|
|
|
Indian Pediatr 2020;57:1127-1130 |
 |
Arrhythmia in Children
and Adolescents and Outcome of Radiofrequency Ablation for
Tachyarrhythmias - A Single Center Experience Over 16 Years
|
|
Debabrata Bera 1, Vadivelu
Ramalingam1, Chetan Rathi2,
Rajeev Sharma1, Neeta
Bachani2 and
Yash Lokhandwala1
From Departments of 1Electrophysiology and 2Cardiology, Holy Family
Hospital, Mumbai, India.
Correspondence to: Dr Debabrata Bera, Holy Family Hospital, Hill
Road, Bandra(West), Mumbai 400050,India.
Email:
[email protected]
Submitted: October 14, 2019;
Initial review: November 20, 2019;
Accepted: April 9, 2020.
Published online: June 12, 2020;
PII:S097475591600200
|
Objectives: Radiofrequency (RF) ablation for
tachycardia in children poses challenges in view of slender veins and
delicate cardiac structures in close proximity. Methods: We
reviewed hospital records for patients below 18 years,who underwent RF
ablation from August, 2001 to February, 2017 at a single hospital.
Results: Among 214 patients (134 males, age12.5 (4.6) years), there
were 221 tachycardia substrates: accessory pathways in 85 patients
(39%), AV nodal re-entrant tachycardia in 79 patients (36%), ventricular
tachycardia in 28 patients (13%) and atrial tachycardia in 21 patients
(9.6%).The overall success rate of RF ablation was 95% (204/214).
Success rate in those younger than 6 years was similar to those in older
age groups.There were no major complication. Conclusion: RF
ablation below 18 years of age has a high success rates and low
complications.
Keywords: Catheter ablation, Management, Outcome,
Supraventricular tachycardia.
|
|
C atheter ablation in
children using radio-frequency (RF) energy has been in vogue
since 1989 [1]. Radiofrequency ablation ensures a permanent cure
of arrhythmias and hence, is the preferred treatment in the vast
majority. Previous registries have demonstrated that RF ablation
can safely and effectively be performed in children [2,3].
However, patients weighing less than 15 kg have been identified
as being at greater risk for complications [2,3]. Though medical
therapy is an alternative option, it has its own limitations
[5]. The experience from India on RF ablation is also limited
[4], due to a lack of wide-spread availability, lack of
expertise, and fear of complications in children, though rare
[6].
We have been using conventional RF ablation
techniques in the pediatric age group since the last two
decades. We conducted a retrospective study of patients aged up
to 18 years and analyzed them for the tachycardia substrates,
success and complications.
METHODS
The patients were categorized into three
groups according to age: Groups A (younger than six year), B
(aged 6-12 years) and C (older than 12 years). General
anesthesia was required for the procedure for majority of
children in Groups A and B; midazolam, propofol, fentanyl and
sevoflurane were the drugs used. For Group C, local anesthesia
and sedation were used.
All anti-arrhythmic drugs were suspended for
a duration of at least four half-lives before the procedure. For
AVNRT (Atrioventricular nodal re-entrant tachy-cardia) and
right-sided accessory pathways (APs), three venous punctures
were sufficient – for coronary sinus (CS), His bundle and a
roving catheter. For left sided APs, two femoral venous accesses
and one femoral arterial route were employed. The sheaths used
ranged from 4F to 7F caliber. Unfractionated heparin was used
for all cases (50 units/ kg for venous route and 100 units/kg
for arterial route).
When the arrhythmia was not induced at
baseline, intravenous isoprenaline was administered (1-2
µg/min). Atropine (according to bodyweight) was used when
isoprenaline failed. Fluoroscopy time and procedure time were
noted. The RF energy output, length of application and
temperature were individually titrated. After ablation, 30-45
minute waiting period was kept along with isoprenaline and
atropine for re-induction.
