of 10 to 20 years may be helpful. The rechargeable pacemaker has been in clinical use since 1971 without apparent difficulties [l, 5, 61 and has many features that are advantageous for use in children. The pacemaker has a rechargeable nickel cadmium battery and is relatively small. Recharging is done by placing an induction coil on the skin overlying the pulse generator for one hour per week. The method is simple and almost foolproof. The rechargeable pacemaker has been implanted in a number of children throughout the United States, and each unit appears to be working satisfactorily. Dr. Kenneth Lewis reports that 81 rechargeable pacemakers have been implanted in children ranging from neonates to 10 years of age and an additional 83 units in patients 11to 20 years old, representing a total of 164 units placed in pa-
587 Donahoo et al: Permanent Cardiac Pacemakers in Children
tients u n d e r 20 years of age out of 3,320 rechargeable pacemakers implanted altogether.* W e have implanted this rechargeable pacemaker in 3 patients a t The Johns Hopkins Hospital a n d have experienced n o problems w i t h its use
4.
5.
References 1. Barnhart PW, Fischell RE, Lewis KB, et al: A fixed rate rechargeable cardiac pacemaker. Appl Physics Lab Techn Dig 9:2, 1970 2. Glenn WW, de Leuchtenberg N, van Heeckeren DW, et al: Heart block in children: treatment with a radiofrequency pacemaker. J Thorac Cardiovasc Surg 58:361, 1969 3. Harris PD, Bowman FO, Griffiths SP: Implantation *Lewis K: Personal communication, 1976.
6. 7.
8.
of a synchronous pacing unit in a seven-month-old infant. J Thorac Cardiovasc Surg 52:277, 1966 Idriss FS, Otto R, Nikaidoh H, et al: Implantation of permanent pacemaker in the first month of life for congenital complete heart block. J Thorac Cardiovasc Surg 652351, 1973 Lewis KB, Fischell RG, Love JW: A permanent rechargeable cardiac pacemaker. Circulation 4O:Suppl3:132, 1969 LoveJW, Lewis KB, Fischell RE, et al: Experimental testing of a permanent rechargeable cardiac pacemaker. Ann Thorac Surg 17:152, 1974 Martin M V , Lime AB, Almeida CS, et al: Implantation of Chardack Greatbatch adjustable rate and current pacemaker in a four-month-old infant. Pediatrics 37:323, 1966 Trusler GA, Mustard WT, Keith JD: The role of pacemaker therapy in congenital heart block: report of three cases. J Thorac Cardiovasc Surg 55:105, 1968