Diagnosis, Treatment and Follow-up of Fetal Cardiac Arrhythmia
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Simsek et al.
Diagnosis, Treatment and Follow-up of Fetal Cardiac Arrhythmia
J Pediatr Res 2021
DOI: 10.4274/jpr.galenos.2021.08634
Original Article
Diagnosis, Treatment and Follow-up of Fetal
Cardiac Arrhythmia
Ayse Simsek1, Tülay Demircan2
1Democracy University, Buca Seyfi Demirsoy Training and Research Hospital, Clinic of Pediatrics and Diseases, Division of Pediatric Cardiology,
İzmir, Turkey
2İzmir University of Health Sciences, Tepecik Training And Research Hospital, Clinic of Pediatrics and Diseases, Division of Pediatric Cardiology,
İzmir, Turkey
ABSTRACT
Aim: The importance of managing fetal arrhythmia has increased with the advance of fetal echocardiography. We aimed to describe incidence,
type, clinical characteristics, treatment, and follow-up of fetal arrhythmia diagnosed patients in our center.
Materials and Methods: Fetal echocardiographic examinations performed in our units between January 2016 and September 2019 were
retrospectively evaluated. Fetal arrhythmias and their subtypes were identified using M-mode and Doppler echocardiography in all patients.
Maternal age, gestational age, history of maternal or gestational pathology, diagnoses, and medications were recorded. Fetal arrhythmias
were categorized in three main groups: 1) Irregular heart rhythm (ectopic beats), 2) Bradyarrhythmias: ventricular rate less than 110 bpm; and 3)
Tachyarrhythmias: ventricular rate exceeding 180 bpm.
Results : A total of 60 patients were diagnosed with fetal arrhythmia, corresponding to an overall incidence of 0.5%. Mean maternal and
gestational age of patients with fetal arrhythmia were 28.35 ± 4.88 years and 31.03 ± 5.94 weeks. One patient had maternal systemic disease,
and four had concurrent congenital cardiac disease. Fetal tachycardia, bradycardia, and irregular heart rhythm were detected in 10 (16.6%), 8
(13.3%), and 42 (70%) patients, respectively.
Conclusion: Fetal echocardiography represents the main diagnostic tool for prenatal evaluation of fetal arrhythmias, which have a variable
prognosis depending on the type of arrhythmia. The most common fetal arrhythmia, the irregular heart rhythm, generally does not necessitate
any treatment and resolves spontaneously. The treatment plan in patients should be based on etiology and fetal conditions.
Keywords: fetal echocardiography, fetal arrhythmia, tachycardia, bradycardia, irreguler heart rhytm
Introduction and even fetal mortality (2). Therefore, fetal heart rate
(FHR) should be evaluated carefully in all pregnancies.
Development of fetal echocardiography has led to
Detection of normal fetal cardiac rhythm is based on
an increased awareness among clinicians regarding the
the documentation of regular atrial and ventricular rhythm,
importance of fetal arrhythmia management (1). Although
with a normal rate for gestational age. Each atrial activity is
most fetal arrhythmias are of benign nature, certain types followed by a ventricular activity within the framework of a
of arrhythmias may be associated with certain adverse normal atrio-ventricular (AV) time interval, corresponding
consequences such as fetal hydrops, cardiac dysfunction, to a normal AV conduction rate of 1:1 (3) .
Address for Correspondence
Ayse Simsek, İzmir Democracy University, Buca Seyfi Demirsoy Training and Research Hospital, Clinic of Pediatrics and Diseases, Division of Pediatric Cardiology, İzmir, Turkey
Phone: +90 505 216 59 32 E-mail: draysesimsek@hotmail.com ORCID: orcid.org/0000-0001-6387-4926
Received: 03.03.2021 Accepted: 07.05.2021
©Copyright 2021 by Ege University Faculty of Medicine, Department of Pediatrics and Ege Children’s Foundation
The Journal of Pediatric Research, published by Galenos Publishing House.Simsek et al.
