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Surgical treatment of accessory atrioventricular pathways and symptomatic tachycardia in children and young adults
Surgical Treatment of Accessory Atrioventricular Pathways and Symptomatic Tachycardia in Children and Young Adults DAVID R. HOLMES, Jr., MD, GORDON K. DANIELSON, MD, BERJWRD J. GERSH, MB, ChB, Phil, MICHAEL J. OSBORN, MD, DCUGLAS L. WOOD, h/D, CHRISTOPHER McLARAN, MD, DECLAN D. S&RUE, MD, MRCP, CO-BURN J. PORTER, MD, and STEPHEN C. HAMMILL, MD
Twenty-seven patients aged 21 years or younger (mean 15) with symptomatic tachycardia underwent operation for ablation of an accessory atrioventricuiar pathway. Six patients had associated Ebstein’s malformation of the tricuspid valve. Supraventricular tachycardia had been present for a mean of 5 years. At electrophysioiogic study, 4 patients were found to have 2 accessory pathways. Left ventricular free wail pathways were found in 14 patients, right ventricular free wail pathways in 10 and septai pathways in 6. Successful initial ablation of all the pathways was achieved in 26 of the 27
Accessory atrioventricular (AV) pathways may present in children and young adults as asymptomatic electrocardiographic abnormalities, supraventricular tachycardia (SVT) or life-threatening ventricular arrhyth-
mias.l-g Traditionally, control
medications
have been used to
or prevent
arrhythmias; surgical ablation has been used often as a “last resort.” The prolonged need for drug therapy and the potential for toxicity give cause for concern in pediatric and young adult patients. Although surgical ablation has been well described in older patients,10-20 limited information is available on the
outcome of surgery, especially in children or young adults. Continued evaluation is necessary in deciding whether surgery remains a therapeutic “last resort” modality
or one that requires
earlier consideration.
Accordingly, we report the result of surgery for accessory AV pathways in 27 patients aged 21 years or younger. From the Mayo Clinic and Mayo Foundation, Rochester, Minnesota. Manuscript received October 29, 1984: revised manuscript received February 19, 1985, accepted February 20.1985. kfWss for reprints: David R. Holntes, Jr., MD, Mayo Clinic, 200 First Street SW, Rochester, Minnesota 55905.
patients. No patient died perioperativeiy and none had persistent complete heart block. During a mean follow-up of 11 months, no patient had recurrence of an arrhythmia related to the accessory pathway. Thus, the surgical treatment of children and young adults with accessory atrioventricular pathways and symptomatic supraventricular tachycardia is safe and effective. For these patients, unless the tachycardia can be easily controlled with a minimal number of drugs and adverse effects, surgical ablation should be considered early in the clinical course. (Am J Cardiol 1965;55:1509-1512)
Methods From April 1972 through June 1984,27 patients aged 21 years or younger with preexcitation syndrome alone or in combination with Ebstein’s malformation underwent an electrophysiologicslly guided operation to ablate sn accessory pathway. The decision to operate was based on consideration of the location of the pathway; early in our experience, the risks and outcome of operation were judged to be more favorable with free wall pathways than septsl pathways. Our continuing experience has indicated that the latter can be ablated with similar risks and results. In addition to the pathway location, other factors were important, including frequency and severity of SVT, the refractory period of the pathway, shortest RR interval during atria1 fibrillation, previous drug therapy and patient and family desires. Preoperative electrophysiologic evaluation: Electrophysiologic assessment was performed as previously reported.‘6 Cardioactive drug treatment was discontinued 48 hours before study. Multiple electrode catheters were positioned for recording and stimulation. At the time of study, the following variables were evaluated4~21-s’:location of the accessory pathway, using atrial pacing, and the retrograde atrisl activation sequence during programmed ventricular stimulation and orthodromic SVT; confirmation of AV reentrant SVT using the accessory pathway; anterograde refractory
1510
ACCESSORY ATRIOVENTRICULARPATHWAYS AND TACHYCARDIA
TABLE I Clinical and Electrophyslologlc Characterlstlcs of Patlents wlih Accessory Atrloventrlcular Pathways and Symptomatic Tachycardla Preoperative Case
sex & Age (yr)
Duration of Symptoms W
