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Outcomes of radiofrequency catheter ablation of atrioventricular reciprocating tachycardia in patients with congenital heart disease
Heart Rhythm (2004) 1, 168 –173
www.heartrhythmjournal.com
Outcomes of radiofrequency catheter ablation of atrioventricular reciprocating tachycardia in patients with congenital heart disease Philippe Chetaille, MD,a,b Edward P. Walsh, MD,b John K. Triedman, MDb a
From the Hoˆpital d’Enfants de la Timone, Marseille, France and Children’s Hospital Boston, Boston, Massachusetts.
b
KEYWORDS Radiofrequency catheter ablation; Congenital heart disease; Supraventricular tachycardia
OBJECTIVES Assessment of clinical outcomes of catheter ablation of atrioventricular reciprocating tachycardias in patients with congenital heart disease (CHD). BACKGROUND Atrioventricular reciprocating tachycardias occur in patients with CHD and may be poorly tolerated. METHODS Retrospective review of all 105 such ablations in 83 patients performed between 03/90 and 02/02 at one institution. RESULTS The dominant arrhythmia mechanism was accessory pathway (70 patients, 84%), and the most common indications were drug-refractory tachycardia, life-threatening arrhythmia, and elective presurgical ablation. Congenital heart disease diagnoses were diverse, with one third of patients having Ebstein’s anomaly. Twenty patients (24%) had catheter access limited by prior surgeries or occluded vascular access. Of 109 accessory pathways (APs), 74 (68%) were manifestly preexcited, and 71 (65%) were located on the right atrioventricular groove. Fourteen patients (20%) had multiple pathways. There were 2 major complications (1 death, 1 hemorrhage), and 3 minor complications (5.5% of procedures). Acute success rate was 80% per procedure, 82% for left- and 70% for right-sided APs. Acute success rates for patients with Ebstein’s anomaly were similar to patients with other CHD diagnoses, but Ebstein’s patients were more likely to have recurrence. At 44 ⫾ 35 months follow-up, successful ablation was achieved in 59% of procedures and 68% of patients, with 19 patients (23%) undergoing one or more repeat ablations. CONCLUSIONS Compared to patients with normal cardiac anatomy, patients with CHD of all varieties have lower rates of acute and long-term success for ablation for atrioventricular reciprocating tachycardias. © 2004 Heart Rhythm Society. All rights reserved.
Supraventricular tachycardias may occur in the setting of structural congenital heart disease (CHD) and may compliDr. Chetaille was supported in part by grants from the Agence pour le De´veloppement de la Recherche Me´dicale, Assistance Publique des Hoˆpitaux de Marseille, France and the Association Re´gionale de Cardiologie de Provence, France. Address reprint requests and correspondence: John K. Triedman, MD, 300 Longwood Ave., Boston, Massachusetts 02115. E-mail address: [email protected]. (Received January 29, 2004; accepted March 16, 2004.)
cate their management. Associations between several congenital malformations and accessory pathway (AP)-mediated tachycardias are well described,1– 4 and atrioventricular (AV) reciprocating tachycardias due to AP and AV node reentry have been reported in most other varieties of congenital heart disease with prevalence similar to that seen in the general population.5 Underlying hemodynamic compromise results in tachycardia being poorly tolerated in many of these patients,6 and may also complicate management with antiarrhythmic medications and during perioperative
1547-5271/$ -see front matter © 2004 Heart Rhythm Society. All rights reserved. doi:10.1016/j.hrthm.2004.03.064
Chetaille et al
Ablation in Congenital Heart Disease
periods. Radiofrequency (RF) catheter ablation has been demonstrated to be feasible in this patient population, but available data on outcomes are based either on small series7–11 or multicenter registry analysis.12–14 In this study, we retrospectively analyzed clinical indications and outcomes in a large series of patients with CHD treated at a single institution with RF catheter ablation for AV reciprocating tachycardias.
Methods
169 Recurrence was defined as documented supraventricular tachycardia or reemergence of preexcitation within the successfully ablated population. Undocumented arrhythmia symptoms or performance of another ablation for tachycardia of proven distinct mechanism were not classified as recurrences. Patients who were lost to follow-up were excluded for statistical analysis of recurrence rates. Minor complication was defined as complication that was transient and did not require new therapy. Major complication was defined as death related to procedure or any complication that had significant therapeutic implication.
Study patients
Ablation protocol
All patients with a diagnosis of structural CHD referred to Children’s Hospital Boston for RF catheter ablation of AV reciprocating tachycardia between March 1990 and March 2002 were included in the study group. Complete case identification was ensured by clinical and billing database searches and manual logbook review. For each patient, electrophysiologic data were reviewed to determine acute clinical outcome, and clinical notes from local and referring cardiologists used to ascertain outcome on most recent follow-up evaluation. Follow-up duration was defined as time between first procedure and last clinic visit. The Committee on Clinical Investigation of Children’s Hospital Boston approved the study.
Procedures were usually performed under general anesthesia or, infrequently, conscious sedation. Vascular access for ablation was determined to some extent by patient size and intracardiac anatomy, and typically obtained by femoral veins (87% of cases), with other access used as necessary (internal jugular vein 4%, subclavian vein 3%, femoral artery 6%). Although most patients had an identifiable coronary sinus, its location and course were sometimes aberrant and/or inaccessible, especially in patients who had undergone surgeries involving atrial baffling. Occasionally, an esophageal electrode catheter was used for left atrial timing and/or pacing. Because of associated congenital diagnoses, complete hemodynamic and angiographic studies were performed on the majority of patients prior to electrophysiologic study. Access to the AP was antegrade in 67% of cases, transseptal in 27%, and retrograde in 6% of cases. Standard approaches to substrate diagnosis were applied, including atrial and ventricular extrastimulation protocols, placement of critically timed ventricular extrastimuli, and diagnostic use of isoproterenol and adenosine. After identification of targeted arrhythmia substrates, RF lesions were applied using electrophysiology catheters ranging in diameter from 5 to 7 F and with tip size 4 mm. Rarely, 8-mm-tip or internally cooled ablation catheters were employed in the event of repeated failures of ablation using a 4-mm-tip catheter. RF energy was generated using either a voltage-controlled (Radionics RFG-3C, Radionics, Inc., Burlington, MA) or a temperature-controlled (Atakr, Medtronic Cardiorhythm, San Jose, CA) RF generator. Antegrade and retrograde conduction properties of ablated APs were immediately tested, and attempts made to reinduce the ablated tachycardia using decremental atrial and ventricular extrastimulation protocols. Isoproterenol was routinely used to increase the sensitivity of postablation testing. When additional tachycardia mechanisms deemed to be of potential clinical relevance were identified, mapping and ablation procedures were repeated.
