Download ECTOPIC ATRIAL TACHYCARDIA IN CHILDREN

J.N. Wang, J.M. Wu, Y.C. Tsai, et al
ECTOPIC ATRIAL TACHYCARDIA IN CHILDREN
Jieh-Neng Wang, Jing-Ming Wu, Yu-Chien Tsai,1 and Chia-Shiang Lin
Background and purpose: Ectopic atrial tachycardia (EAT) is an unusual and potentially
risky arrhythmia that can result in left ventricular dysfunction if not properly
managed. In adults, EAT is mainly caused by diseased atrial myocardium and responds
poorly to antiarrhythmic drugs. The characteristics of EAT in children might be
different from those in adults because of their immature myocardium and the
different electrophysiologic characteristics of their conduction tissue. We examined
the natural history and treatment of EAT in children.
Methods and results: From June 1990 through June 1999, 24 children (8 girls and
16 boys; median age 4 mo [1 d–10 yr]) were admitted to our hospital with a diagnosis
of EAT. Fifteen had healthy hearts, six had congenital heart disease, one had
myocarditis, one had bronchopulmonary dysplasia with severe pulmonary
hypertension, and one had hypertrophic cardiomyopathy. Thirteen patients presented with congestive heart failure. Only four patients had symptoms of prodromal
airway infection. The maximum atrial rate was 244 ± 66 beats per minute. Atrioventricular block was documented at least once during tachycardia in 10 patients.
Warm-up or cool-down phenomenon was seen at the initiation or termination of
tachycardia in thirteen patients. Primary pharmacologic treatment was attempted
in all patients. EAT was initially controlled in all patients using digoxin plus propranolol (18 patients), propranolol only (4), or digoxin plus procainamide (2). EAT
was controlled using medication in 22 patients. Fifteen patients had sinus rhythm
but did not receive medication for 39 ± 25 months. Two patients died of uncontrolled
arrhythmia, and two of underlying disease. Recurrence was seen within 3 months
after initial therapy in five patients. Surgery was performed to correct the underlying
heart disease in three patients with frequently recurring EAT, all of whom remained
tachycardia-free after surgery, without pharmacologic treatment. The spontaneous
remission rate was 75% (18/24).
Conclusion: EAT in children without underlying heart disease can be effectively treated
using antiarrhythmic drugs. Spontaneous resolution of EAT after medication in
children was frequent (75%) in this series. The results of this study suggest that
a step-wise approach using digoxin, a beta-blocker, and a class I antiarrhythmic drug
may be the most effective treatment for EAT.
Ectopic atrial tachycardia (EAT) is an uncommon
arrhythmia that occurs mostly in young children [1, 2].
Timely recognition of EAT is important because it can
cause tachycardia-induced cardiomyopathy [3, 4].
Despite the fact that the clinical and electrophysiologic
features of this arrhythmia have been extensively investigated [5, 6], little is known about the natural history
of the disease, particularly in terms of spontaneous
remission [7, 8].
(J Formos Med Assoc
2000;99:766–70)
Key words:
ectopic atrial tachycardia
child
In adults, EAT is known to be caused mainly by diseased
atrial myocardium and local degenerative processes that
do not regress, and patients with EAT respond poorly
to antiarrhythmic drugs [8]. In children, the relatively
immature myocardium and electrophysiologic characteristics of conduction tissue might indicate a different etiology
and treatment response. Few reports of follow-up studies
in children with EAT have shown resolution of the tachycardia after initial drug treatment [1, 2, 7, 8].
1
Department of Pediatrics, National Cheng Kung University Hospital, Tainan; and Department of Pediatrics, Tainan Municipal
Hospital, Tainan.
Received: 24 December 1999.
Revised: 1 March 2000.
Accepted: 11 April 2000.