Acute success of RF ablation was defined as
failure to induce causal arrhythmia after application of
adequate number of RF energies. Failure was defined when
tachy-cardia remained inducible at the end of the procedure.
There were two subsets, viz. unable to ablate the
tachycardia source/circuit, or unable to deliver RF energy due
to apprehension of complication or due to mechanical stunning of
the pathway. Relapses/recurrence was defined as recurrence of
same clinical arrhythmia after acute success of RF ablation.
Follow-up was done by reviewing the patients’
medical records, outpatient visits and telephonic conversation.
Follow-up period varied from 2-16 years.
Statistical analyses: The SPSS software
was used for database organization and statistical calculations.
The discrete variables were compared using Chi-square test,
considering P value below 0.05 as significant.
RESULTS
A total of 2980 cases underwent the procedure
during study period – 229 (8%) were performed in patients aged
younger than 18 years [mean (SD) age, 12.5 (4.6) year]. In 11
patients the data was incomplete; and another 4 patients did not
have inducible tachycardia.Finally, data of 214 children (62%
males) undergoing RF ablation were analyzed for this study.
These 214 patients had a total of 211
arrhythmia substrates. The commonest tachycardias found were APs
in 85 (39 %) and AVNRT in 79 (36 %) patients. The most common
arrhythmia with APs was orthodromic atrio ventricular re-entrant
tachycardia (AVRT) followed by antidromic tachycardia (ADT) and
pre-excited atrial fibrillation. Ventricular tachycardia was
found in 28 patients (13 %), and atrial tachycardia (AT) in 21
patients (9.6%). Three patients had automatic junctional
tachy-cardia and one patient had atrial flutter (previous
surgery for atrial septal defect). Four patients had multiple
tachy-cardia mechanisms and three patients had multiple APs.
We categorized them age-wise into three
subgroups (Table I). In younger children, AP was
the most common mechanism, but above 12 years, AVNRT emerged as
the most common tachycardia mechanism. Fascicular VT was by far
commoner in Group C. Among the 85 patients with APs, we detected
89 APs; of them there were nine right free wall Mahaim-like
(atrio-fascicular) APs with antidromic tachycardia. Other than
these, only two other patients had antidromic tachycardia, one
of whom also had associated orthodromic AVRT. The left lateral
location was the commonest (31/89, 35%). Left sided APs were
more common in concealed APs (18/29, 62%) than in WPW group
(13/60, 21%, P<0.001).
Table I Tachycardia Substrates in Children Undergoing Radiofrequency Ablation (N=211)*
|
≤6y
|
7-12 y |
13-18 y |
|
(n=33) |
(n=53) |
( n=135) |
| Males |
18 |
32 |
84 |
| LVEF, %# |
70 (9) |
67 (9) |
65 (10) |
| Upfront ablation |
|
|
|
| Parental preference |
1 |
5 |
22 |
|
Tachycardiomyopathy |
1 |
1 |
2 |
| AVNRT |
8 |
22 |
49 |
| Manifest AP (WPW) |
14 |
15 |
31 |
| Concealed AP |
2 |
11 |
16 |
| Atrial tachycardia |
5 |
5 |
11 |
| Fascicular VT |
1 |
0 |
17 |
| Outflow VT |
3 |
0 |
7 |
| Miscellaneous |
0 |
0 |
4 |
|
*211 substrates in 214 children; #mean (SD); LVEF:
Left ventricular ejection fraction; AVNRT:
Atrioventricular nodal reentrant tachycardia; WPW:
Wolff-Parkinson-White syndrome, AP: Accessory pathway;
VT: Ventricular tachycardia. |
The overall immediate success rate (Table
II) was 95% (204/214). For AVNRT, 98.7% (78/79) were
ablated by slow pathway modification. Among the APs, immediate
success rate was 96.4% (82/85); failure was most commonly seen
in Ebstein anomaly and with Mahaim-like pathways (Web Table
I).The success rates in the three groups were similar.