Anatomical classification Anatomical diagnoses were determined from echocardiographic and angiographic data. Patients with isolated findings limited to patent foramen ovale, hemodynamically trivial patent ductus arteriosus, or mitral valve prolapse without significant mitral valve regurgitation were excluded from review. Single ventricle refers to all patients with univentricular physiology and includes all anatomic categories with this physiology. Heterotaxy refers to patients with mixed thoracic and abdominal situs, with anomalies of venous connections to the heart and major intra-cardiac defects in most cases.
Outcome classification Acute success for AP ablation was defined as demonstration of antegrade and retrograde block of at least one targeted pathway and absence of inducible tachycardia after ablation. Failed ablation was defined as continued inducibility of tachycardia, and indeterminate outcome was defined as absence of inducible tachycardia but with failure to demonstrate antegrade and/or retrograde conduction block. Failed ablation and indeterminate outcomes were both counted as failures for statistical purposes. Similarly, acutely successful ablation of AV nodal reentrant tachycardia (AVNRT) and twin AV nodes was defined as absence of dual AV nodal pathway physiology after ablation and noninducibility of tachycardia.
Statistical analysis Aggregate data are presented as mean ⫾ standard deviation or median (range) as appropriate. Univariate analyses
170
Heart Rhythm, Vol 1, No 2, July 2004
Table 1
CHD categories Number (% of population)
CHD Ebstein’s anomaly Single ventricle Atrial septal defect CAVC L-TGA Tetralogy of Fallot Anomalous pulmonary venous connection HCM Other (includes DORV, ventricular septal defect, mital and aortic valve disease, cor triatriatum)
28 (34%) 17 (20%) 8 (9%) 4 (5%) 4 (5%) 3 (4%) 3 (4%) 3 (4%)
13 (15%)
CAVC ⫽ Complete atrioventricular canal; CHD ⫽ Congenital heart disease; DORV ⫽ Double outlet right ventricle; HCM ⫽ Hypertrophic cardiomyopathy; L-TGA ⫽ L-transposition of great arteries. Note that patients may be classified in more than one category.
were performed using chi-square analyses for frequency and t-test for differences in normally distributed means. Significance differences have a P-value of ⱕ .05.
Results During the study period, 105 procedures were performed in 83 patients, with 26 patients undergoing 2 or more ablation procedures. Two additional patients undergoing 3 procedures were excluded from analysis due to insufficient information. The mean age was 11.7 ⫾ 10.3 years (range: 0.2 to 47.2 years), and mean weight was 39.1 ⫾ 27.2 kg (range: 2.5 to 108 kg). Twelve procedures were performed in patients less than or equal to 12 months of age; indications for ablation in these cases were: apparent life-threatening event possibly associated with supraventricular tachycardia (SVT), drug-refractory SVT, and impending surgical atrial septation. Anatomical diagnoses were diverse, with some patients having multiple CHD diagnoses, with the largest single category being Ebstein’s anomaly (28 patients, 34%) (Table 1). Eighteen patients (22%) had AV discordance, and 7 (9%) had heterotaxy syndrome. A mean of 0.8 anti-
Table 2
arrhythmic medications (range: 0 to 2) had been prescribed prior to referral for ablation. Prior cardiac surgery had been performed in 61 patients (74%), and was considered to limit catheter access in 20 (24%), in most cases secondary to atrial septation and/or disconnection of the superior vena cava from the right atrium. In 4 such cases, this rendered catheter mapping and ablation impossible. Indications for ablation were stated as drug-refractory tachycardia in 36 procedures (34%), lethal potential of arrhythmia in 26 (25%), impending atrial surgery in 26 (25%), patient choice in 14 (13%), and intolerable drug side effects in 3 (3%). In 5 procedures, the patient was hemodynamically unstable, with 2 procedures performed during extracorporeal membrane oxygenation. Mean procedure time was 290 ⫾ 115 minutes (range: 58 to 692), with a mean fluoroscopic time of 55.5 ⫾ 31.8 minutes (range: 11.9 to 163), mean number of RF applications of 11 ⫾ 9 (range: 1 to 62), and a mean time of RF ablation of 245 ⫾ 194 s (range: 30 to 1015 s) (Table 2).
AP-mediated tachycardias Seventy patients had a total of 110 APs. Sixty-six APs were manifest, 36 were concealed, and 8 were designated as Mahaim fibers. Multiple APs were present in 14 (20%) of these patients. Of the 110 APs, 38 were left-sided (23 free wall, 11 posteroseptal, 4 anteroseptal), and 72 right-sided (44 free wall, 20 posteroseptal, 8 anteroseptal). Acute success rate was 77% per procedure overall: 82% for left-sided APs (free wall 87%, posteroseptal 64%, anteroseptal 100%), and 70% for right-sided APs (free wall 73%, posteroseptal 68%, anteroseptal 62%) (Figure 1). The mean RF application time to success was 116 ⫾ 124 s (range: 0.5 to 541), for a mean successful lesion time of 3.2 ⫾ 3 s (range: 0.5 to 15). After a mean follow-up of 44 ⫾ 35 months (range: 3 to 231), recurrence rate for successful RF ablations was 24% (11 documented tachycardias, 5 reemergence of preexcitation), with 21 repeat RF ablations needed in 19 patients (missing data for 9 patients) (Table 3). Antiarrhythmic medication was prescribed after ablation in 19/68 patients, 2 of whom had recurrence of targeted AVRT after acutely successful ablation procedures.