Clinical Arrhythmia
No. of Drugs Tried
Arrhythmia Induced at EP Study
No. of Pathways
Location of Pathways
Operative Findings No. of Pathways
Location of Pathways
Patients Without Ebstein’s Malformation Fl8 Ml5 F17 z!: !9 F13 Fl9 Ml8 Ml2 M20 Fl8 Ml4 F15 Ml4 Ml8 Ml7 Ml3 Ml4 F16
PSVT PSVT PSVT PSVT PSVT PSVT PSVT PSVT PSVT PSVT PSVT PSVT/A A fib-F PSVT PSVT/A PSVT PSVT/A PSVTIA PSVT PSVT PSVT
4 3 4 1 f 1 1 t fib-F
f
fib-F
: 2
fib-F fib-F
: t i
K SVT SVTIA SVTIA SVT SVT SVT/A SVT/A SVT/A SVTIA SVT/A A fib-F SVT SVTlA SVT SVT SVT/A SVT/A SVT/A SVT/A
; fib-F fib-F
i :
fib-F fib-F fib-F fib-F fib-F
: 1
fib-F
:
i 1 1
:
fib-F fib-F fib-F fib-F
: i
RFW
RFW
;FW LFW
:FW
E RFW, S
:it S LFW’ RFW, S Kit RFW LFW LFW LFW LFW-RFW LFW LFW Et RFW RFW
LFW RFW, S LFW LFW RFW
EE LFW : : :
LFW-RFW LFW LFW LFW LFW RFW RFW
Patients with Ebstein’s Malformation F20 A fib-F RFW’ No EP study ... Fl8 1: PSVT : SVT/A fib-F RFW : F15 PSVT : RFW, S 2 F13 ii t & F13 ET 2 : :FW : A fib-F 1 A fib-F Ml5 3.1 1 S 2 Electrocardiographic findings consistent with right-sided free-wall accessory pathway. A fib-F = atrial fibrillation/flutter; EP = electrophysiologic; LFW = left ventricular free wall; PSVT = paroxysmal supraventricular RFW = right ventricular free wall: S = septum; SVT = supraventricular tachycardla.
RFW RFW RFW, S RFW RFW RFW, S
l
period and anterograde and retrograde conduction properties of the accessory pathway; presence or absence of associated abnormalities, including multiple accessory pathways, enhanced AV nodal conduction, and SVT due to other mechanisms (for example, AV nodal reentry); ventricular response if atria1 fibrillation/flutter could be induced by rapid atria1 pacing; and response to intravenous antiarrhythmic drugs. Surgical approach: Operation was performed through a median sternotomy, as previously described.16 The atrial insertion site was localized by epicardial atrial mapping during ventricular pacing or during spontaneous or induced WT. The location of the ventricular insertion was determined by epicardial ventricular mapping during paced atria1 rhythm.‘5Js~ss After the epicardial atrial insertion was identified, the appropriate atria1 chamber was entered. The endocardial point corresponding to the epicardial location of the pathway was determined.16 The atrium was then divided from the AV valve for 2 to 3 cm on each side of the reference point. For left-sided pathways, the epicardium was not incised; for right-sided pathways, the incision was carried through the epicardium. Septal pathways were approached using the method described by Sealy and Gallagher.12 In 1 recent patient with a septal pathway, a cryoprobe was used for ablation. Dissected areas were electrocoagulated and closed with a double row of sutures. Among the patients with Ebstein’s malformation, a plastic repair of the tricuspid valve using a posterior tricuspid anuloplasty, as previously described, was used in 4 patients, the tricuspid valve was replaced with a bioprosthesis in 1 patient and the Ebstein’s malformation was mild and not repaired in 1.29After discontinuation of bypass, atria1 pacing was used to confirm the lack of anterograde
tachycardia;
preexcitation and the presence of normal AV nodal behavior, and ventricular pacing was used to document normal ventriculoatrial conduction. An attempt was made to reinduce WT. Atrial and ventricular temporary pacing wires were placed for postoperative assessment of the conduction system.
Results Clinical features: There were 13 male and 14 female patients, mean age 15 years (range 5 to 20). Six patients had associated Ebstein’s malformation of the tricuspid valve (Table I). Twenty-one patients had no associated cardiovascular disease. All 27 patients had a history consistent with SVT. Of the 27 patients, 24 had a history of paroxysmal SVT, with a mean rate of 257 beats/min (range 175 to 300), and 3 had paroxysmal atrial fibrillation only. Four of the patients had a history of both paroxysmal SVT and atrial flutter or fibrillation. All 27 patients had been symptomatic with tachycardia: 10 had recurrent syncope, 14 had recurrent light-headedness, near-syncope or weakness, and 3 had recurrent palpitations. All patients had had previous physician evaluations and often multiple hospitalizations for evaluation and treatment of tachycardia, which had been present for a mean of 5 years. Twenty-five of the patients had previously been treated with medications, including class 1 antiarrhythmic drugs, /3-adrenergic blockers, digoxin and calcium
channel antagonists.
