birth; he was treated initially with a transvenous pacemaker, then exteriorized myo¬ cardial wires, and finally a permanent im¬

Pacemaker Therapy in Children planted pacemaker congenital L-transposition septal defect, vessels, pulmonary With Complete Heart Block by Robert E. Stanton, MD; Bert W. Meyer, MD

George G. Lindesmith, MD;

Permanent pacemaker therapy in children with complete heart block is necessary occasionally. Ten patients ranging in age from 8 months to 15 years were treated with an im-

planted P-wave, synchronous epicardial pacemaker. Indications for implantation were persisting postsurgical heart block, congestive failure, syncopal attacks, and arrhythmias. There were two deaths not attributed to pacemaker malfunction. The remaining eight children have been followed up for 38 to 108 months. There have been 27 pulse generator replacements. Twenty-three were for battery exhaustion, three for electromechanical failure, and one was due to arrhythmia. Rhythm disturbances have occurred on eight occasions. There have been no infections. It is concluded that the implanted P\x=req-\ wave synchronous pacemaker is an effective method of therapy when indicated for children with complete heart block. use of an implantable cardiac pacemaker has become an estab¬ lished method of therapy for complete heart block in symptomatic adults.1'3 Experience with cardiac pacemakers in childhood has been limited.4" How¬

The ever,

permanent pacemaker therapy

in children with complete heart block is occasionally necessary.7 9 Of 59 chil¬ dren with complete heart block, ten patients ranging in age from 8 months to 15 years were treated with an implanted P-wave synchronous epicardial pacemaker. The indications

for

implantation

were

persisting

Received for publication May 31, 1974; ac10. From the divisions of cardiology (Dr. Stanton) and thoracic surgery (Drs. Lindesmith and Meyer), Childrens Hospital of Los Angeles; and the department of pediatrics (Dr. Stanton) and surgery (Drs. Lindesmith and Meyer), University of Southern California School of Medicine, Los An-

cepted Sept

geles. Reprint requests to Childrens Hospital of Los Angeles, 4650 Sunset Blvd, Los Angeles, CA 90027 (Dr. Stanton).

postsurgical complete heart block, syncopal attacks, congestive heart failure, or arrhythmias. The P-wave synchronous pacemaker was used be¬

of its more physiological func¬ tion and ability to serve as a standby unit if sinus rhythm recurs, thus pre¬ venting competitive arrhythmias. An additional advantage is that with early battery depletion, it reverts to fixed-rate pacing rather than allow¬ ing complete heart block to redevelop as may occur with fixed-rate units. It is the purpose of this article to present our experience with the implantable synchronous cardiac pace¬ maker in these ten children. cause

at 8 months of age. The other child with block had an of the great associated ventricular func¬ valve tional obstruction of the the mitral valve apparatus, and a Blalock anastomosis. Congestive failure en¬ sued, and at the time of surgical correc¬ tion, a permanent pacemaker was inserted. The last child had L-transposition of the great vessels, complete heart block, and re¬ current ventricular tachycardia and fibril¬ lation. The sites of the battery unit implanta¬ tion have been reported in detail"' and in¬ cluded the anterior aspect of the abdomi¬ nal wall, the anterior aspect of the chest wall, the intrathoracic position, the subdiaphragmatic position, and the intrapelvic position. All required a thoracotomy in order to position the myocardial electrodes on both the left atrial appendage and the left ventricle. The pulse generator site de¬ pended on the size of the child. None of these positions presented undue problems either initially or at the time of battery unit replacement. Temporary transvenous pacemakers were inserted from either the femoral or external jugular vein, with placement of the pacing catheter in the apex of the right ventricle.

RESULTS

SUBJECTS AND METHODS The clinical data of the ten patients are summarized in the Table. There were five boys and five girls. Six children had per¬ sisting postsurgical complete heart block. Two children had congenital heart block associated with congestive heart failure. One child had an acquired heart block of unknown cause and had had two syncopal episodes, and one child had complete heart block and arrhythmias associated with congenital heart disease. The surgical block developed in three children with endocardial cushion defects, in one with a ventricular septal defect, in one with te¬ tralogy of Fallot, and in one with a congenitally corrected transposition (Ltransposition) of the great vessels and associated ventricular septal defect. In all three children with endocardial cushion de¬ fects, the complete heart block reverted to sinus rhythm in the immediate postopera¬ tive period, only to recur four months, five months, and five years postoperatively. One of these children had a ventricular septal defect component. One child with familial congenital complete heart block developed congestive failure on the day of