Reprint requests and correspondence to: Dr. Jing-Ming Wu, Department of Pediatrics, National Cheng Kung University
Hospital, College of Medicine, National Cheng Kung University, 138 Sheng-Li Road, Tainan, Taiwan.
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J Formos Med Assoc 2000 • Vol 99 • No 10
Ectopic Atrial Tachycardia in Children
Because of the paucity of data on the long-term
effectiveness of pharmacologic and non-pharmacologic
therapies, management strategies in patients with this
type of tachycardia are not well defined. The purpose
of this study was to examine the natural history of the
disease, the effectiveness of treatment, and the findings of clinical follow-up in children with EAT.
Materials and Methods
From June 1990 through June 1999, 24 consecutive
patients treated in the National Cheng Kung University
Hospital who were under the age of 15 years at the time
of diagnosis of EAT were included in this study. Detailed
clinical history and physical examination results were
obtained on admission. Chest radiography, echocardiography, 12-lead electrocardiography (ECG), and
24-hour Holter monitor examinations were performed.
EAT was diagnosed if patients met any one of the
following three criteria: wide range of atrial heart rate
during tachycardia with or without abnormal P wave
morphology; tachycardia with ‘warm-up’ and/or ‘cooldown’ phenomenon; or second-degree atrioventricular block without interruption of the atrial rhythm [1].
According to the findings of continuous ECG monitoring during admission or 24-hour ambulatory Holter
monitoring, the tachycardia was further classified as
incessant if it was present for more than 90% of the
time, or as repetitive if it was frequently interrupted by
short sequences of sinus rhythm recurring constantly
during the day [2]. Congestive heart failure was assumed to be present when the cardiothoracic ratio on
the chest radiograph was at least 0.55 and/or the left
ventricular ejection fraction on two-dimensional
echocardiography was 50% or less, combined with
clinical symptoms and signs of heart failure [9].
Patients with hypertrophic cardiomyopathy and patients without obvious congestive heart failure were
initially treated with a beta-blocking agent alone. In
patients with transposition of the great arteries after
Senning operation, both digoxin and procainamide
were used. In other patients, digoxin was used first; a
beta-blocking agent and procainamide were added if
the rate of the EAT was not under control.
Tachycardia was considered to be under control if
the minimum, average, and maximum heart rates were
within the reference range for the patient’s age and no
significant periods of second-degree atrioventricular
block during antiarrhythmic therapy were observed.
The tachycardia was considered to be in spontaneous
remission if no arrhythmia was observed after medication had been discontinued for at least 6 months [7].
J Formos Med Assoc 2000 • Vol 99 • No 10
Results
The study group consisted of 24 children (8 girls and 16
boys) with a median age of 4 months (range, 1 d to 10 yr)
(Table 1). Fetal arrhythmia was recognized in one
patient at the gestational age of 32 weeks but was not
treated during pregnancy. Tachycardia occurred soon
after birth in this patient. Fifteen of the 24 patients had
healthy hearts, six had congenital heart disease (3
developed EAT after cardiac surgery), one had
myocarditis, one had bronchopulmonary dysplasia with
severe pulmonary hypertension, and one had hypertrophic cardiomyopathy. Thirteen of the 24 patients
presented with congestive heart failure, and four patients had prodromal signs of upper respiratory tract
infection. EAT was incessant in 10 and repetitive in 14
patients. Nine of the 10 patients with incessant EAT
were symptomatic, while only four of the 14 patients
with repetitive EAT had symptoms. Symptoms consisted of tachypnea and feeding problems in infants
and toddlers, while school-aged children experienced
fatigue and exercise intolerance.
The ECG characteristics, mode of EAT, and presence of congestive heart failure in the study patients
are summarized in Table 2. The maximal atrial rate of
EAT ranged from 166 to 300 beats per minute, with a
median of 244 beats per minute. Warm-up and/or
cool-down phenomenon was observed during tachycardia in 13 patients, and abnormal P waves were found
in 18 patients. Second-degree atrioventricular block
was found in 13 patients, only four of whom had
congestive heart failure.