The mean number
of
June
medication trials used in these patients was 2.3 per patient. Preoperative electrophysiologic assessment: Twenty-six patients underwent preoperative electrophysiologic testing. The 1 patient who did not have a preoperative electrophysiologic study had an Ebstein’s malformation that required surgery. His electrocardiogram was consistent with a right-sided free-wall accessory pathway, and this was confirmed at the time of intraoperative mapping. At electrophysiologic study, 4 patients each had 2 accessory pathways. Left ventricular free wall pathways were most common, being found in 14 patients. Six patients had septal pathways and 10 had right ventricular free-wall pathways (Table I). The accessory pathways were found to participate in inducible macroreentrant SVT (mean rate 192 beats/ min) in 25 of the 26 patients undergoing electrophysiologic study. Fifteen patients, including 2 patients without macroreentrant tachycardia, had inducible atrial flutter or atria1 fibrillation. Surgical results: No patient died perioperatively and no patient had permanent AV block. One patient with a posterior septal pathway had transient complete AV block less than 1 month in, duration but subsequently returned to normal sinus rhythm. The accessory pathways were localized in all patients. In the 26 patients who underwent preoperative electrophysiologic assessment, the location corresponded to that predicted by the preoperative electrophysiologic study in 24. In 2 patients, there was a discrepancy: In 1 patient a right free wall pathway was found, in contrast to the preoperative study, which had indicated a septal pathway, and in another patient a second unsuspected right free wall pathway was identified (Table I). The pathways in both patients were successfully ablated. In the 1 patient without a preoperative study, the location corresponded to that predicted by the 12-lead electrocardiogram. At operation, the delta wave was initially abolished in all patients with anterograde preexcitation. Immediately after ablation, SVT could not be reinduced in any of the 27 patients. In 1 patient, the delta wave returned within 6 hours after operation. This patient had a left posteromedial free wall pathway. He underwent reoperation 24 hours later. Again there was only temporary success in abolishing the delta wave. Before hospital dismissal, this patient underwent electrophysiologic assessment, at which time SVT could not be induced and the conduction properties of the accessory pathway had slowed. Among the patients with freewall accessory pathways, this was the only patient who did not have successful ablation. All 6 patients with septal pathways had successful ablation without permanent AV block. Follow-up: A mean follow-up of 11 months (range 1 month to 6 years) was available for these patients. There have been no late deaths. No patients have had tachycardia related to the accessory pathway, including the patients with multiple pathways and the patient with electrocardiographic evidence of persistent preexcitation. One patient had the reappearance of a
1, 1985
THE AMERICAN
JOURNAL
OF CARDIOLOGY
Volume
55
1511
delta wave at 5 months after operation; this has not been associated with tachycardia. Therefore, 2 patients (7%) at follow-up had a persistent delta wave that either was not abolished at surgery (1 patient) or had reappeared (1 patient). None have AV reentrant tachycardia. Discussion In the treatment of children and young adults who have preexcitation syndromes, the chronic recurring nature of the symptoms must be considered.3031 Problems of particular concern include the potential psychologic sequelae of chronic cardiac disability at a young age, because of recurrent SVT, and the need for chronic medications. Traditionally, to prevent SVT, antiarrhythmic medications have been used either alone or in combination. Generally, class I agents are most effective. The side effects of these drugs, however, are frequent and often limit their applicability and efficacy. This is a particular problem in patients who have infrequent but very symptomatic SVT and who must take medications daily to prevent further attacks. These problems are magnified in children in whom the lengthy duration of medical therapy and potential for side effects are paramount. Surgical ablation of an accessory pathway, a curative procedure, is very attractive in this regard, although it has been used only as a last resort in many centers. In adult patients, the results of surgery are well known; as many as 90% of patients are free of tachycardia after operation.1sJg*20 Data on the results of this procedure in children are sparse. The extent to which the outcome of surgery in adults can be extrapolated to children is therefore uncertain. Anatomic and technical considerations may make the operation itself more difficult in children. Often, there is associated congenital heart disease,30 as in 22% of our patients. In addition, particularly in infants and small children, preoperative and intraoperative mapping and ablation could be more difficult because of the size of the heart. Reports from other centers on the results of surgery for preexcitation syndromes have not differentiated pediatric patients from adult patients. 4~13p20 It is difficult, therefore, to obtain data specifically related to pediatric and young adult patients. In an initial series, Gillette et ale reported on 10 patients who were 6 months to 15 years old when they underwent operation for preexcitation syndromes. One patient died perioperatively, but this death was not related to an arrhythmia, and 8 of 10 patients had no further episodes of SVT. In the 27 patients in our series, there was no operative mortality and no persistent AV block. At follow-up, 2 patients had a persistent delta wave that either was not abolished at surgery (1 patient) or had reappeared (1 patient), and neither of these had paroxysmal SVT. However, follow-up in these 2 patients was short-3 months in 1 patient and 10 months in the other-and with longer follow-up, SVT may recur. These surgical results are notable in that 22% of patients also had associated corrective surgical procedures for congenital heart disease performed at the same time, and despite the fact that multiple pathways were found in 4 patients and septal pathways in 6 patients.
