eMedicine Specialties > Pediatrics: Cardiac Disease and Critical Care Medicine > Cardiology
Pacemaker Therapy: Treatment
Updated: Nov 25, 2008
Treatment
Surgical Therapy
Pacemaker Pulse Generators in Children
Size is an important factor in pacemaker selection, particularly for infants and smaller children. Modern generators have markedly reduced mass, width, and circumference, and single-chamber and dual-chamber devices are now similarly sized.
No pacemaker is specifically designed for pediatric use. Each generator has special features and options, which vary among different manufacturers and specific models. Some features may be particularly appropriate or inappropriate for children. For example, because pacemakers are designed primarily for adults, resting heart rate is expected to be less than 100 bpm. Most pacemakers released prior to 1996 had a maximum rate limit of 120-130 bpm, which may be inadequate for a neonate or critically ill postoperative infant.
A programmable lower and upper rate limit may require a higher setting in children to compensate for increased demands on myocardial oxygen consumption, cardiac output response to exercise, and increased predicted maximum heart rates with exertion. Unfortunately, battery longevity is sacrificed in favor of optimizing hemodynamic performance. Because cardiac output is more critically dependent on heart rate in children, the requirement for faster pacing rates increases battery expenditure.
Single versus dual-chamber pacing debate
Experts now debate whether dual-chamber synchronous pacing is superior to single-chamber ventricular pacing. Atrial-based pacing, which includes AAI(R), DDD, and VDD(R) pacing modes, has been shown superior to ventricular-based (VVIR) pacing in studies of adults, although controversy regarding DDD versus VVI pacing continues. Several large-scale prospective studies are underway to help illuminate these issues.
In adult studies, dual-chamber pacing may have lower morbidity and mortality compared with ventricular pacing in patients with congestive heart failure, valvular heart diseases, and hypertensive heart disease. Studies indicate higher incidences of death, stroke, atrial fibrillation, pacemaker syndrome, and heart failure during VVI pacing, compared to DDD pacing modes. An apparently convincing argument advocates atrial-based pacing (either single-chamber AAI(R) or dual-chamber modes) over ventricular-based pacing modalities, although whether DDD is better than AAI(R) for patients with intact atrioventricular conduction is less clear.
Experimental data that address pacing in children are more limited, and some conclusions are extrapolated from adult patient series. Common pacing indications in children are similar to adults (eg, sinus node dysfunction, atrioventricular [AV] node dysfunction), although concomitant cardiac, medical, psychological, and size-related issues often differ markedly. Rate-responsive ventricular pacing often has been used in children with complete AV block. Rate-responsive ventricular pacing also adequately responds to physiological demands of healthy active children.
Many pediatric patients, however, have underlying structural heart disease, tachyarrhythmia, and hemodynamic derangements that compromise ventricular performance. In addition, pediatric patients frequently have structural anatomic barriers to implantation and limited access to cardiac chambers. Many patients with prior atrial surgery (ie, Fontan, Mustard, Senning procedures) have both bradyarrhythmia and tachyarrhythmia. Some studies have demonstrated higher atrial-pacing failure rate in these patients, presumably due to higher atrial pressures, scarring, and ischemia.
A large retrospective series from Boston Children's Hospital revealed no significant differences between many patients who had undergone Fontan or atrial switch surgeries.4 Investigators compared these patients with others who underwent Fontan surgery and received no permanent pacemaker, atrial single-chamber pacemaker, ventricular-based pacing system, or dual-chamber pacing system. No clear choice of pacing modality emerged for the pediatric single-ventricle patient.
Pacemaker Leads in Children
Epicardial versus endocardial pacing sites
The main difference in lead implantation is route of placement. Although the vast majority of adult pacemaker patients have transvenous lead placement, children have an almost even distribution of transvenous and epicardial lead implantation.
Advantages of epicardial implantation include the lack of need to provide vascular continuity with cardiac chambers and avoidance of concerns about venous thrombosis. Disadvantages include more frequent reports of sensing and capture failure, higher rates of insulation and conductor fractures, and the need for an open chest approach (eg, thoracotomy, sternotomy, subxiphoid, subcostal incision).