Population and electrophysiologic procedure characteristics (median [range])
General non-CHD population (n ⫽ 3653) (ref24) AP-mediated tachycardias (n ⫽ 91) AVNRT (n ⫽ 9) Twin AV nodes (n ⫽ 4)
Age (yr)
Weight (kg)
Fluoro time (min)
Procedure time (min)
RF applications
RF time (s)
13 [0.1–20.9]
50 [3.0–139]
48 [N/A]
240 [N/A]
N/A
N/A
10 [0.02–47] 14 [1.8–42] 7 [2.5–25.2]
37 [2.5–108] 59 [26–106] 22 [12–78]
47 [12–163] 60 [27–77] 57 [51–69]
270 [58–692] 280 [120–360] 373 [240–520]
9 [1–62] 7 [4–19] 13 [5–26]
225 [9–1015] 195 [131–519] 258 [83–844]
N/A-data not available. General population includes no patients without concomitant congenital heart disease.
Chetaille et al
Ablation in Congenital Heart Disease
171 Table 4 Acute success and recurrence rates in Ebstein’s anomaly vs. patients with other forms of CHD Diagnosis
Acute Recurrence Patients Procedures success* rate**
Ebstein’s ⫹ AP 27 Other CHD ⫹ AP 43
41 51
87% 69%
29% 19%
* P ⫽ .076, **P ⫽ .554, Fisher’s exact test
Figure 1 Distribution of accessory pathways in patients with CHD and rate of acutely successful RF catheter ablation.
Acute success rate within the group of Ebstein’s anomaly (27 patients, 41 procedures) was 87%, with a recurrence rate of 29% at end of follow-up. These numbers were 69% and 19% in the other CHD group (43 patients, 51 procedures). The differences between the 2 groups were not statistically significant (Fisher’s exact test) (Table 4). Two major complications were recorded. The first occurred in a 47-year-old obese female with mild Ebstein’s anomaly and an atrial septal defect who underwent successful ablation of ectopic atrial tachycardia and antidromic reentrant tachycardia due to a Mahaim fiber. The procedure was performed with heparin anticoagulation (activated clotting time ⬎ 250 s), and the patient left the hospital taking aspirin. At home one week after procedure, she presented with a sudden onset of dyspnea followed shortly by a fatal stroke. The second major complication involved a 7-yearold boy who suffered a hemothorax after puncture of his subclavian artery. The procedure was terminated and pleural drainage placed without further complication; a subsequent ablation procedure was successful and uncomplicated. Three minor complications (1 large groin hematoma, 2 poorly tolerated induced tachycardias resulting in transient pulmonary edema and hypotension) were reported, making an overall complication rate of 5.5% procedures in the AP population.
AV nodal reentrant tachycardia Nine patients with AVNRT (age 19.6 ⫾ 14.3 years) had modification of the AV node. There were 7/9 (78%) acute
Table 3
Acute success and recurrence rates Acute Median success Recurrence follow-up Number (%) rate (%) (months [range])
AP-mediated tachycardias 110 AVNRT 9 Twin AV nodes 4
77 78 75
24 0 0
39 [0.5–123] 9 [1–40] 26 [8–26]
successes, with no recurrence at a mean follow-up of 15 ⫾ 15 months (range: 3 to 40) (Table 3). One patient is still on antiarrhythmic medications at follow-up. Follow-up data are unavailable on 2 patients. There was 1 minor complication (hypotension during tachycardia induction).
“Twin” AV nodes Four patients had “twin” AV nodes. Acute success was achieved in 3/4 (75%) patients with no recurrence at 20 ⫾ 10 months (range: 8 to 26) follow-up (Table 3). One patient is still on antiarrhythmic medication and data are missing for 1 patient at follow-up. There was 1 minor complication (groin hematoma).
Late outcomes of RF ablation Overall, at 44 ⫾ 35 months follow-up, successful ablation was achieved in 59% of procedures and 68% of patients, with 19 patients (23%) undergoing one or more repeat ablations. Twelve patients were lost at follow-up: 9 with AP-mediated tachycardias (all had acutely successful procedures), 1 with twin AV nodes (failed procedure), and 2 with AVNRT (both acutely successful procedures).