1512
ACCESSORY
ATRIOVENTRICULAR
PATHWAYS
AND TACHYCARDIA
Surgical ablation is not without attendant potential morbidity and mortality. It requires analysis of the location of the pathway before ablation, documentation of the pathway as part of the reentrant circuit, and evaluation for other forms of tachycardia, such as AV nodal reentry.4J8 It also requires detailed operative assessment, localization of the pathway, and precise surgical techniques for ablation.15Js The major advantage in experienced hands is that successful surgical ablation obviates the need for continued medical treatment for recurrent, often disabling symptoms. The specific recommendations for surgical ablation of accessory pathways remain controversial and depend on multiple factors. It is generally agreed that patients who are symptomatic and those who have atria1 fibrillation and short refractory periods of the accessory pathway with the potential for sudden death should be considered for surgery. Patients with tachycardia who are undergoing surgery for associated congenital heart disease, as was seen in 6 patients in our series, should also be studied with a view toward ablation of the pathway at surgery for their primary congenital abnormality. Finally, given the good results presented in the present study and elsewhere with a safe and effective operation, one may argue that in children and young adults-unless SVT can be easily controlled with a minimal number of drugs and side effects-surgical ablation should be performed earlier in the clinical course. An operative approach may come to be considered the more conservative treatment compared with life-long therapy using antiarrhythmic drugs. References
8. 9. 10. 11. 12. 13. 14. 15. 16. 17.
10. 19. f9
22. 23. 24. 25.
1. Giardina ACV, Ehlera KH, Engle MA. Wolff-Parkinson-White syndrome in f$a&ts.nd children: a long-term follow-up study. Br Heart J 1972;34:
26.
2. Woltt 0s; Han J, Curran J. Wofff-Parkinson-Whii syndrome In the neonate. Am J Cardiol 1978;41:559-563. 3. Mantakaa ME, &Cue CM, Miller WW. Natural history of Wolff-Parkinson-White syndrome discovered In infancy. Am J Cardiol 1978;41: 1097-l 103. 4. Gallagher JJ, Prltchett ELC, Scaly WC, Kaeell J, Wallace AG. The preexcltation syndromes. Prog Cardlovasc Dia 1978;20:285-327. 5. Cayb$l FWF, Smtth R+ Gallagher JJ, Prltchett ELC, Fatlace AG Atrlal ;F;llatron In the preexcrtatlon syndrome. Am J Cardrol 1977;40:514-
27.
6. Gill&e PC, Garson A Jr,.Kugler JD. Wolff-Parkinson-White syndrome in chlfdren: electrophyslologrc and pharmacologic characterlstlcs. Clrculatlon 1979;60:1487-1495. 7. Lubbers WJ. Loeekoot TO, Anderson RH, Wellens HJJ. Paroxysmal su-
28. 29. 30. 31.
praventricular tachycardia in infancy and childhood. Eur J Cardiol 1974; 291-99. Fasth A. Wofff-Parkinsc&Vhiie syndrome: a fatal case in a girl with no other heart disease. Acta Paediatr Stand 1975;64:138-140. Gillette PC, Garson A Jr, Kugter JD, Cooley DA, Llmer A, MoNamara DG. Surgical treatment of supraventricular tachycardla in infants and children. Am J Cardiol 1980;46:281-284. Gallagher JJ, Gilbert M, Svenson RH, Scaly WC, Kasell J, Wallace AG. Wolff-Parkinson-White syndrome: the problem, evaluation, and surgical correction. Circulatim 1975;51:767-785. Scaly WC, Wallace AJ, Ramming KP, Gallagher JJ, Sveneon RH. An im oroved ooeration for the definitive treatment of Wolff-Parkinson-White syndrome. Ann Thorac Surg 1974;17:107-113. Sealy WC, Gallagher JJ. The surgical approach to the septal area of the heart based on experiences with 45 patients with Kent bundles. J Thorac Cardiovasc Surg 1980;79:542-551. Iwa T, Kawasujl M, Mlsakl T, lwase T, Magara T. Localization and interruption of accessory conduction pathway in the Wolff-Parkinson-White syndrome. J Thorac Cardiovasc Surg 1980;80:271-279. Sealy WC, Gallagher JJ, Prltchett ELC. The surgical anatomy of Kent bundles based on electrophyslological mapping and surgical exploration. J Thorac Cardiovasc Surg 1978;76:804-815. Gallagher JJ, Sealy WC, Kaeell J. lntraoperative mapping studies in the