The flow diagram of our treatment protocol is
shown in the Figure. Both digoxin (10–20 µg⋅kg–1⋅d–1)
and propranolol (3–6 mg⋅kg–1⋅d–1) were used in the 18
patients with mild to moderate congestive heart failure
at the time of initial treatment. Four of these patients
died within 1 to 2 months: two patients died of uncontrollable EAT that caused the underlying cardiopulmonary function to deteriorate (1 with myocarditis and
1 with bronchopulmonary dysplasia); and two patients
died of unrelated diseases (1 of asplenic syndrome with
complex heart disease and 1 of interrupted aortic arch
with ventricular septal defect). In the remaining 14
patients, digoxin and propranolol treatment was effective
in 13 and ineffective in one. Procainamide (15–40
mg⋅kg –1⋅d–1) was added to this patient’s treatment
protocol to control his EAT.
EAT recurred after discontinuing medication for 1
to 3 months in three patients, who reverted to sinus
rhythm after restarting digoxin and propranolol. However, EAT was only partially controlled in two of these
three patients. In one patient with underlying heart
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J.N. Wang, J.M. Wu, Y.C. Tsai, et al
Table 1. Clinical characteristics of children with ectopic atrial tachycardia
Sex
F
F
M
M
F
M
M
M
M
M
M
F
F
F
M
M
M
M
M
M
M
M
F
F
Age
1
1
1
7
1
1
1
2
2
2
3
4
4
6
7
9
18
21
29
30
6
6
8
10
d
d
d
d
mo
mo
mo
mo
mo
mo
mo
mo
mo
mo
mo
mo
mo
mo
mo
mo
years
years
years
years
CHF
URI
Underlying disease
Drugs
Outcome
–
–
+
–
–
+
+
–
+
–
+
–
–
+
+
+
+
–
+
+
+
+
–
–
–
–
–
–
–
–
–
–
–
–
+
–
–
–
–
–
–
+
+
–
–
–
–
–
–
–
–
–
–
–
HCM
–
VSD, interrupted aortic arch
–
Myocarditis
–
ASD II
Right isomerism
–
–
BPD, severe PAH
–
PA, intact IVS s/p
TGA s/p Senning
TGA s/p Senning
–
–
–
D, I
D, I
D, I
I
D, I
D, I
I
D, I, P
D, I
I
D, I
D, I
D, I
D, I
D, I
D, I
D, I
D, I
D, I
D, P, I
D, P, I
D, I
D, I
I
SR
SR
SR
SR
SR
SR
Continued treatment
SR
Died
SR
Died
SR
SR
Died
SR
SR
Died
SR
SR
SR
SR
SR
SR
Continued treatment
CHF = congestive heart failure; URI = upper respiratory tract infection; D = digoxin; I = propranolol; SR = spontaneous remission;
HCM = hypertrophic cardiomyopathy; P = procainamide; VSD = ventricular septal defect; ASD = atrial septal defect; BPD = bronchopulmonary dysplasia; PAH = pulmonary hypertension; PA = pulmonary atresia; IVS = interventricular septum; s/p = post operative; TGA =
transposition of great arteries.
disease (pulmonary atresia with intact ventricular septum after Brock’s procedure), balloon dilation was
performed because of severe residual pulmonary stenosis. EAT was not observed again in this patient during
2 years of follow-up.
In two patients with severe congestive heart failure,
both of whom had transposition of the great arteries
after Senning operation, digoxin and procainamide
were started. Because EAT could only be partially
controlled, propranolol was added later to the treatment of both patients. Because of marked right atrial
chamber dilation due to severe tricuspid valve regurgitation, both of these patients received mechanical valve
replacement. EAT was not observed again in these two
patients after surgery, during 15 to 19 months’ followup, even after discontinuing drugs.