Discussion Of pediatric patients reported to the Pediatric RF Registry, 10% have associated heart disease.15 AV reciprocating tachycardias represented 55% (orthodromic reciprocating tachycardia in 46%, AVNRT in 9%) of supraventricular tachycardia mechanisms seen in these patients.14 Association between CHD and AP-mediated tachycardias are known to occur in Ebstein’s anomaly,1,2 L-transposition of the great arteries,3 and hypertrophic cardiomyopathy.4 “Twin” AV nodes, occurring in patients with heterotaxy syndromes, may cause a supraventricular tachycardia.11,16 In addition, AV reciprocating tachycardias due to APs and AV node reentry have been reported in most varieties of CHD with prevalence probably not different from that seen in the general population.5 Ablation techniques using RF current have been well described for the treatment of AP-mediated tachycardias17–20 and AVNRT,18,21 and in children generally.22–24 Previous reports of ablation in CHD have been based on
172 analysis of multicenter registry data, investigation of atrial and ventricular reentrant tachycardias, or smaller series focused on demonstration of feasibility or complex and/or unusual mechanism of AV reciprocating tachycardia.7–10,12 In comparison to these smaller studies, lower acute and chronic success rates of RF catheter ablation were observed in the current series. Our acute success rates were similar for AP-mediated tachycardias (77%), AVNRT (78%), and twin AV nodes (75%), although small numbers of the latter 2 arrhythmia substrates preclude meaningful statistical comparison. Right-sided APs were more prevalent in this population than in patients with normal anatomy, while success rate was higher in left-sided, nonseptal APs, which is in accordance with the general population.25 Over four years of follow-up, 68% of all patients with CHD selected for RF ablation for therapy of AV reciprocating tachycardia had successful treatment by this modality, with nearly one quarter requiring multiple RF procedures. Thus, the principal finding of this large, single-center study is that, while catheter ablation of AV reciprocating tachycardia is feasible in most patients with CHD, it is considerably less likely to be acutely and chronically successful than similar procedures performed in children with normal cardiac anatomy. In 20 patients (24%), all postoperative catheter access was impeded or rendered impossible by prior surgical modifications of cardiovascular anatomy and/or other iatrogenic loss of vascular access. This suggests that in infants and toddlers, the risk of early catheter ablation should be balanced against the potential future difficulties anticipated in children who will undergo multiple surgical and vascular procedures, with high likelihood of iatrogenic loss of vascular and endocardial access. Impending surgical procedure was an indication for elective RF ablation in 25% of the cases reported here. This number may increase as procedures limiting access to the endocardial surface (e.g., extracardiac Fontan procedures) are performed in younger and younger patients. Overall complication rate in this study group was 5.5%, with 1 death. Previous studies report comparable rates of morbidity and mortality: in the pediatric RF registry between 1989 and 1999, 786 patients were coded as having CHD, with a complication rate of 8% (4.2% serious complications) and 0.3% mortality.14 By comparison, 3653 RF ablation cases with normal cardiac anatomy experienced a serious complication rate of 3.2% and 0.1% mortality.24 Prior studies have observed the unusual difficulty in successful ablation of AV reciprocating tachycardias in patients with Ebstein’s anomaly.8,12,13 It could be conjectured that the relative frequency of AV reciprocating tachycardia that occurs in this anatomy might account for lower success rates in ablation in congenital heart populations. In our group, Ebstein’s anomaly was present in only a third of the patients. Although likelihood of recurrence was relatively higher in this subgroup, no differences were noted in acute success rates. Thus, the specific and well-known difficulties associated with ablation in this subgroup do not in them-
Heart Rhythm, Vol 1, No 2, July 2004 selves constitute a primary explanation for lower success rates in CHD patients as a population. It is of interest to note that the rates of acute and chronic success in this study group are similar to success rates obtained in the same institution for ablation of intra-atrial reentrant tachycardia.26 This arrhythmia has generally been considered to represent a much more difficult ablation problem, with lowered expectation of ablation success. One possible conclusion is that the substrate of CHD itself poses a considerable obstacle to successful ablative therapy, independent of the specific arrhythmia mechanism being approached. This study is limited by its retrospective design, and it summarizes clinical outcomes that were recorded over a significant period of time, during which significant modifications in the practice and technology of RF ablation have occurred. There exists a significant possibility of referral bias towards patients with more refractory tachycardia. There may also be a counterbalancing effect of operator experience, given the large patient volume of this center. Several of the patients in this report have been previously reported in other studies from this center and/or in multicenter registry reports.5,11,12,15,16
Conclusion Radiofrequency catheter ablation can be performed in patients with CHD and AV reciprocating tachycardia, with similar expectations with regard to procedural safety, but lower expectation of acute and long-term success.
References 1. Lev M, Givson S, Miller RA. Ebstein’s disease with Wolff-ParkinsonWhite syndrome. Am Heart J 1955;49:724 –741. 2. Scheibler GL, Adams P, Anderson RC. Clinical study of twenty-three cases of Ebstein’s anomaly of the tricuspid valve. Circulation 1959; 19:165–187. 3. Benson DW, Gallagher JJ, Oldham HN, Sealy WC, Sterba R, Spach MS. Corrected transposition with severe intracardiac deformities with Wolff-Parkinson-White syndrome in a child. Electrophysiologic investigation and surgical correction. Circulation 1980;61:1256 –1261. 4. Perosio AM, Suarez LD, Bunster AM, Locreille A, Apkarian OA, Vallazza MA, Foye R. Pre-excitation syndrome and hypertrophic cardiomyopathy. J Electrocardiol 1983;16:29 – 40. 5. Saul JP, Walsh EP, Triedman JK. Mechanisms and therapy of complex arrhythmias in pediatric patients. J Cardiovasc Electrophysiol 1995;6: 1129 –1148. 6. Weindling SN, Saul JP, Walsh EP. Efficacy and risks of medical therapy for supraventricular tachycardia in neonates and infants. Am Heart J 1996;131:66 –72. 7. Van Hare GF. Radiofrequency ablation of accessory pathways associated with congenital heart disease. PACE 1997;20:2077–2081. 8. Chiou CW, Chen SA, Chiang CE, Wu TJ, Tai CT, Lee SH, Cheng CC, Ueng KC, Chen CY, Wang SP. Radiofrequency catheter ablation of paroxysmal supraventricular tachycardia in patients with congenital heart disease. Intern J Cardiol 1995;50:143–151. 9. Van Hare GF, Lesh MD, Stanger P. Radiofrequency catheter ablation of supraventricular arrhythmias in patients with congenital heart dis-
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Ablation in Congenital Heart Disease
ease: results and technical considerations. J Am Coll Cardiol 1993;22: 883– 890. Hebe J, Hansen P, Ouyang F, Volkmer M, Kuck KH. Radiofrequency catheter ablation of tachycardia in patients with congenital heart disease. Pediatr Cardiol 2000;21:557–575. Levine JC, Walsh EP, Saul JP. Radiofrequency ablation of accessory pathways associated with congenital heart disease including heterotaxy syndrome. Am J Cardiol 1993;72:689 – 693. Reich JD, Auld D, Hulse E, Sullivan K, Campbell R. The pediatric radiofrequency ablation registry’s experience with Ebstein’s anomaly. J Cardiovasc Electrophysiol 1998;9:1370 –1377. Cappato R, Schlu¨ ter M, Weiss C, Antz M, Koschyk DH, Hofmann T, Kuck KH. Radiofrequency current catheter ablation of accessory atrioventricular pathways in Ebstein’s anomaly. Circulation 1996;94:376 – 383. Perry JC, Iverson P, Kugler JD. Radiofrequency catheter ablation of tachyarrhythmias in young patients with structurally abnormal heart (abstr). PACE 1996;19:579. Kugler JD, Danford DA, Deal BJ, Gillette PC, Perry JC, Silka MJ, Van Hare GF, Walsh EP. Radiofrequency catheter ablation for tachyarrhythmias in children and adolescents. N Engl J Med 1994;330:1481– 1487. Epstein MR, Saul JP, Weindling SN, Triedman JK, Walsh EP. Atroventricular reciprocating tachycardia involving twin atrioventricular nodes in patients with complex congenital heart disease. J Cardiovasc Electrophysiol 2001;12:671– 679. Jackman WM, Wang XZ, Friday KJ, Roman CA, Moulton KP, Beckman KJ, McClelland JH, Twidale N, Hazlitt HA, Prior MI. Catheter ablation of accessory atrioventricular pathways (Wolff-ParkinsonWhite syndrome) by radiofrequency current. N Engl J Med 1991;324: 1605–1611.