Wolff-Parkinson-White syndrome. PACE 1979;2:523-537. Holmes DR Jr, Osborn MJ, Gersh B, Maloney JD, DanIeleon OK. The Wolff-Parkinson-White syndrome: a surgical approach. Mayo Clin Proc 1982;57:345-350. Scaly WC, Prltchetl ELC, Gallagher JJ, Kasell J. The surgical problems with the identification and interruption of the bundle of Kent. In: Narula OS, ed. Cardiac Arrhythmias: Electrophysiology, Diagnosis and Management. Baltimore: Williams 8 Wilkins, 1979;636-651. Gallagher JJ, Svenson RH, Scaly WC, Wallace AG. The Wolff-Parkinson-white syndrome and the preexcitation dysrhythmiaa: medical and surgical management. Med Clin North Am 1976 Jan;60:101-123. gr JL. Surgery for cardiac arrhythmias. Curr Prob Cardiol 1983;8:1Scaly WC. Direct surgery for arrhythmias. Chest 1982;82:338-344. Sveneon RH, Miller HC, Gallagher JJ, Wallace AG. Electrophysiological evaluation of the Wolff-Parkinson-White syndrome: problems in assessing antegrade and retrograde conduction over the accessory pathway. Circulation 1975;52:552-562. Tonkln AM, Miller HC, Svenson RH, Wallace AG, Gallagher JJ. Refractory periods of the accessory pathway in the Wolff-Parkinson-White syndrome. Circulation 1975;52:563-569. Gallagher JJ, Sealy WC, Keeell J, Wallace AG. Multiple accessory pathways in patients with the pm-excitation syndrome. Circulation 1976:54: 571-591. Edvatdeeon N, BfometMn P, Ofssoa BB. Identification of multiple pathways in the Wolff-Parkinson-White syn&orne: diagnostic problems and therapeutic implications. Cardiology 1984;71:20-29. Smith WM, Broughton A, Relter MJ, Benson DW Jr, Grant AO, Gallagher JJ. Bystander accessory pathway during AV node m-entrant tachycardia. PACE 1983;6:537-547. Clnca J, Valle V, Gutlerrez L, Flgueras J, Rlue J. Reciprocating tachycardii using bilateral anomalous pathways: electrophysiologic and clinical irnollcations. Circulation 1980:62:657-661. iwa T, Magara T, Watanabe’ Y, Kawasujl M, Mleakl T. Interruption of multiple accessory conduction pathways in the Wolff-Parkinson-White syndrome. Ann Thorac Sur 1980;30:313-323. Gallagher JJ, Kaeell J, I ealy WC, Prltchetl ELC, Wallace AG. Epicardial rnaooina in the Wolff-Parkinson-White svndrome. Circulation 1978:57: 854-863. Danielson OK, Fueler V. Surgical repair of Ebstein’s anomaly. Ann Surg 1982;196:499-503. Garson A Jr, Gillette PC. Electrophysiologic studies of supraventricular tachycardtt in chit&en. 1. Clinlcal-electrophysiologic cwelatkms. Am Heart J 1981;102:233-250. Gareon A Jr, Gillette PC, McNamara DG: Supraventricular tachycardia in children: clinical features, response to treatment, and long-term follow-up in 217 patients. J Pediatr 1981;98:875-882.
Twenty-seven patients aged 21 years or younger (mean 15) with symptomatic tachycardia underwent operation for ablation of an accessory atrioventricuiar pathway. Six patients had associated Ebstein’s malformation of the tricuspid valve. Supraventricular tachycardia had been present for a mean of 5 years. At electrophysioiogic study, 4 patients were found to have 2 accessory pathways. Left ventricular free wail pathways were found in 14 patients, right ventricular free wail pathways in 10 and septai pathways in 6. Successful initial ablation of all the pathways was achieved in 26 of the 27
Accessory atrioventricular (AV) pathways may present in children and young adults as asymptomatic electrocardiographic abnormalities, supraventricular tachycardia (SVT) or life-threatening ventricular arrhyth-
mias.l-g Traditionally, control
medications
have been used to
or prevent
arrhythmias; surgical ablation has been used often as a “last resort.” The prolonged need for drug therapy and the potential for toxicity give cause for concern in pediatric and young adult patients. Although surgical ablation has been well described in older patients,10-20 limited information is available on the
outcome of surgery, especially in children or young adults. Continued evaluation is necessary in deciding whether surgery remains a therapeutic “last resort” modality
or one that requires
earlier consideration.