Advantages of the transvenous route include avoidance of a thoracotomy, lower pacing thresholds (with subsequent longer battery longevity), and lower incidences of exit block and lead fractures. Disadvantages include a slightly higher dislodgment rate (particularly with passive fixation devices), potential venous occlusion, danger of embolic vascular events (especially from an intracardiac shunt), slight risk of endocarditis, and subclavian crush syndrome. Leaving a generous amount of slack in the lead to allow for uncurling may decrease the likelihood of lead fracture or dislodgment with linear growth.
Studies have been performed to estimate the amount of intracardiac lead redundancy necessary to allow for anticipated growth. Twiddler syndrome can also occur in children with potential lead dislodgment, generator migration, or pacing failure due to twisting of leads or generator in the pocket. Significant vascular access challenges can also relate to congenital heart diseases and surgical corrections.
Transvenous pacing leads in children
Transvenous pacing certainly is feasible in infants and small children. Smaller pacemaker generators and thinner lead diameters now simplify placement of permanent transvenous pacing systems. However, easier placement of transvenous leads in small patients does not imply superiority over other methods. Current practice suggests that transvenous pacing leads routinely can be placed in children who weigh more than 10 kg. This figure is likely to continue to decrease as pacing technology continues to reduce lead body diameter. However, because of continued growth and vigorous activity, pediatric patients have lead fracture and failure rates distinctly higher than adults. Actual survival comparisons have been performed for transvenous pacing leads in children. These comparisons show progressive lead failure over time from fracture, insulation discontinuities, adapter/header failures, or pacing exit block.
Fixation mechanisms in transvenous leads are divided into active-fixation tips and passive-fixation leads. In general, modern active-fixation leads are now more commonly used in children because of the easier removal, if necessary.
Active-fixation leads have a screw on the end that penetrates the endocardium. These mechanisms either are covered in a dissolvable material (eg, gelatin, sugar cap) to protect the delicate veins during insertion or have an intricate screw extension-retraction mechanism, allowing the operator to enter the vein and cardiac chambers without an exposed screw. Advantageously, active-fixation leads can be fixated almost anywhere in the endocardium; they may be especially valuable for patients with left ventricular lead placements (eg, corrected transposition of great arteries) or for patients who lack a right atrial appendage (eg, most postoperative patients with congenital heart disease). Active-fixation transvenous leads are removed more easily, even after implantation for many years. Ease of removal is a distinct advantage for young patients who may need multiple pacemaker system replacements over a lifetime.
Passive-fixation mechanisms use small tines or fins near the distal tip, which become entrapped in the right ventricular trabeculations and lodge within scar over time. These leads do not require a screw-in device but are facilitated by placement in a trabeculated region, which may not be routine in patients with congenital heart disease. Passive-fixation leads are more difficult to extract when implanted for long periods and may be less appropriate for pediatric patients because multiple revisions are anticipated.
Tips of leads may have special coatings to improve pacing characteristics or to decrease surrounding tissue inflammation. The most common is a steroid-eluting tip, which continually disperses a tiny amount of dexamethasone (or other corticosteroid) into the local tip-tissue interface. These steroid-eluting leads, available in both passive-fixation and active-fixation tips, prevent subacute threshold rise, which is seen several weeks after lead implantation. This benefit can be critically important in children, who typically have a greater inflammatory response to tissue injury and larger threshold rise. Titanium nitride and other metallic compounds also have been used to increase surface area at tip-tissue interface; this increased surface area should improve pacing and sensing performance.
Epicardial pacing leads in children
Until recently, epimyocardial pacing was the most common pediatric pacing application. Epicardial pacing now is primarily used when transvenous pacing is contraindicated or for patients undergoing concomitant heart surgery. Contraindications to transvenous pacing include prosthetic tricuspid valves, right-to-left intracardiac shunts, congenital heart disease, surgery precluding transvenous access to cardiac chambers, recurrent transvenous lead dislodgment, and, probably, minimum patient size.