173 18. Calkins H, Sousa J, El-Atassi R, Rosenheck S, de Buitleir M, Kou WH, Kadish AH, Langberg JJ, Morady F. Diagnosis and cure of the Wolff-Parkinson-White syndrome or paroxysmal supraventricular tachycardias during a single electrophysiologic test. N Engl J Med 1991;324:1612–1618. 19. Bolling SF, Morady F, Calkins H, Kadish A, de Buitleir M, Langberg J, Dick M, Lupinetti FM, Bove EL. Current treatment for WolffParkinson-White syndrome: results and surgical implications. Ann Thorac Surg 1991;52:461– 468. 20. Kuck KH, Schlu¨ ter M. Single-catheter approach to radiofrequency current ablation of left-sided accessory pathways in patients with Wolff-Parkinson-White syndrome. Circulation 1991;84:2366 –2375. 21. Epstein LM, Scheinman MM, Langberg JJ, Chilson D, Goldberg HR, Griffin JC. Percutaneous catheter modification of the atrioventricular node: a potential cure for atrioventricular nodal reentrant tachycardia. Circulation 1989;80:757–768. 22. Case CL. Radiofrequency catheter ablation of arrhythmias in infants and small children. Prog Pediatr Cardiol 2000;11:77– 82. 23. Kugler JD, Danford DA, Houston KA, Felix G. Pediatric radiofrequency catheter ablation registry success, fluoroscopy time, and complication rate for supraventricular tachycardia: comparison of early and recent eras. J Cardiovasc Electrophysiol 2002;13:336 –341. 24. Kugler JD, Danford DA, Houston K, Felix G. Radiofrequency catheter ablation for paroxysmal supraventricular tachycardia in children and adolescents without structural heart disease. Am J Cardiol 1997;80: 1438 –1443. 25. Etheridge SP. Radiofrequency catheter ablation of left-sided accessory pathways in pediatric patients. Prog Pediatr Cardiol 2001;13:11–24. 26. Triedman JK, Bergau DM, Saul JP, Epstein MR, Walsh EP. Efficacy of radiofrequency ablation for control of intraatrial reentrant tachycardia in patients with congenital heart disease. J Am Coll Cardiol 1997;30:1032–1038.
www.heartrhythmjournal.com
Outcomes of radiofrequency catheter ablation of atrioventricular reciprocating tachycardia in patients with congenital heart disease Philippe Chetaille, MD,a,b Edward P. Walsh, MD,b John K. Triedman, MDb a
From the Hoˆpital d’Enfants de la Timone, Marseille, France and Children’s Hospital Boston, Boston, Massachusetts.
b
KEYWORDS Radiofrequency catheter ablation; Congenital heart disease; Supraventricular tachycardia
OBJECTIVES Assessment of clinical outcomes of catheter ablation of atrioventricular reciprocating tachycardias in patients with congenital heart disease (CHD). BACKGROUND Atrioventricular reciprocating tachycardias occur in patients with CHD and may be poorly tolerated. METHODS Retrospective review of all 105 such ablations in 83 patients performed between 03/90 and 02/02 at one institution. RESULTS The dominant arrhythmia mechanism was accessory pathway (70 patients, 84%), and the most common indications were drug-refractory tachycardia, life-threatening arrhythmia, and elective presurgical ablation. Congenital heart disease diagnoses were diverse, with one third of patients having Ebstein’s anomaly. Twenty patients (24%) had catheter access limited by prior surgeries or occluded vascular access. Of 109 accessory pathways (APs), 74 (68%) were manifestly preexcited, and 71 (65%) were located on the right atrioventricular groove. Fourteen patients (20%) had multiple pathways. There were 2 major complications (1 death, 1 hemorrhage), and 3 minor complications (5.5% of procedures). Acute success rate was 80% per procedure, 82% for left- and 70% for right-sided APs. Acute success rates for patients with Ebstein’s anomaly were similar to patients with other CHD diagnoses, but Ebstein’s patients were more likely to have recurrence. At 44 ⫾ 35 months follow-up, successful ablation was achieved in 59% of procedures and 68% of patients, with 19 patients (23%) undergoing one or more repeat ablations. CONCLUSIONS Compared to patients with normal cardiac anatomy, patients with CHD of all varieties have lower rates of acute and long-term success for ablation for atrioventricular reciprocating tachycardias. © 2004 Heart Rhythm Society. All rights reserved.