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These children have been followed up for 38 to 108 months with an aver¬ age of 73 months. One child was lost to follow-up after 54 months. The fol¬ lowing problems were encountered: Death

Battery depletion Arrhythmia Electromechanical failure

Myocardial fibrosis Infection

0 23 8 4 3 0

There have been two deaths not re¬ lated to pacemaker malfunction. One death was due to bronchopneumonia developing two months following pacemaker implantation in the child with L-transposition of the great ves¬ sels and ventricular septal defect re¬ pair. The other death occurred 13 days following implantation in the infant with L-transposition of the great ves¬ sels and arrhythmias. Cardiovascular collapse occurred suddenly, and al¬ though initial resuscitation attempts were successful, the myocardial re¬ sponse was poor and the infant died

Summary of Clinical Case, Sex, Age (yr) 1, M, 7f 2, M, 8 3, 4, 5, 6, 7, 8, 9,

F, 3 M, 15 F, 3 F, 3 F, 2/3 F, 10 M, 5

Data

on

Ten Children With

Cause

Diagnosis'"

Surgical Surgical Surgical Acquired Surgical Surgical Congenital Surgical Congenital

VSD & L-TGV ECD & VSD ECD No lesion Tetralogy of Fallot VSD Familial ECD

VSD, pulmonary stenosis, L-TGV, Blalock

Symptoms Syncope None None

Syncope None None

Congestive failure None

Congestive failure

anastomosis L-TGV

Arrhythmia following abbreviations are used: VSD ventricular septal defect; position of great vessels; ECD endocardlal cushion defect, t Deaths unrelated to pacemaker function. 10, M, 5/6f

*

Congenital

The

pacing only (cardiac origin: myocardial fibrosis)

Fixed-rate

Synchronous Pacemaker

=

Implant Date May 1964 Feb 1965 Sept 1965 April 1966 June 1966 Dec 1968 June 1969 Feb1970 June 1971

Jan 1973 L-TGV

:

L-trans-

=

Electrocardiograms demonstrating fixed-rate pacing on preexercise strip (case 4). Exer¬ strip indicates increase in atrial rate with appropirate synchronous pacing. Postexercise strip once again illustrates fixed-rate pacing with atrial rate slower than pacemaker fixed

cise

rate.

func¬ tion. There have been 27 pulse generator replacements in the surviving eight children. The most common problem was battery depletion, and this oc¬ curred on 23 occasions with an aver¬ age battery life of 16 months. The range was 3 to 27 months. Electrome¬ chanical failure was the cause of re¬ placement in three children and one replacement was due to arrhythmia.

despite continued pacemaker

There were 37 surgical procedures in these ten children, with the number of operations ranging from one to seven per child. There have been no infections. Rhythm distrubances developed in eight children and are summarized as follows: Intermittent synchronous pacing 1 Pacemaker malfunction Cardiac origin: sinus bradycardia 3

Competitive arrhythmia

4

tery depletion.

COMMENT

Recorded

experience with cardiac

in infants and children has been meager. This in part may be

pacemakers 1

3

There were four children in whom there was only intermittent P-wave synchronous pacing. This was due to pacemaker malfunction in one pa¬ tient and was resolved when the bat¬ tery unit was replaced after 16 months due to battery depletion. In three children there appeared to be sinus bradycardia with a take-over of fixed-rate pacing at rest, but as the atrial rate increased with exercise there was the appearance of sinus rhythm (Figure). A competitive arrhythmia in which the pacemakeroriginated beats interfered with intrinsic beats producing a nonfunc¬ tional rhythm and syncopal attacks developed in one child. The problem was solved when the arrhythmia was terminated by replacing the battery unit. Fixed-rate nonsynchronous Pwave pacing was present in three children and appeared to be due to myocardial fibrosis and diminished amplitude of the atrial impulse. In the one child with familial congenital block, it was believed that this was due to congenital atrial fibrosis. At the time of the last battery unit change, a fixed-rate unit with a rate of 80 was implanted. In the other two children, this was a developmental phenomenon in that, initially, P-wave synchronous pacing was present, but after 52 months and four pacemaker changes in the first child and 65 months and four pacemaker changes in the second child, synchronous pac¬ ing no longer persisted. It was also noted that on a number of occasions, P-wave synchronous pacing did not develop immediately following im¬ plantation but did develop within a few days, presumably as edema about the electrodes subsided. Complete heart block developed at the time of battery exhaustion on five occasions. This was associated with syncopal episodes in one child. Fixed-rate pac¬ ing developed without incident in the remaining children with early bat¬