Preoperative Details
Provide a thorough and adequate explanation of pacemaker implantation procedures to the patient. Document indications for permanent pacing and outline the plan for route of access. Make relevant surgical decisions after comprehensive consideration of the following factors:
- Transvenous versus epicardial approach
- Single-chamber versus dual-chamber system versus cardiac resynchronization therapy (CRT) system
- Vascular access and continuity
- Prepectoral versus submuscular pocket
- Handedness of patient and left-sided or right-sided implant
- Presence of structural heart disease, intracardiac shunts, and obstruction to the right heart chambers
- Relevant medical, surgical, and anesthesia history
- Allergies
- Risks of procedure, including pacemaker-specific risks
- Finite battery longevity, lead failure, and likely potential for reoperation
Intraoperative Details
A sterile environment is absolutely essential for implantation. Proper facilities include an operating room, cardiac catheterization laboratory, or electrophysiology laboratory. The implantation procedure may be performed under general or local anesthesia, depending on patient age and route of implantation.
For the transvenous approach, one can perform either a cephalic vein cutdown or percutaneous subclavian (or axillary) vein puncture to access the venous system. Position a wire in the right heart with pacing leads positioned in the right atrium or ventricle. Testing is performed using cables to a pacing system analyzer, which can ascertain adequate sensing of intrinsic waves, capture thresholds, and lead impedances. The generator is then connected to the leads, and a pacemaker pocket is fashioned either prepectorally or subpectorally, usually using blunt dissection and/or cautery. The generator is placed in the pocket, and the incision is closed in multiple layers.
The epicardial approach is typically performed via subcostal, subxiphoid, thoracotomy, or sternotomy procedures. The pacing leads are attached to epicardial surfaces and then tested for capture, sensing, and lead impedances. Similar to the transvenous procedure, a pocket, typically in the subrectus region of the abdomen (or in the pectoral region), is created, with subcutaneous tunneling of leads from epicardial sites to the pocket.
Postoperative Details
In general, most patients remain hospitalized for 12-48 hours, depending on age, complexity, and route of access.
Postoperative patients may resume normal activities of daily living other than several weeks' restriction from heavy lifting, extreme stretching of the accessed shoulder (for transvenous implants), and vigorous activities. These restrictions are particularly important following passive lead implantation to avoid dislodgement. The incision needs to be kept clean and dry and typically heals within 7-10 days.
Prophylactic antibiotics after the first 24 hours have not been demonstrated to reduce risk of pacemaker system or pocket infection. Patients are instructed to immediately report any symptoms of possible infection.
For patients who have newly implanted cardiac resynchronization therapy (CRT) devices, clinicians may choose to optimize the system (specifically the pacemaker timings) using echocardiography.
Follow-up
Follow-up is routine and simplified. During the initial few months following surgery, evaluate the patient to assess for a possible rise in capture thresholds, secondary to inflammation and exit block. Program a safety margin to avoid possible loss of capture because of a subacute threshold rise, which may be seen in the first several weeks, particularly with epimyocardial implants and/or nonsteroid eluting leads.
Transtelephonic pacing system evaluation is simple, convenient, and relatively inexpensive, allowing follow-up with fewer cardiology office visits. These systems have become more sophisticated and more automated over the past few years, allowing extensive pacemaker system information to be transmitted over the telephone and internet.
For patients who are pacemaker-dependent, dizziness, presyncope, or syncope warrants a full device interrogation of both leads and the pulse generator to ensure proper function of the device.
Complications
Complications involve immune response to artificial materials and response of the body to the pacemaker system.
Pacemaker generators are typically very reliable and have a low failure rate. The lithium iodide battery has a limited longevity of 5-15 years. Battery depletion is not a complication but a normal occurrence. Pacing leads are more prone to failure, particularly in children. Leads may fail at the conductor wires or in insulation material (polyurethane or silicone). Lead failure typically results in inappropriate sensing or capture (underpacing or overpacing).
Infection of the pacemaker system is a serious complication and almost always necessitates complete system removal, intravenous antibiotics, and system replacement at a remote site. However, in selected individualized cases, pacemaker system infection can occasionally be effectively treated with a prolonged course of antibiotics, without system removal.