Accordingly, we report the result of surgery for accessory AV pathways in 27 patients aged 21 years or younger. From the Mayo Clinic and Mayo Foundation, Rochester, Minnesota. Manuscript received October 29, 1984: revised manuscript received February 19, 1985, accepted February 20.1985. kfWss for reprints: David R. Holntes, Jr., MD, Mayo Clinic, 200 First Street SW, Rochester, Minnesota 55905.
patients. No patient died perioperativeiy and none had persistent complete heart block. During a mean follow-up of 11 months, no patient had recurrence of an arrhythmia related to the accessory pathway. Thus, the surgical treatment of children and young adults with accessory atrioventricular pathways and symptomatic supraventricular tachycardia is safe and effective. For these patients, unless the tachycardia can be easily controlled with a minimal number of drugs and adverse effects, surgical ablation should be considered early in the clinical course. (Am J Cardiol 1965;55:1509-1512)
Methods From April 1972 through June 1984,27 patients aged 21 years or younger with preexcitation syndrome alone or in combination with Ebstein’s malformation underwent an electrophysiologicslly guided operation to ablate sn accessory pathway. The decision to operate was based on consideration of the location of the pathway; early in our experience, the risks and outcome of operation were judged to be more favorable with free wall pathways than septsl pathways. Our continuing experience has indicated that the latter can be ablated with similar risks and results. In addition to the pathway location, other factors were important, including frequency and severity of SVT, the refractory period of the pathway, shortest RR interval during atria1 fibrillation, previous drug therapy and patient and family desires. Preoperative electrophysiologic evaluation: Electrophysiologic assessment was performed as previously reported.‘6 Cardioactive drug treatment was discontinued 48 hours before study. Multiple electrode catheters were positioned for recording and stimulation. At the time of study, the following variables were evaluated4~21-s’:location of the accessory pathway, using atrial pacing, and the retrograde atrisl activation sequence during programmed ventricular stimulation and orthodromic SVT; confirmation of AV reentrant SVT using the accessory pathway; anterograde refractory
1510
ACCESSORY ATRIOVENTRICULARPATHWAYS AND TACHYCARDIA
TABLE I Clinical and Electrophyslologlc Characterlstlcs of Patlents wlih Accessory Atrloventrlcular Pathways and Symptomatic Tachycardla Preoperative Case
sex & Age (yr)
Duration of Symptoms W
Clinical Arrhythmia
No. of Drugs Tried
Arrhythmia Induced at EP Study
No. of Pathways
Location of Pathways
Operative Findings No. of Pathways
Location of Pathways
Patients Without Ebstein’s Malformation Fl8 Ml5 F17 z!: !9 F13 Fl9 Ml8 Ml2 M20 Fl8 Ml4 F15 Ml4 Ml8 Ml7 Ml3 Ml4 F16
PSVT PSVT PSVT PSVT PSVT PSVT PSVT PSVT PSVT PSVT PSVT PSVT/A A fib-F PSVT PSVT/A PSVT PSVT/A PSVTIA PSVT PSVT PSVT
4 3 4 1 f 1 1 t fib-F
f
fib-F
: 2
fib-F fib-F
: t i
K SVT SVTIA SVTIA SVT SVT SVT/A SVT/A SVT/A SVTIA SVT/A A fib-F SVT SVTlA SVT SVT SVT/A SVT/A SVT/A SVT/A
; fib-F fib-F
i :
fib-F fib-F fib-F fib-F fib-F
: 1
fib-F
:
i 1 1
:
fib-F fib-F fib-F fib-F
: i
RFW
RFW
;FW LFW
:FW
E RFW, S
:it S LFW’ RFW, S Kit RFW LFW LFW LFW LFW-RFW LFW LFW Et RFW RFW
LFW RFW, S LFW LFW RFW
EE LFW : : :
LFW-RFW LFW LFW LFW LFW RFW RFW
Patients with Ebstein’s Malformation F20 A fib-F RFW’ No EP study ... Fl8 1: PSVT : SVT/A fib-F RFW : F15 PSVT : RFW, S 2 F13 ii t & F13 ET 2 : :FW : A fib-F 1 A fib-F Ml5 3.1 1 S 2 Electrocardiographic findings consistent with right-sided free-wall accessory pathway. A fib-F = atrial fibrillation/flutter; EP = electrophysiologic; LFW = left ventricular free wall; PSVT = paroxysmal supraventricular RFW = right ventricular free wall: S = septum; SVT = supraventricular tachycardla.
RFW RFW RFW, S RFW RFW RFW, S
l
period and anterograde and retrograde conduction properties of the accessory pathway; presence or absence of associated abnormalities, including multiple accessory pathways, enhanced AV nodal conduction, and SVT due to other mechanisms (for example, AV nodal reentry); ventricular response if atria1 fibrillation/flutter could be induced by rapid atria1 pacing; and response to intravenous antiarrhythmic drugs. Surgical approach: Operation was performed through a median sternotomy, as previously described.16 The atrial insertion site was localized by epicardial atrial mapping during ventricular pacing or during spontaneous or induced WT. The location of the ventricular insertion was determined by epicardial ventricular mapping during paced atria1 rhythm.‘5Js~ss After the epicardial atrial insertion was identified, the appropriate atria1 chamber was entered. The endocardial point corresponding to the epicardial location of the pathway was determined.16 The atrium was then divided from the AV valve for 2 to 3 cm on each side of the reference point. For left-sided pathways, the epicardium was not incised; for right-sided pathways, the incision was carried through the epicardium. Septal pathways were approached using the method described by Sealy and Gallagher.12 In 1 recent patient with a septal pathway, a cryoprobe was used for ablation. Dissected areas were electrocoagulated and closed with a double row of sutures. Among the patients with Ebstein’s malformation, a plastic repair of the tricuspid valve using a posterior tricuspid anuloplasty, as previously described, was used in 4 patients, the tricuspid valve was replaced with a bioprosthesis in 1 patient and the Ebstein’s malformation was mild and not repaired in 1.29After discontinuation of bypass, atria1 pacing was used to confirm the lack of anterograde
tachycardia;
preexcitation and the presence of normal AV nodal behavior, and ventricular pacing was used to document normal ventriculoatrial conduction. An attempt was made to reinduce WT. Atrial and ventricular temporary pacing wires were placed for postoperative assessment of the conduction system.