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related to the reluctance to report iso¬ lated cases or very small series. How¬ ever, it is more probably due to the infrequent occurrence of sympto¬ matic complete heart block in chil¬

dren. In a cooperative study encom¬ passing 46 centers and 599 patients with congenital complete heart block, Michaelsson and Engle reported on 33 patients treated with an implanted pacemaker." Surgically induced com¬ plete heart block is becoming less frequent as knowledge and technique improve.1213 In addition, the longterm management of postoperative complete heart block remains contro¬ versial.14-16 Further, the development of acquired nonsurgical complete

heart block in the normal child or in association with congenital heart dis¬ ease is uncommon." Thus, the poten¬ tial number of children requiring a permanent pacemaker remains small. Yet, the need is obvious as attested to by reports on the natural history of complete heart block in infants and children. Deaths occur in infancy due to congestive failure and in childhood due to Stokes-Adams attacks.1118·19 Although the long-term management of surgical block remains unsettled, it is evident that death may occur sud¬ denly, often with the first StokesAdams attack, and may occur many years

following operation.2" Further,

there is no certain method of pre¬ dicting the clinical course of postoper¬ ative complete heart block.16 We believe that complete heart block persisting four weeks following operation should be treated with a permanent cardiac pacemaker. This is based on our experience with four of five children with surgical complete heart block who survived the immedi¬ ate postoperative period only to die suddenly and without warning three weeks to 33 months following oper¬ ation. This is contrasted with five of six children treated with a permanent pacemaker who have survived. Al¬ though this experience is small, it is similar to other reports.1316 It has also been our experience and that of others that Stokes-Adams at¬ tacks may terminate in death in chil¬ dren who have congenital or acquired nonsurgical complete heart block."·18 Therefore, the development of

Stokes-Adams episodes in such pa¬ tients represents a clear indication for therapy with a permanent pace¬ maker. Fortunately, death seldom oc¬ curs with the first syncopal attack, but may occur with subsequent epi¬ sodes. Following two such attacks, we believe that permanent pacemaker therapy is justified. It is recognized that not all cardiologists would accept this opinion, and it is also recognized that there are patients who have sur¬ vived numerous Stokes-Adams at¬ tacks. However, their numbers are few indeed.21 Congestive failure and low cardiac output secondary to complete heart block, especially in infancy, is our third indication for pacemaker ther¬ apy. Temporary pacing may be suffi¬ cient in some situations, but perma¬ nent pacing may be necessary as in patient 7 whose heart was paced from the first day of life because of conges¬ tive failure and low cardiac output. Fatalities reported in the past may well have been avoided with cardiac pacing, as suggested by the dramatic improvement in congestive failure and Stokes-Adams attacks noted by Trassier and associates.9 The occur¬ rence of complete heart block with congenital cardiac defects may also require pacemaker therapy in order to allow for optimal management of the cardiac lesion. Implanted pace¬ makers have also been utilized in certain types of dysrhythmias in adults,22·23 but may have a role in chil¬ dren as well. Certainly in case 10 the recurring episodes of ventricular tachycardia and fibrillation were pre¬ vented by the normal rates achieved with a pacemaker. Several types of pacemakers are now available.24 These include fixedrate units, synchronous units, and de¬ mand or standby systems. The fixedrate unit has been used in most of the reported cases in infants and chil¬ dren. It has the advantage of requir¬ ing fewer electrodes and produces less battery drain. A special appli¬ cation of the fixed-rate unit is the radiofrequency pacemaker, which has the advantage of an external pulse generator thus making it more suit¬ able for small infants.6 Other fixedrate units have been manufactured

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with a smaller pulse generator for in¬ fant use. We have used only the P-wave syn¬ chronous pacemaker in these chil¬ dren.25 2,i It has the ability to increase cardiac rate in response to the pa¬ tient's activity, and we believe it as¬ sures more normal cardiac function because of this. The ability of the syn¬ chronous pacemaker to function as a standby unit if sinus rhythm returns is a distinct advantage in that it will

prevent competitive dysrhythmias.