Twiddler syndrome is an interesting finding caused by repetitive and often unintentional twisting of the generator in the pacemaker pocket, causing lead dislodgement or fracture and pacemaker failure.5 It is most commonly observed in patients with behavioral issues.
Finally, chronic right ventricular pacing over long periods (eg, decades) has been shown in a small group of patients to lead to decreased cardiac function.
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References
Cecchin F, Frangini PA, Brown DW, et al. Cardiac Resynchronization Therapy (and Multisite Pacing) in Pediatrics and Congenital Heart Disease: Five Years Experience in a Single Institution. J Cardiovasc Electrophysiol. Sep 3 2008;[Medline].
Dubin AM, Janousek J, Rhee E, et al. Resynchronization therapy in pediatric and congenital heart disease patients: an international multicenter study. J Am Coll Cardiol. Dec 20 2005;46(12):2277-83. [Medline].
Epstein AE, DiMarco JP, Ellenbogen KA, et al. ACC/AHA/HRS 2008 Guidelines for Device-Based Therapy of Cardiac Rhythm Abnormalities: a report of the American College of Cardiology/American Heart Association Task Force on Practice Guidelines (Writing Committee to Revise the ACC/AHA/NASPE 2002 Guideline Update for Implantation of Cardiac Pacemakers and Antiarrhythmia Devices) developed in collaboration with the American Association for Thoracic Surgery and Society of Thoracic Surgeons. J Am Coll Cardiol. May 27 2008;51(21):e1-62. [Medline].
Fishberger SB, Wernovsky G, Gentles TL, et al. Long-term outcome in patients with pacemakers following the Fontan operation. Am J Cardiol. Apr 15 1996;77(10):887-9. [Medline].
Berul CI, Hill SL, Estes NA 3rd. A teenager with pacemaker twiddler syndrome. J Pediatr. Sep 1997;131(3):496-7. [Medline].
Alexander ME, Cecchin F, Walsh EP, Triedman JK, Bevilacqua LM, Berul CI. Implications of implantable cardioverter defibrillator therapy in congenital heart disease and pediatrics. J Cardiovasc Electrophysiol. Jan 2004;15(1):72-6. [Medline].
Alpern D, Uzark K, Dick M 2nd. Psychosocial responses of children to cardiac pacemakers. J Pediatr. Mar 1989;114(3):494-501. [Medline].
Andersen HR, Thuesen L, Bagger JP, Vesterlund T, Thomsen PE. Prospective randomised trial of atrial versus ventricular pacing in sick-sinus syndrome. Lancet. Dec 3 1994;344(8936):1523-8. [Medline].
Benjacholamas V, Chotivittayatarakorn P, Lertsupchareon P, et al. Single midline approach for permanent pacemaker implantation in children. Asian Cardiovasc Thorac Ann. Mar 2003;11(1):11-3. [Medline].
Berul C, Hill S, Mack K. VDDR pacing in children and young adults. HeartWeb. 1998;4:110002-8.
Berul CI, Barrett KS. Unique Aspects of Pacemaker Implantation in Pediatrics. In: Walsh EP, Saul JP, Triedman JK (Editors). Current Concepts of Pediatric Electrophysiology. Baltimore: Lippincott Williams & Wilkins; 2001:301-317.
Berul CI, Cecchin F. Indications and techniques of pediatric cardiac pacing. Expert Rev Cardiovasc Ther. Jul 2003;1(2):165-76. [Medline].
Berul CI, Murphy JD. Nocturnal enuresis secondary to heart block: report of cure by cardiac pacemaker implantation. Pediatrics. Aug 1993;92(2):284-5. [Medline].
Bevilacqua L, Hordof A. Cardiac pacing in children. Curr Opin Cardiol. Jan 1998;13(1):48-55. [Medline].
Bruckheimer E, Berul CI, Kopf GS, et al. Late recovery of surgically-induced atrioventricular block in patients with congenital heart disease. J Interv Card Electrophysiol. Jun 2002;6(2):191-5. [Medline].
Case CL, Gillette PC, Zeigler V, Sade RM. Problems with permanent atrial pacing in the Fontan patient. Pacing Clin Electrophysiol. Jan 1989;12(1 Pt 1):92-6. [Medline].