Supraventricular tachycardias may occur in the setting of structural congenital heart disease (CHD) and may compliDr. Chetaille was supported in part by grants from the Agence pour le De´veloppement de la Recherche Me´dicale, Assistance Publique des Hoˆpitaux de Marseille, France and the Association Re´gionale de Cardiologie de Provence, France. Address reprint requests and correspondence: John K. Triedman, MD, 300 Longwood Ave., Boston, Massachusetts 02115. E-mail address: [email protected]. (Received January 29, 2004; accepted March 16, 2004.)
cate their management. Associations between several congenital malformations and accessory pathway (AP)-mediated tachycardias are well described,1– 4 and atrioventricular (AV) reciprocating tachycardias due to AP and AV node reentry have been reported in most other varieties of congenital heart disease with prevalence similar to that seen in the general population.5 Underlying hemodynamic compromise results in tachycardia being poorly tolerated in many of these patients,6 and may also complicate management with antiarrhythmic medications and during perioperative
1547-5271/$ -see front matter © 2004 Heart Rhythm Society. All rights reserved. doi:10.1016/j.hrthm.2004.03.064
Chetaille et al
Ablation in Congenital Heart Disease
periods. Radiofrequency (RF) catheter ablation has been demonstrated to be feasible in this patient population, but available data on outcomes are based either on small series7–11 or multicenter registry analysis.12–14 In this study, we retrospectively analyzed clinical indications and outcomes in a large series of patients with CHD treated at a single institution with RF catheter ablation for AV reciprocating tachycardias.
Methods
169 Recurrence was defined as documented supraventricular tachycardia or reemergence of preexcitation within the successfully ablated population. Undocumented arrhythmia symptoms or performance of another ablation for tachycardia of proven distinct mechanism were not classified as recurrences. Patients who were lost to follow-up were excluded for statistical analysis of recurrence rates. Minor complication was defined as complication that was transient and did not require new therapy. Major complication was defined as death related to procedure or any complication that had significant therapeutic implication.
Study patients
Ablation protocol
All patients with a diagnosis of structural CHD referred to Children’s Hospital Boston for RF catheter ablation of AV reciprocating tachycardia between March 1990 and March 2002 were included in the study group. Complete case identification was ensured by clinical and billing database searches and manual logbook review. For each patient, electrophysiologic data were reviewed to determine acute clinical outcome, and clinical notes from local and referring cardiologists used to ascertain outcome on most recent follow-up evaluation. Follow-up duration was defined as time between first procedure and last clinic visit. The Committee on Clinical Investigation of Children’s Hospital Boston approved the study.
Procedures were usually performed under general anesthesia or, infrequently, conscious sedation. Vascular access for ablation was determined to some extent by patient size and intracardiac anatomy, and typically obtained by femoral veins (87% of cases), with other access used as necessary (internal jugular vein 4%, subclavian vein 3%, femoral artery 6%). Although most patients had an identifiable coronary sinus, its location and course were sometimes aberrant and/or inaccessible, especially in patients who had undergone surgeries involving atrial baffling. Occasionally, an esophageal electrode catheter was used for left atrial timing and/or pacing. Because of associated congenital diagnoses, complete hemodynamic and angiographic studies were performed on the majority of patients prior to electrophysiologic study. Access to the AP was antegrade in 67% of cases, transseptal in 27%, and retrograde in 6% of cases. Standard approaches to substrate diagnosis were applied, including atrial and ventricular extrastimulation protocols, placement of critically timed ventricular extrastimuli, and diagnostic use of isoproterenol and adenosine. After identification of targeted arrhythmia substrates, RF lesions were applied using electrophysiology catheters ranging in diameter from 5 to 7 F and with tip size 4 mm. Rarely, 8-mm-tip or internally cooled ablation catheters were employed in the event of repeated failures of ablation using a 4-mm-tip catheter. RF energy was generated using either a voltage-controlled (Radionics RFG-3C, Radionics, Inc., Burlington, MA) or a temperature-controlled (Atakr, Medtronic Cardiorhythm, San Jose, CA) RF generator. Antegrade and retrograde conduction properties of ablated APs were immediately tested, and attempts made to reinduce the ablated tachycardia using decremental atrial and ventricular extrastimulation protocols. Isoproterenol was routinely used to increase the sensitivity of postablation testing. When additional tachycardia mechanisms deemed to be of potential clinical relevance were identified, mapping and ablation procedures were repeated.
Anatomical classification Anatomical diagnoses were determined from echocardiographic and angiographic data. Patients with isolated findings limited to patent foramen ovale, hemodynamically trivial patent ductus arteriosus, or mitral valve prolapse without significant mitral valve regurgitation were excluded from review. Single ventricle refers to all patients with univentricular physiology and includes all anatomic categories with this physiology. Heterotaxy refers to patients with mixed thoracic and abdominal situs, with anomalies of venous connections to the heart and major intra-cardiac defects in most cases.
Outcome classification Acute success for AP ablation was defined as demonstration of antegrade and retrograde block of at least one targeted pathway and absence of inducible tachycardia after ablation. Failed ablation was defined as continued inducibility of tachycardia, and indeterminate outcome was defined as absence of inducible tachycardia but with failure to demonstrate antegrade and/or retrograde conduction block. Failed ablation and indeterminate outcomes were both counted as failures for statistical purposes. Similarly, acutely successful ablation of AV nodal reentrant tachycardia (AVNRT) and twin AV nodes was defined as absence of dual AV nodal pathway physiology after ablation and noninducibility of tachycardia.
Statistical analysis Aggregate data are presented as mean ⫾ standard deviation or median (range) as appropriate. Univariate analyses
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Table 1
CHD categories Number (% of population)
CHD Ebstein’s anomaly Single ventricle Atrial septal defect CAVC L-TGA Tetralogy of Fallot Anomalous pulmonary venous connection HCM Other (includes DORV, ventricular septal defect, mital and aortic valve disease, cor triatriatum)
28 (34%) 17 (20%) 8 (9%) 4 (5%) 4 (5%) 3 (4%) 3 (4%) 3 (4%)
13 (15%)
CAVC ⫽ Complete atrioventricular canal; CHD ⫽ Congenital heart disease; DORV ⫽ Double outlet right ventricle; HCM ⫽ Hypertrophic cardiomyopathy; L-TGA ⫽ L-transposition of great arteries. Note that patients may be classified in more than one category.
were performed using chi-square analyses for frequency and t-test for differences in normally distributed means. Significance differences have a P-value of ⱕ .05.