An additional advantage is that with early battery depletion, the unit re¬

fixed-rate system rather allowing complete heart block to recur as may develop with fixed-rate units. The disadvantages of the syn¬ verts to

a

than

chronous epicardial pacemaker are similar to all implanted pacemakers in that they are relatively large and require thoracotomy and frequent pulse generator changes. In addition, the more complex circuitry of the synchronous pacemaker may lead to shorter battery life. Sensing dis¬ orders due to atrial fibrosis that lead to fixed-rate pacing have also de¬ veloped with the P-wave synchronous

pacemaker. However,

no

problems

have been encountered with either implantation or battery change. The sites chosen for implantation have been dictated by the size of the child, as previously noted.10 The principal problem related to the implanted permanent pacemaker has been the need for repeated re¬ placement of the pulse generator be¬ cause of battery depletion. Presently, our indications for battery unit

change include competitive arrhyth¬ mias, ineffectual low-amplitude elec¬ trical impulses, complete battery de¬ pletion with resumption of clinical heart block, and fixed-rate pacing in a unit that previously had paced with P-wave synchronization. In those units in which P-wave sensing has

been lost due to apparent atrial fibro¬ sis, the battery unit has been changed automatically at the end of the ex¬ pected pacemaker life of approxi¬ mately 24 months. The frequent operations and hospitalizations are not only costly, but produce discomfort and anxiety in the children and their families. Yet, as

better batteries and

pulse generators developed, including nuclear-pow¬ ered generators, the major problem of rapid battery depletion and replace¬ are

will

be overcome.37'29 Dis¬ of the myocardial elec¬ placement trodes due to growth is a potential problem, but has not developed in our patients. Other problems include pro¬ gressive elevation of pacing thresh¬ olds due to myocardial fibrosis either at the atrial level preventing synchro¬ nous pacing as in three of our cases, or at the ventricular level interfering with ventricular pacing. However, more sensitive pickup systems should overcome this problem. The other rhythm disturbances have interfered with function or required positive ac¬ tion on only two occasions. The one episode of intermittent pacing was resolved with battery unit change, as was one episode of competitive arrhythmia. The remaining episodes were relatively minor problems. Electromechanical difficulties includ¬ ing broken leads, disrupted connecment

tions, and

current leaks have been noted in other centers and have oc¬ curred on four occasions in our experi¬ ence. The problems of the synchro¬ nous pacemaker have been amply reported.3031 Although infection has been a concern to all authors, it has not occurred in our patients with implanted pacemakers. Exteriorized wires did produce an infection, which suggests that totally implanted pace¬ makers are superior even for young infants. We wish to add a word regarding care of the child with postsurgical heart block or the symptomatic child before implantation of a permanent pacemaker. It has been our practice to insert temporary myocardial elec¬ trodes at the time of surgical heart block or a temporary transvenous pacemaker in late heart block occur¬ ring beyond the intraoperative period and maintain an appropriate heart rate until such time as surgical im¬ plantation is to be carried out. We have also, on occasion, inserted tern-

porary transvenous pacemakers in asymptomatic children with complete heart block in order to avoid the possibility of Stokes-Adams attacks during surgical procedures. Further¬ more, temporary transvenous pace¬ makers may be helpful in controlling certain tachyarrhythmias.32 ·33 How¬ ever, it would not seem that perma¬ nent transvenous pacemakers with their intracardiac foreign body effect and potential problems associated with growth would be a suitable solu¬ tion to the permanent pacing needs of infants and children. The difficulties encountered with the implantable epicardial pacemaker in children have been no different than those reported in adults. Despite the problems, these children appear happy and are able to carry on the ac¬ tivities of their peers. Our experience suggests that the P-wave synchro¬ nous implantable pacemaker is a suc¬ cessful approach to the management of complete heart block in infants and children when necessary.

References 1. Zoll PM, Frank HA, Zarsky LRN, et al: Long-term electric stimulation of the heart for Stokes-Adams disease. Ann Surg 154:330-346, 1961. 2. Chardack WM, Gage AA, Federico AJ, et al: The long-term treatment of heart block. Prog Cardiovasc Dis 9:105-135, 1966. 3. Dack S: Pacemaker treatment of heart block: The permanent transvenous catheter pacemaker. JAMA 201:868-870, 1967. 4. Liu