Results Clinical features: There were 13 male and 14 female patients, mean age 15 years (range 5 to 20). Six patients had associated Ebstein’s malformation of the tricuspid valve (Table I). Twenty-one patients had no associated cardiovascular disease. All 27 patients had a history consistent with SVT. Of the 27 patients, 24 had a history of paroxysmal SVT, with a mean rate of 257 beats/min (range 175 to 300), and 3 had paroxysmal atrial fibrillation only. Four of the patients had a history of both paroxysmal SVT and atrial flutter or fibrillation. All 27 patients had been symptomatic with tachycardia: 10 had recurrent syncope, 14 had recurrent light-headedness, near-syncope or weakness, and 3 had recurrent palpitations. All patients had had previous physician evaluations and often multiple hospitalizations for evaluation and treatment of tachycardia, which had been present for a mean of 5 years. Twenty-five of the patients had previously been treated with medications, including class 1 antiarrhythmic drugs, /3-adrenergic blockers, digoxin and calcium
channel antagonists.
The mean number
of
June
medication trials used in these patients was 2.3 per patient. Preoperative electrophysiologic assessment: Twenty-six patients underwent preoperative electrophysiologic testing. The 1 patient who did not have a preoperative electrophysiologic study had an Ebstein’s malformation that required surgery. His electrocardiogram was consistent with a right-sided free-wall accessory pathway, and this was confirmed at the time of intraoperative mapping. At electrophysiologic study, 4 patients each had 2 accessory pathways. Left ventricular free wall pathways were most common, being found in 14 patients. Six patients had septal pathways and 10 had right ventricular free-wall pathways (Table I). The accessory pathways were found to participate in inducible macroreentrant SVT (mean rate 192 beats/ min) in 25 of the 26 patients undergoing electrophysiologic study. Fifteen patients, including 2 patients without macroreentrant tachycardia, had inducible atrial flutter or atria1 fibrillation. Surgical results: No patient died perioperatively and no patient had permanent AV block. One patient with a posterior septal pathway had transient complete AV block less than 1 month in, duration but subsequently returned to normal sinus rhythm. The accessory pathways were localized in all patients. In the 26 patients who underwent preoperative electrophysiologic assessment, the location corresponded to that predicted by the preoperative electrophysiologic study in 24. In 2 patients, there was a discrepancy: In 1 patient a right free wall pathway was found, in contrast to the preoperative study, which had indicated a septal pathway, and in another patient a second unsuspected right free wall pathway was identified (Table I). The pathways in both patients were successfully ablated. In the 1 patient without a preoperative study, the location corresponded to that predicted by the 12-lead electrocardiogram. At operation, the delta wave was initially abolished in all patients with anterograde preexcitation. Immediately after ablation, SVT could not be reinduced in any of the 27 patients. In 1 patient, the delta wave returned within 6 hours after operation. This patient had a left posteromedial free wall pathway. He underwent reoperation 24 hours later. Again there was only temporary success in abolishing the delta wave. Before hospital dismissal, this patient underwent electrophysiologic assessment, at which time SVT could not be induced and the conduction properties of the accessory pathway had slowed. Among the patients with freewall accessory pathways, this was the only patient who did not have successful ablation. All 6 patients with septal pathways had successful ablation without permanent AV block. Follow-up: A mean follow-up of 11 months (range 1 month to 6 years) was available for these patients. There have been no late deaths. No patients have had tachycardia related to the accessory pathway, including the patients with multiple pathways and the patient with electrocardiographic evidence of persistent preexcitation. One patient had the reappearance of a
1, 1985
THE AMERICAN
JOURNAL
OF CARDIOLOGY
Volume
55
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delta wave at 5 months after operation; this has not been associated with tachycardia. Therefore, 2 patients (7%) at follow-up had a persistent delta wave that either was not abolished at surgery (1 patient) or had reappeared (1 patient). None have AV reentrant tachycardia. Discussion In the treatment of children and young adults who have preexcitation syndromes, the chronic recurring nature of the symptoms must be considered.3031 Problems of particular concern include the potential psychologic sequelae of chronic cardiac disability at a young age, because of recurrent SVT, and the need for chronic medications. Traditionally, to prevent SVT, antiarrhythmic medications have been used either alone or in combination. Generally, class I agents are most effective. The side effects of these drugs, however, are