Results During the study period, 105 procedures were performed in 83 patients, with 26 patients undergoing 2 or more ablation procedures. Two additional patients undergoing 3 procedures were excluded from analysis due to insufficient information. The mean age was 11.7 ⫾ 10.3 years (range: 0.2 to 47.2 years), and mean weight was 39.1 ⫾ 27.2 kg (range: 2.5 to 108 kg). Twelve procedures were performed in patients less than or equal to 12 months of age; indications for ablation in these cases were: apparent life-threatening event possibly associated with supraventricular tachycardia (SVT), drug-refractory SVT, and impending surgical atrial septation. Anatomical diagnoses were diverse, with some patients having multiple CHD diagnoses, with the largest single category being Ebstein’s anomaly (28 patients, 34%) (Table 1). Eighteen patients (22%) had AV discordance, and 7 (9%) had heterotaxy syndrome. A mean of 0.8 anti-
Table 2
arrhythmic medications (range: 0 to 2) had been prescribed prior to referral for ablation. Prior cardiac surgery had been performed in 61 patients (74%), and was considered to limit catheter access in 20 (24%), in most cases secondary to atrial septation and/or disconnection of the superior vena cava from the right atrium. In 4 such cases, this rendered catheter mapping and ablation impossible. Indications for ablation were stated as drug-refractory tachycardia in 36 procedures (34%), lethal potential of arrhythmia in 26 (25%), impending atrial surgery in 26 (25%), patient choice in 14 (13%), and intolerable drug side effects in 3 (3%). In 5 procedures, the patient was hemodynamically unstable, with 2 procedures performed during extracorporeal membrane oxygenation. Mean procedure time was 290 ⫾ 115 minutes (range: 58 to 692), with a mean fluoroscopic time of 55.5 ⫾ 31.8 minutes (range: 11.9 to 163), mean number of RF applications of 11 ⫾ 9 (range: 1 to 62), and a mean time of RF ablation of 245 ⫾ 194 s (range: 30 to 1015 s) (Table 2).
AP-mediated tachycardias Seventy patients had a total of 110 APs. Sixty-six APs were manifest, 36 were concealed, and 8 were designated as Mahaim fibers. Multiple APs were present in 14 (20%) of these patients. Of the 110 APs, 38 were left-sided (23 free wall, 11 posteroseptal, 4 anteroseptal), and 72 right-sided (44 free wall, 20 posteroseptal, 8 anteroseptal). Acute success rate was 77% per procedure overall: 82% for left-sided APs (free wall 87%, posteroseptal 64%, anteroseptal 100%), and 70% for right-sided APs (free wall 73%, posteroseptal 68%, anteroseptal 62%) (Figure 1). The mean RF application time to success was 116 ⫾ 124 s (range: 0.5 to 541), for a mean successful lesion time of 3.2 ⫾ 3 s (range: 0.5 to 15). After a mean follow-up of 44 ⫾ 35 months (range: 3 to 231), recurrence rate for successful RF ablations was 24% (11 documented tachycardias, 5 reemergence of preexcitation), with 21 repeat RF ablations needed in 19 patients (missing data for 9 patients) (Table 3). Antiarrhythmic medication was prescribed after ablation in 19/68 patients, 2 of whom had recurrence of targeted AVRT after acutely successful ablation procedures.
Population and electrophysiologic procedure characteristics (median [range])
General non-CHD population (n ⫽ 3653) (ref24) AP-mediated tachycardias (n ⫽ 91) AVNRT (n ⫽ 9) Twin AV nodes (n ⫽ 4)
Age (yr)
Weight (kg)
Fluoro time (min)
Procedure time (min)
RF applications
RF time (s)
13 [0.1–20.9]
50 [3.0–139]
48 [N/A]
240 [N/A]
N/A
N/A
10 [0.02–47] 14 [1.8–42] 7 [2.5–25.2]
37 [2.5–108] 59 [26–106] 22 [12–78]
47 [12–163] 60 [27–77] 57 [51–69]
270 [58–692] 280 [120–360] 373 [240–520]
9 [1–62] 7 [4–19] 13 [5–26]
225 [9–1015] 195 [131–519] 258 [83–844]
N/A-data not available. General population includes no patients without concomitant congenital heart disease.
Chetaille et al
Ablation in Congenital Heart Disease
171 Table 4 Acute success and recurrence rates in Ebstein’s anomaly vs. patients with other forms of CHD Diagnosis
Acute Recurrence Patients Procedures success* rate**
Ebstein’s ⫹ AP 27 Other CHD ⫹ AP 43
41 51
87% 69%
29% 19%
* P ⫽ .076, **P ⫽ .554, Fisher’s exact test
Figure 1 Distribution of accessory pathways in patients with CHD and rate of acutely successful RF catheter ablation.
Acute success rate within the group of Ebstein’s anomaly (27 patients, 41 procedures) was 87%, with a recurrence rate of 29% at end of follow-up. These numbers were 69% and 19% in the other CHD group (43 patients, 51 procedures). The differences between the 2 groups were not statistically significant (Fisher’s exact test) (Table 4). Two major complications were recorded. The first occurred in a 47-year-old obese female with mild Ebstein’s anomaly and an atrial septal defect who underwent successful ablation of ectopic atrial tachycardia and antidromic reentrant tachycardia due to a Mahaim fiber. The procedure was performed with heparin anticoagulation (activated clotting time ⬎ 250 s), and the patient left the hospital taking aspirin. At home one week after procedure, she presented with a sudden onset of dyspnea followed shortly by a fatal stroke. The second major complication involved a 7-yearold boy who suffered a hemothorax after puncture of his subclavian artery. The procedure was terminated and pleural drainage placed without further complication; a subsequent ablation procedure was successful and uncomplicated. Three minor complications (1 large groin hematoma, 2 poorly tolerated induced tachycardias resulting in transient pulmonary edema and hypotension) were reported, making an overall complication rate of 5.5% procedures in the AP population.