In four patients without heart failure, we used
propranolol to control EAT. It was fully effective in
three and partially effective in one. Two patients were
symptom-free and propranolol was discontinued 3
months after initiation in these patients. Propranolol
treatment was continued in one patient because of
hypertrophic cardiomyopathy. The remaining patient
received medication during 16 months of follow-up.
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Overall, antiarrhythmic drugs were successful in
controlling EAT in 22 of the 24 patients. During the
follow-up period of 43 ± 31 (mean ± standard deviation)
months (range, 13 mo to 8 yr), 18 of the 24 patients had
spontaneous remission.
Discussion
Even though EAT may present at any age, it is predominantly seen in young infants and children [1, 2]. In this
study, 16 of 24 patients were under 1 year of age at the
time of diagnosis. Seven newborns were noted to have
tachycardia within 1 month after birth, but fetal arrhythmia was found in only one patient. Although no
association between EAT and congenital heart disease
has been previously reported [2], the incidence of
congenital heart disease was 25% in this series.
Donnerstein et al suggested that respiratory syncytial
virus infection can trigger EAT [10]. In our series, only
four patients had prodromal signs of upper respiratory
tract infection, but no virus was identified.
Although the exact pathogenic mechanism of EAT
J Formos Med Assoc 2000 • Vol 99 • No 10
Ectopic Atrial Tachycardia in Children
Table 2. Electrocardiographic characteristics, mode of ectopic atrial tachycardia (EAT), and presence of congestive heart
failure (CHF) in children with EAT
Age
Abnormal P wave Mode of EAT Warm up or cool down 2nd degree AVB Max atrial rate, bpm CHF
1 day
1 day
1 day
7 days
1 month
1 month
1 month
2 months
2 months
2 months
3 months
4 months
4 months
6 months
7 months
9 months
18 months
21 months
29 months
30 months
6 years
6 years
8 years
10 years
+
–
+
–
+
+
+
–
+
+
+
–
+
+
+
+
+
–
+
+
+
+
+
+
Repetitive
Incessant
Incessant
Repetitive
Repetitive
Incessant
Incessant
Repetitive
Incessant
Repetitive
Incessant
Repetitive
Repetitive
Repetitive
Incessant
Incessant
Incessant
Repetitive
Repetitive
Repetitive
Incessant
Repetitive
Repetitive
Repetitive
–
–
+
–
–
+
+
+
–
–
+
–
–
–
+
–
+
+
–
+
+
+
+
+
+
+
–
+
–
–
–
+
+
+
–
+
+
+
–
+
–
+
–
–
–
+
+
–
250
300
197
210
250
200
210
200
214
250
270
200
210
214
250
210
239
210
300
200
210
200
166
220
–
–
+
–
–
+
+
–
+
–
+
–
–
+
+
+
+
–
+
+
+
+
–
–
AVB = atrioventricular block; bpm = beats per minute.
EAT
(n = 24)
ECG, CXR, Holter, Echocardiography
(CHF)
D+P
(n = 2)
(no CHF)
D+I
(n = 18*)
I
(n = 4)
Clinical follow-up 1–3 months
EAT (+)
(n = 2)
EAT (+)
(n = 1)
EAT (-)
(n = 13)
EAT (-)
(n = 3)
EAT(+)
(n = 1)
DC drug
Subsided Recurrence
(n = 10)
(n = 3)
D+I+P
(n = 3)
D+I
(n = 3)
Surgery DC drug
(n = 2) (n = 1)
Surgery
(n = 1)
Subsided Continued drug
(n = 2)
(n = 2)
DC drug
(n = 1)
Continued drug
(n = 1)
Figure. Flow diagram of treatment protocol and patient follow-up. EAT =
ectopic atrial tachycardia; ECG = electrocardiogram; CXR = chest radiograph;
CHF = congestive heart failure; D = digoxin; I = propranolol; DC =
discontinued; P = procainamide. *Four patients died within 1 to 2 months.