frequent and often limit their applicability and efficacy. This is a particular problem in patients who have infrequent but very symptomatic SVT and who must take medications daily to prevent further attacks. These problems are magnified in children in whom the lengthy duration of medical therapy and potential for side effects are paramount. Surgical ablation of an accessory pathway, a curative procedure, is very attractive in this regard, although it has been used only as a last resort in many centers. In adult patients, the results of surgery are well known; as many as 90% of patients are free of tachycardia after operation.1sJg*20 Data on the results of this procedure in children are sparse. The extent to which the outcome of surgery in adults can be extrapolated to children is therefore uncertain. Anatomic and technical considerations may make the operation itself more difficult in children. Often, there is associated congenital heart disease,30 as in 22% of our patients. In addition, particularly in infants and small children, preoperative and intraoperative mapping and ablation could be more difficult because of the size of the heart. Reports from other centers on the results of surgery for preexcitation syndromes have not differentiated pediatric patients from adult patients. 4~13p20 It is difficult, therefore, to obtain data specifically related to pediatric and young adult patients. In an initial series, Gillette et ale reported on 10 patients who were 6 months to 15 years old when they underwent operation for preexcitation syndromes. One patient died perioperatively, but this death was not related to an arrhythmia, and 8 of 10 patients had no further episodes of SVT. In the 27 patients in our series, there was no operative mortality and no persistent AV block. At follow-up, 2 patients had a persistent delta wave that either was not abolished at surgery (1 patient) or had reappeared (1 patient), and neither of these had paroxysmal SVT. However, follow-up in these 2 patients was short-3 months in 1 patient and 10 months in the other-and with longer follow-up, SVT may recur. These surgical results are notable in that 22% of patients also had associated corrective surgical procedures for congenital heart disease performed at the same time, and despite the fact that multiple pathways were found in 4 patients and septal pathways in 6 patients.
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ACCESSORY
ATRIOVENTRICULAR
PATHWAYS
AND TACHYCARDIA
Surgical ablation is not without attendant potential morbidity and mortality. It requires analysis of the location of the pathway before ablation, documentation of the pathway as part of the reentrant circuit, and evaluation for other forms of tachycardia, such as AV nodal reentry.4J8 It also requires detailed operative assessment, localization of the pathway, and precise surgical techniques for ablation.15Js The major advantage in experienced hands is that successful surgical ablation obviates the need for continued medical treatment for recurrent, often disabling symptoms. The specific recommendations for surgical ablation of accessory pathways remain controversial and depend on multiple factors. It is generally agreed that patients who are symptomatic and those who have atria1 fibrillation and short refractory periods of the accessory pathway with the potential for sudden death should be considered for surgery. Patients with tachycardia who are undergoing surgery for associated congenital heart disease, as was seen in 6 patients in our series, should also be studied with a view toward ablation of the pathway at surgery for their primary congenital abnormality. Finally, given the good results presented in the present study and elsewhere with a safe and effective operation, one may argue that in children and young adults-unless SVT can be easily controlled with a minimal number of drugs and side effects-surgical ablation should be performed earlier in the clinical course. An operative approach may come to be considered the more conservative treatment compared with life-long therapy using antiarrhythmic drugs. References
8. 9. 10. 11. 12. 13. 14. 15. 16. 17.
10. 19. f9
22. 23. 24. 25.
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2. Woltt 0s; Han J, Curran J. Wofff-Parkinson-Whii syndrome In the neonate. Am J Cardiol 1978;41:559-563. 3. Mantakaa ME, &Cue CM, Miller WW. Natural history of Wolff-Parkinson-White syndrome discovered In infancy. Am J Cardiol 1978;41: 1097-l 103. 4. Gallagher JJ, Prltchett ELC, Scaly WC, Kaeell J, Wallace AG. The preexcltation syndromes. Prog Cardlovasc Dia 1978;20:285-327. 5. Cayb$l FWF, Smtth R+ Gallagher JJ, Prltchett ELC, Fatlace AG Atrlal ;F;llatron In the preexcrtatlon syndrome. Am J Cardrol 1977;40:514-
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6. Gill&e PC, Garson A Jr,.Kugler JD. Wolff-Parkinson-White syndrome in chlfdren: electrophyslologrc and pharmacologic characterlstlcs. Clrculatlon 1979;60:1487-1495. 7. Lubbers WJ. Loeekoot TO, Anderson RH, Wellens HJJ. Paroxysmal su-
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