AV nodal reentrant tachycardia Nine patients with AVNRT (age 19.6 ⫾ 14.3 years) had modification of the AV node. There were 7/9 (78%) acute
Table 3
Acute success and recurrence rates Acute Median success Recurrence follow-up Number (%) rate (%) (months [range])
AP-mediated tachycardias 110 AVNRT 9 Twin AV nodes 4
77 78 75
24 0 0
39 [0.5–123] 9 [1–40] 26 [8–26]
successes, with no recurrence at a mean follow-up of 15 ⫾ 15 months (range: 3 to 40) (Table 3). One patient is still on antiarrhythmic medications at follow-up. Follow-up data are unavailable on 2 patients. There was 1 minor complication (hypotension during tachycardia induction).
“Twin” AV nodes Four patients had “twin” AV nodes. Acute success was achieved in 3/4 (75%) patients with no recurrence at 20 ⫾ 10 months (range: 8 to 26) follow-up (Table 3). One patient is still on antiarrhythmic medication and data are missing for 1 patient at follow-up. There was 1 minor complication (groin hematoma).
Late outcomes of RF ablation Overall, at 44 ⫾ 35 months follow-up, successful ablation was achieved in 59% of procedures and 68% of patients, with 19 patients (23%) undergoing one or more repeat ablations. Twelve patients were lost at follow-up: 9 with AP-mediated tachycardias (all had acutely successful procedures), 1 with twin AV nodes (failed procedure), and 2 with AVNRT (both acutely successful procedures).
Discussion Of pediatric patients reported to the Pediatric RF Registry, 10% have associated heart disease.15 AV reciprocating tachycardias represented 55% (orthodromic reciprocating tachycardia in 46%, AVNRT in 9%) of supraventricular tachycardia mechanisms seen in these patients.14 Association between CHD and AP-mediated tachycardias are known to occur in Ebstein’s anomaly,1,2 L-transposition of the great arteries,3 and hypertrophic cardiomyopathy.4 “Twin” AV nodes, occurring in patients with heterotaxy syndromes, may cause a supraventricular tachycardia.11,16 In addition, AV reciprocating tachycardias due to APs and AV node reentry have been reported in most varieties of CHD with prevalence probably not different from that seen in the general population.5 Ablation techniques using RF current have been well described for the treatment of AP-mediated tachycardias17–20 and AVNRT,18,21 and in children generally.22–24 Previous reports of ablation in CHD have been based on
172 analysis of multicenter registry data, investigation of atrial and ventricular reentrant tachycardias, or smaller series focused on demonstration of feasibility or complex and/or unusual mechanism of AV reciprocating tachycardia.7–10,12 In comparison to these smaller studies, lower acute and chronic success rates of RF catheter ablation were observed in the current series. Our acute success rates were similar for AP-mediated tachycardias (77%), AVNRT (78%), and twin AV nodes (75%), although small numbers of the latter 2 arrhythmia substrates preclude meaningful statistical comparison. Right-sided APs were more prevalent in this population than in patients with normal anatomy, while success rate was higher in left-sided, nonseptal APs, which is in accordance with the general population.25 Over four years of follow-up, 68% of all patients with CHD selected for RF ablation for therapy of AV reciprocating tachycardia had successful treatment by this modality, with nearly one quarter requiring multiple RF procedures. Thus, the principal finding of this large, single-center study is that, while catheter ablation of AV reciprocating tachycardia is feasible in most patients with CHD, it is considerably less likely to be acutely and chronically successful than similar procedures performed in children with normal cardiac anatomy. In 20 patients (24%), all postoperative catheter access was impeded or rendered impossible by prior surgical modifications of cardiovascular anatomy and/or other iatrogenic loss of vascular access. This suggests that in infants and toddlers, the risk of early catheter ablation should be balanced against the potential future difficulties anticipated in children who will undergo multiple surgical and vascular procedures, with high likelihood of iatrogenic loss of vascular and endocardial access. Impending surgical procedure was an indication for elective RF ablation in 25% of the cases reported here. This number may increase as procedures limiting access to the endocardial surface (e.g., extracardiac Fontan procedures) are performed in younger and younger patients. Overall complication rate in this study group was 5.5%, with 1 death. Previous studies report comparable rates of morbidity and mortality: in the pediatric RF registry between 1989 and 1999, 786 patients were coded as having CHD, with a complication rate of 8% (4.2% serious complications) and 0.3% mortality.14 By comparison, 3653 RF ablation cases with normal cardiac anatomy experienced a serious complication rate of 3.2% and 0.1% mortality.24 Prior studies have observed the unusual difficulty in successful ablation of AV reciprocating tachycardias in patients with Ebstein’s anomaly.8,12,13 It could be conjectured that the relative frequency of AV reciprocating tachycardia that occurs in this anatomy might account for lower success rates in ablation in congenital heart populations. In our group, Ebstein’s anomaly was present in only a third of the patients. Although likelihood of recurrence was relatively higher in this subgroup, no differences were noted in acute success rates. Thus, the specific and well-known difficulties associated with ablation in this subgroup do not in them-
Heart Rhythm, Vol 1, No 2, July 2004 selves constitute a primary explanation for lower success rates in CHD patients as a population. It is of interest to note that the rates of acute and chronic success in this study group are similar to success rates obtained in the same institution for ablation of intra-atrial reentrant tachycardia.26 This arrhythmia has generally been considered to represent a much more difficult ablation problem, with lowered expectation of ablation success. One possible conclusion is that the substrate of CHD itself poses a considerable obstacle to successful ablative therapy, independent of the specific arrhythmia mechanism being approached. This study is limited by its retrospective design, and it summarizes clinical outcomes that were recorded over a significant period of time, during which significant modifications in the practice and technology of RF ablation have occurred. There exists a significant possibility of referral bias towards patients with more refractory tachycardia. There may also be a counterbalancing effect of operator experience, given the large patient volume of this center. Several of the patients in this report have been previously reported in other studies from this center and/or in multicenter registry reports.5,11,12,15,16
Conclusion Radiofrequency catheter ablation can be performed in patients with CHD and AV reciprocating tachycardia, with similar expectations with regard to procedural safety, but lower expectation of acute and long-term success.
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