J Formos Med Assoc 2000 • Vol 99 • No 10
is uncertain, warm up at tachycardia onset and cool
down during the termination stage strongly suggests
that this is an automatic arrhythmia [1, 2, 9]. In our
study, this phenomenon was observed in 54% of
patients. As noted by Mehta et al, the upper right
atrium appears to be the most common site of origin of
EAT [2]. In this setting, differentiation from sinus
tachycardia can be difficult. Therefore, spontaneous
episodes of second-degree atrioventricular block during tachycardia provide a critical clue for the diagnosis
of EAT [1]. In our study, 54% of patients exhibited this
diagnostic evidence.
The results of this study suggest that the majority of
children with EAT may be treated conservatively using
drugs only. Although digoxin alone may slow down the
heart rate [11], it has not been useful in controlling
EAT [2, 4, 8, 9]. However, digoxin may be beneficial in
temporarily managing coexisting heart failure. Because EAT is most often caused by an abnormal automaticity mechanism, which is a catecholamine-sensitive
tachycardia, beta-receptor blocking agents are usually
tried in children, with varying degrees of success [2,
11–13], especially in young infants [2]. Beta-blocking
agents are usually given in combination with digoxin to
counteract its negative inotropic effect, which might be
769
J.N. Wang, J.M. Wu, Y.C. Tsai, et al
detrimental in patients with EAT and evidence of left
ventricular dysfunction [9]. Class IA antiarrhythmic
agents, particularly quinidine and procainamide, are
known to prolong atrial refractory periods and suppress automaticity; however, neither of these agents
was successful in suppressing EAT in various studies
reported in the literature [2, 11]. In our study, we also
found partial control with the use of procainamide.
The class III antiarrhythmic agent amiodarone has
been reported to be the most effective drug in treating
children with EAT [2, 8, 12]. However, the value of
amiodarone is somewhat limited by the frequency of
undesired side-effects [9].
None of our patients underwent catheter or surgical ablation of the ectopic focus, although surgery was
performed in three patients to correct the underlying
cardiac disease. After the procedure, the dilated cardiac chambers regressed in these patients and EAT was
not observed during the follow-up period of 15 to 24
months. Although chronic tachycardia has sometimes
been associated with signs and symptoms of heart
failure mimicking dilated cardiomyopathy [1, 2, 4], the
pathophysiologic link between chronic incessant tachycardia and ventricular dysfunction is not clear [4].
It is possible that chronic tachycardia and heart failure
may be interrelated, and that control of one may help
control the other.
Spontaneous remission of EAT during long-term
follow-up was not uncommon in our series. Many
researchers also emphasize that EAT can disappear
spontaneously [1, 2, 7, 8]. This may explain why EAT is
only rarely diagnosed in adults. Klersy et al found that
the age at onset of arrhythmia was the single covariate
able to independently predict the possibility of remission [7]. The higher rate of spontaneous remission
among younger patients suggests that immature cardiac tissue or an inflammatory process with subsequent
healing may be responsible for the rhythm disorder in
this age group [7]. In older patients, EAT may be
caused by a local degenerative process that does not
regress, and therefore does not allow spontaneous
remission and displays poor control [7].
On the basis of our findings, we suggest antiarrhythmic drug therapy for children with EAT. Beta-blocking
agents were effective in the control of EAT in children
in this series. For EAT patients who respond poorly to
beta-blocking agents, other drugs such as class I or class
III antiarrhythmic agents or radiofrequency ablation
could be used as alternative treatments. Because our
study was retrospective and not placebo controlled, we
cannot exclude the possibility of spontaneous EAT
770
resolution in some patients whose EAT was believed to
have been controlled with drugs, especially in view of
the high resolution rate.
ACKNOWLEDGMENT: We are grateful to Professor
Ming-Lon Young (University of Miami) for reviewing
this manuscript.
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