L, Griffith SP, and Gerst PH: Imcardiac pacemakers in children. Am J Cardiol 20:639-647, 1967. 5. Gamble WJ, Gross RE, Nadas AS: pacemakers in Experience with implanted pediatric patients (P), abstracted. Circulation 36 (suppl 2):117, 1967. 6. Glenn WWL, Leuchtenberg ND, Heekeren DMV, et al: Heart block in children. J Thorac Cardiovasc Surg 58:361-372, 1969. 7. Martin MV, Lime AB, Almeida CS, et al: Implantation of Chardack-Greatbatch adjustable rate and current pacemaker in a 4-month old infant. Pediatrics 37:323\x=req-\ 328, 1966. 8. Veracochea O, Zerpa F, Morales J, et al: Pacemaker implantation in familial congenital A-V block complicated by Adams\x=req-\ Stokes attacks. Br Heart J 29:810-812, 1967. 9. Trussler GA, Mustard WI, Keith JD: The role of pacemaker therapy in congenital complete heart block. J Thorac Cardio-

planted

Surg 55:105-111, 1968. 10. Lindesmith GG, Stiles QR, Meyer BW, et al: Experience with an implantable synchronous pacemaker in children. Ann Thorac Surg 6:358-364, 1968.

vasc

11. Michaelsson J, Engle MH: Congenital complete heart block: An international study of the natural history. Cardiovasc Clin 4:85-101, 1973. 12. Lauer RM, Ongley PA, Dushane JW, et al: Heart block after repair of ventricular septal defect in children. Circulation 22:526-534, 1960. 13. Sayed HM: Complete heart block following open heart surgery. J Cardiovasc Surg 6:426-435, 1965. 14. Hurwitz RA, Riemenschneider TA, Moss AJ: Chronic postoperative heart block in children. Am J Cardiol 21:185-189, 1968. 15. Murphy DA, Tynan M, Graham GR, et al: Prognosis of complete atrioventricular dissociation in children with open-heart surgery. Lancet 1:750-752, 1970. 16. Fryda RJ, Kaplan S, Helmsworth JA: Postoperative complete heart block in children. Br Heart J 33:456-462, 1971. 17. Nakamura FF, Nadas AS: Complete heart block in infants and children. N Engl J Med 270:1261-1268, 1964. 18. Molthan ME, Miller RA, Hastreiter AR, et al: Congenital heart block with fatal Adams-Stokes attacks in childhood. Pediatrics 30:32-41, 1962. 19. Crittenden IH, Latta H, Ticinovich DA: Familial congenital heart block. Am J Dis Child 108:104-108, 1964. 20. Moss AJ, Klyman G, Emmanoulides GC: Late onset complete heart block. Am J Cardiol 30:884-887, 1972. 21. Campbell M, Emanuel R: Six cases of congenital heart block followed for 34-50 years. Br Heart J 29:577-587, 1967. 22. Kitchen JG, Goldreyer RN: Demand

pacemaker for refractory paroxysmal supraventricular tachycardia. N Engl J

Med 287:596-598, 1972. 23. Conde C, Leppo J. Lipski J, et al: The effectiveness of pacemaker insertion (PI) in management of the bradycardia-tachycardia syndrome (BTS), abstracted. Am J Cardiol 31:127, 1973. 24. Lown B, Kosowsky BD: Artificial cardiac pacemakers. N Engl J Med 283:907-916, 971-977, and 1023-1031, 1970. 25. Nathan DA, Center S, Wu CY, et al: An implantable, synchronous pacemaker for the long-term correction of complete heart block. Circulation 37:682-685, 1963. 26. Center S, Nathan D, Wu CY, et al: The implantable synchronous pacer in the treatment of complete heart block. J Thorac Cardiovasc Surg 46:745-754, 1963. 27. Norman JD, Sandberg GW Jr, Huffman FN: Implantable nuclear-powered cardiac pacemakers. N Engl J Med 283:1203-1206, 1970. 28. American patients receive nuclear pacemakers, MEDICAL NEWS. JAMA 222:11\x=req-\ 12, 1972. 29. Furman S, Escher DJW, Parker B: Pacemaker longevity. Am J Cardiol 31:111-114, 1973. 30. Adelman AG, Lopez JF: Arrhythmias associated with the synchronous pacemaker. Am Heart J 74:632-641, 1967. 31. Furman S, Escher DJW, Parker B: The failure of triggered pacemakers. Am Heart J 82:28-38, 1971. 32. Craenen J, Moore D: Stokes-Adams attacks in a small child treated by prolonged use of an indwelling pacing catheter. Pediatrics 39:14-17, 1967. 33. Hunsaker MR, Khoury GH: Management of supraventricular tachycardia by atrial stimulation. J Pediatr 77:454-456, 1970.

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Pacemaker therapy in children with complete heart block.

Permanent pacemaker therapy in children with complete heart block is necessary occasionally. Ten patients ranging in age from 8 months to 15 years wer...
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