Chintala K, Forbes TJ, Karpawich PP. Effectiveness of transvenous pacemaker leads placed through intravascular stents in patients with congenital heart disease. Am J Cardiol. Feb 1 2005;95(3):424-7. [Medline].
Connolly SJ, Kerr C, Gent M, Yusuf S. Dual-chamber versus ventricular pacing. Critical appraisal of current data. Circulation. Aug 1 1996;94(3):578-83. [Medline].
DeMaso DR, Lauretti A, Spieth L, et al. Psychosocial factors and quality of life in children and adolescents with implantable cardioverter-defibrillators. Am J Cardiol. 2004;93:582-7. [Medline].
Epstein MR, Walsh EP, Saul JP, et al. Long-term performance of bipolar epicardial atrial pacing using an active fixation bipolar endocardial lead. Pacing Clin Electrophysiol. May 1998;21(5):1098-104. [Medline].
Fortescue EB, Berul CI, Cecchin F, Walsh EP, Triedman JK, Alexander ME. Comparison of modern steroid-eluting epicardial and thin transvenous pacemaker leads in pediatric and congenital heart disease patients. J Interv Card Electrophysiol. Oct 2005;14(1):27-36. [Medline].
Fortescue EB, Berul CI, Cecchin F, Walsh EP, Triedman JK, Alexander ME. Patient, procedural, and hardware factors associated with pacemaker lead failures in pediatrics and congenital heart disease. Heart Rhythm. Jul 2004;1(2):150-9. [Medline].
Friedman RA, Moak JP, Garson A Jr. Active fixation of endocardial pacing leads: the preferred method of pediatric pacing. Pacing Clin Electrophysiol. Aug 1991;14(8):1213-6. [Medline].
Friedman RA, Van Zandt H, Collins E, LeGras M, Perry J. Lead extraction in young patients with and without congenital heart disease using the subclavian approach. Pacing Clin Electrophysiol. May 1996;19(5):778-83. [Medline].
Galdston R, Gamble WJ. On borrowed time: observations on children with implanted cardiac pacemakers and their families. Am J Psychiatry. Jul 1969;126(1):104-8. [Medline].
Gillette PC, Zeigler VL, Winslow AT, Kratz JM. Cardiac pacing in neonates, infants, and preschool children. Pacing Clin Electrophysiol. Nov 1992;15(11 Pt 2):2046-9. [Medline].
Gregoratos G, Abrams J, Epstein AE, et al. ACC/AHA/NASPE 2002 guideline update for implantation of cardiac pacemakersand antiarrhythmia devices: summary article: a report of the American College of Cardiology/AmericanHeart Association Task Force on Practice Guidelines (ACC/AHA/NASPE Committee t. Circulation. Oct 15 2002;106(16):2145-61. [Medline].
Gregoratos G, Cheitlin MD, Conill A. ACC/AHA guidelines for implantation of cardiac pacemakers and antiarrhythmia devices: a report of the American College of Cardiology/American Heart Association Task Force on Practice Guidelines (Committee on Pacemaker Implantation). J Am Coll Cardiol. Apr 1998;31(5):1175-209. [Medline].
Horenstein MS, Karpawich PP. Pacemaker syndrome in the young: do children need dual chamber as the initial pacing mode?. Pacing Clin Electrophysiol. May 2004;27(5):600-5. [Medline].
Lamas GA, Pashos CL, Normand SL, McNeil B. Permanent pacemaker selection and subsequent survival in elderly Medicare pacemaker recipients. Circulation. Feb 15 1995;91(4):1063-9. [Medline].
Lau YR, Gillette PC, Buckles DS, Zeigler VL. Actuarial survival of transvenous pacing leads in a pediatric population. Pacing Clin Electrophysiol. Jul 1993;16(7 Pt 1):1363-7. [Medline].
Link MS, Hill SL, Cliff DL, et al. Comparison of frequency of complications of implantable cardioverter- defibrillators in children versus adults. Am J Cardiol. Jan 15 1999;83(2):263-6, A5-6. [Medline].