There were no major or minor complication. The recurrence rate
was 2.9 % (6/205); 2 had AVNRT, 3 had APs and 1 had AT.
Table II Success Rate of Radiofrequency Ablation in Children With Tachyarrhythmia
|
Total |
Success |
Fluoroscopy |
Mean procedure
|
No. of RF |
Maximum |
|
|
|
time (min)* |
time (min) |
lesions* |
temperature (°C)
|
| AVNRT |
79 |
78 |
10.9 (5.9) |
78 |
4.7 (2.5) |
60 |
| Accessory pathway (AVRT) |
85 |
82 |
14.6 (7.1) |
90 |
5.1 (3.3) |
55-60 |
| Atrial tachycardia |
21 |
19 |
19.3 (10.2) |
117 |
4.3 (2.0) |
50-60 |
| Outflow tract VT |
10 |
10 |
17.5 (13.3) |
103 |
5.9 (3.1) |
60 |
| Fascicular VT |
18 |
15 |
21.1 (11.1) |
130 |
6.5 (2.5) |
50-60 |
| Miscellaneous |
4 |
3 |
15 (7.2) |
90 |
3.5 (2.2) |
60 |
| *Values are expressed
as mean (SD); AVNRT: Atrioventricular nodal re-entrant
tachycardia; VT: Ventricular tachycardia. |
We sub-categorized those who had prolonged
procedures, arbitrarily defined more than two hours. There were
seven such patients; three had atrial tachycardia, three had APs
and one had VT. Five of them required left sided ablation; all
these procedures were finally successful.
Among patients undergoing the procedures, six
had congenital heart disease (three had atrial septal defect,
two had Ebstein’s anomaly and one had ventricular septal
defect). Four more patients had tachycardiomyopathy, among whom
three had incessant AT.
DISCUSSION
We found AVRT to be the most common
tachycardia below six years; above this age, AVNRT and AVRT were
comparable.This is in contrast to older studies [6], which found
that accessory pathway was the most prevalent finding between
age range of 2-18 years, with AVRT in 65%, AVNRT in 30%,
ventricular tachycardia in 4%, and atrial tachycardia in 0.7%.
Previous report shave demonstrated that RF
ablation can safely and effectively be performed in pediatric
patients [2-4,6]. After 1-16 year follow up, the overall success
rate was also higher than older studies [1]. With the advent of
cryoablation, studies revealed, AV block was less with
cryoablation, though recurrence was signi-ficantly higher [7].
We have performed only conventional RF for all age groups as
cryoablation was unavailable at our center. Van Hare, et al.
[1] reported a success rate of 95.7% with RF ablation in AVRT
and AVNRT in pediatric patients. Simao, et al. [8]
reported slightly lower success rate of 91.7% in AVNRT and 83.5%
for APs. Our study is in concordance with these previous results
[2-6]. Our study revealed better immediate success rate of 95%
and recur-rence rate of only 2.9%. After successful ablation we
could withdraw anti-arrhythmic drugs and the majority remained
asymptomatic without recurrence.
In our cohort, infants were few and hence we
did not compare or analyze the results separately. A unique
finding in our study was higher incidence of Mahaim
(atrio-fascicular) pathways (9/89, 10%). Compared to reports of
only 3% of accessory pathways [9]. Another unusual finding in
our study was that idiopathic VT comprised a significant
proportion (12.9 % of all tachycardias), where we had a good
success rate (25/28, 89%). A study [10] comparing RF ablation in
neonates and children between 1 and 18 months of age, found that
neonates had significantly higher structural heart disease and
yet the success rate and complications were surprisingly similar
in both subsets. The comparable success rates in our cohort
could partially be due to the fact that ablations in smaller
children are more likely to be attempted by more experienced
pediatric electro-physiologists and experience has been shown to
be an important factor in successful pediatric RF ablation
procedures [11].