Lukl J, Doupal V, Heinc P. Quality-of-life during DDD and dual sensor VVIR pacing. Pacing Clin Electrophysiol. Nov 1994;acing.(11 Pt 2):1844-8. [Medline].
Mathony U, Schmidt H, Groger C, et al. Optimal maximum tracking rate of dual-chamber pacemakers required by children and young adults for a maximal cardiorespiratory performance. Pacing Clin Electrophysiol. May 2005;28(5):378-83. [Medline].
Molina JE, Dunnigan AC, Crosson JE. Implantation of transvenous pacemakers in infants and small children. Ann Thorac Surg. Mar 1995;59(3):689-94. [Medline].
Mueller X, Sadeghi H, Kappenberger L. Complications after single versus dual chamber pacemaker implantation. Pacing Clin Electrophysiol. Jun 1990;13(6):711-4. [Medline].
Noiseux N, Khairy P, Fournier A, Vobecky SJ. Thirty years of experience with epicardial pacing in children. Cardiol Young. Oct 2004;14(5):512-9. [Medline].
Ovsyshcher IE, Hayes DL, Furman S. Dual-chamber pacing is superior to ventricular pacing: fact or controversy? [comment]. Circulation. Jun 16 1998;97(23):2368-70. [Medline].
Paridon SM, Karpawich PP, Pinsky WW. Exercise performance with single chamber rate-responsive pacing in congenital heart defects after operation. Am J Cardiol. Nov 1 1991;68(11):1231-3. [Medline].
Ragonese P, Guccione P, Drago F, et al. Efficacy and safety of ventricular rate responsive pacing in children with complete atrioventricular block. Pacing Clin Electrophysiol. Apr 1994;17(4 Pt 1):603-10. [Medline].
Rosenthal E, Bostock J. Use of an atrial loop to extend the duration of endocardial pacing in a neonate. Pacing Clin Electrophysiol. Oct 1997;20(10 Pt 1):2489-91. [Medline].
Serwer GA, Mericle JM, Armstrong BE. Epicardial ventricular pacemaker electrode longevity in children. Am J Cardiol. Jan 1 1988;61(1):104-6. [Medline].
Silka MJ, Bar-Cohen Y. Pacemakers and implantable cardioverter-defibrillators in pediatric patients. Heart Rhythm. Nov 2006;3(11):1360-6. [Medline].
Silvetti MS, Drago F. Upgrade of single chamber pacemakers with transvenous leads to dual chamber pacemakers in pediatric and young adult patients. Pacing Clin Electrophysiol. Aug 2004;27(8):1094-8. [Medline].
Smerup M, Hjertholm T, Johnsen SP, et al. Pacemaker implantation after congenital heart surgery: risk and prognosis in a population-based follow-up study. Eur J Cardiothorac Surg. Jul 2005;28(1):61-8. [Medline].
Spotnitz HM. Transvenous pacing in infants and children with congenital heart disease. Ann Thorac Surg. Mar 1990;49(3):495-6. [Medline].
Stojanov P, Vranes M, Velimirovic D, et al. Prevalence of venous obstruction in permanent endovenous pacing in newborns and infants: follow-up study. Pacing Clin Electrophysiol. May 2005;28(5):361-5. [Medline].
Sutton R, Bourgeois I. Cost benefit analysis of single and dual chamber pacing for sick sinus syndrome and atrioventricular block. An economic sensitivity analysis of the literature. Eur Heart J. Apr 1996;17(4):574-82. [Medline].
Further Reading
Keywords
pacemaker therapy, pacing, permanent pacing, pacemaker implantation, transvenous pacemaker, implanted cardioverter/defibrillator, ICD, congenital heart disease, sinus node dysfunction, atrioventricular node function, heart rate, long QT syndrome, cardiomyopathy, cardiac resynchronization therapy, CRT, congenital atrioventricular block, acquired atrioventricular block, congenital AV block, acquired AV block, systemic lupus erythematosus, SLE, congenital heart block, Lyme disease, viral myocarditis, symptomatic bradycardia, ventricular dysfunction, or low cardiac output, ventricular tachycardia, bradycardia-tachycardia syndrome, tetralogy of Fallot