This was a hospital-based retrospective
analysis and suffers from the risk of bias and lack of
generalizability. Infants and very small children were avoided
unless pressing indications, hence these were few subjects in
that age range. We did not have cryoablation, hence comparison
was not possible between RF and cryoablation.
We believe RF ablation can be considered for
pediatric arrhythmias, especially when they are recurrent and in
children above 5 years of age. Whether RF ablation can be a
primary treatment modality for young children is still a
debatable issue,this can perhaps be addressed by more data from
other Indian centers.
Ethical clearance: Institutional ethical
committee of Holy Family Hospital; ECR/196/INST/MH/2013/RR-16,
dated September 14, 2019.
Contributors: DB: analysed data and
drafted the manuscript; VV: collection of data, designing study;
CR: manuscript scrutiny and helped in data analysis; RS: helped
in writing the manuscript and develop images; NB: performed
echocardiography for majority of the patients and helped in data
analysis; YL: concept of the study, supervised cognitive and
behavioral assessments, supervised manuscript preparation.
Funding: None; Competing interest:
None stated.
| |
|
WHAT THIS STUDY ADDS?
• Ablation in children using conventional
radiofreauency energy was safe and effective, with
similar success rate among those younger or older than
six years.
|
REFERENCES
1. Van Hare GF, Lesh MD, Scheinman M,
Langberg JJ. Percutaneous radiofrequency catheter ablation for
supra-ventricular arrhythmias in children. J Am Coll Cardiol.
1991;17:1613-20.
2. Kugler JD, Danford DA, Deal BJ, Gillette
PC, Perry JC, Silka MJ, et al. Radiofrequency catheter
ablation for tachyarrhythmias in children and adolescents. New
England J Med. 1994;330:1481-7.
3. Kugler JD, Danford DA, Houston K, Felix G.
Radio-frequency catheter ablation for paroxysmal
supra-ventricular tachycardia in children and adolescents
without structural heart disease. Am J Cardiol. 1997;804:
1438-43.
4. Vora A, Lokhandwala Y, Sheth C, Dalvi B.
Radiofrequency ablation in an infant with recurrent
supraventricular tachy-cardia and cyanosis. Ann Pediatr
Cardio.2009; 2:156-8.
5. Maragnès P, Tipple M, Fournier A.
Effectiveness of oral sotalol for treatment of pediatric
arrhythmias. Am J Cardiol. 1992;69:751-54.
6. Kim YH, Park H-S, Hyun MC, Kim Y-N.
Pediatric tachyarrhythmia and radiofrequency catheter ablation:
Results from 1993 to 2011. Korean Circulation J. 2012;42:
735-40.
7. Avari J, Jay K, Rhee E. Experience and
results during transition from radiofrequency ablation to
cryoablation for treatment of pediatric atrioventricular nodal
reentrant tachy- cardia. Pacing Clinical
Electrophysiol.2008;31:454-60.
8. Simao MF, Rios MN, Leiria TL, Kruse ML,
Pires LM, Sant Anna RT, et al. Electrophysiological
studies and radio-frequency ablations in children and
adolescents with arrhythmia. Arq Bras Cardiol.2015;104:53-7.
9. Miller JM, Olgin JE. Catheter ablation of
free-wall accessory pathways and ‘Mahaim’ fibers. In:
Zipes DP, Haissaguere M, editors. Catheter ablation of cardiac
arrhythmias. 2nd edition. Armonk, NY: Futura, 2002 :277-303.
10. Blaufox AD, Felix GL, Saul JP. Pediatric
catheter ablation registry radiofrequency catheter ablation in
infants and dd18 months old: When is it done and how do they
fare? Short-term data from the pediatric ablation registry.
Circulation. 2001; 104:2803-8.
11. Danford D, Kugler J, Deal B, Case C,
Friedman R, Saul J, et al. The learning curve for
radiofrequency ablation of tachyarrhythmias in pediatric
patients. Am J Cardiol. 1995;75:587-90.
|
|
|
 |
|