Diagnosis, Treatment and Follow-up of Fetal Cardiac Arrhythmia
Currently, echocardiography represents the most widely analysis was used for demographic, clinical, and medication
used tool for diagnosis and follow-up of fetal arrhythmias variables.
in clinical practice. Although noninvasive techniques to
record electrophysiological signals from the fetal heart have Results
been developed and proved valuable in gathering important Between January 2016 and September 2019, a total of
information on pathophysiology of arrhythmias, they are 12.002 patients underwent fetal echocardiography. Among
mainly used as research tools and in a limited number of these, 60 were diagnosed with fetal arrhythmia. Clinical
centers (4). presentation included irregular rhythm in 42 patients,
Perinatal management of fetal arrhythmia is important bradycardia in 8, tachyarrhythmia in 10, corresponding to
to improve the outcome of affected fetus. Accurate prenatal a fetal arrhythmia incidence of 0.5% in the overall study
diagnosis is crucial to the selection of the appropriate population.
prenatal and postnatal treatments. In this study, we Mean maternal age in patients with fetal arrhythmia
aimed to describe incidence, type, clinical characteristics, was 28.35 ± 4.88 years (min:19, max:38 years), while the
treatment, and follow-up of fetal arrhythmia diagnosed
gestational age was 31.03 ± 5.94 weeks. One patient
patients in our center.
had maternal systemic disease, and 4 had concomitant
congenital cardiac disorders. The demographic and clinical
Materials and Methods
characteristics of patients with fetal arrhythmia were
Fetal echocardiographic examinations performed in our
shown in Table 1.
secondary and tertiary healthcare units between January
2016 and September 2019 were retrospectively evaluated. Ten patients, with an average maternal age of 29.2 ±
Fetal arrhythmias and their subtypes were diagnosed with 3.64 years and gestational age of 31.4 ± 6.36 weeks, had
M-mode and Doppler echocardiography in all patients. fetal tachycardia. All cases with fetal tachycardia had
Maternal age, gestational age, history of maternal or supraventricular tachycardia (SVT). One patient with SVT
gestational pathology, diagnoses, and medications were had cardiac anomaly consisting of single ventricle defect
recorded in patients diagnosed with fetal arrhythmia. The and died in the first postnatal week after birth at 33 weeks
study was approved by the Local Ethical Committee (no: of gestation.
2020/11-66). Bradycardia was present in 8 patients, who had an
Initially, signs of structural cardiac abnormality or cardiac average maternal age of 26.00 ± 4.40 years and gestational
failure were searched in all fetuses. In those diagnosed with age of 27.7 ± 5.47 weeks. Dexamethasone treatment was
fetal arrhythmia, the type of arrhythmia was ascertained started in the patient diagnosed at 29 weeks of gestation
using M-mode echocardiography and Doppler ultrasound. who had maternal antibody positivity. This patient was born
Simultaneous atrial and ventricular wall movements were at 38 weeks of gestation, with a heart rate between 80 and
examined with M-mode echocardiography, while the type 90 bpm. Patient with left atrial isomerism and AVSD was
of arrhythmia was determined using mitral inflow and diagnosed at 23 weeks of gestation. Although salbutamol
aortic outflow (mitral valve flow/aorta flow) technique with was started, this was followed by subsequent termination
Doppler echocardiography. of the pregnancy. Other patient with AV block had a heart
rate between 60 and 70 bpm, and was only followed-up due
Classification of fetal arrhythmias
to the absence of signs of hydrops. Other 4 patients had
Fetal arrhythmias were assessed in three main groups:
sinus bradycardia, with a heart rate greater than 60 bpm,
1) Irregular heart rhythm (ectopic beats); supraventricular
and these patients did not receive any medical treatments
premature beats and ventricular premature beats; 2)
due to absence of the signs of heart failure or hydrops. Also,
Bradyarrhythmias: ventricular rate less than 110 bpm (sinus
no signs of cardiac failure were observed during the follow
bradycardia, 2:1 atrioventricular (AV) block, complete AV
up period.
block, ), and 3) Tachyarrhythmias: ventricular rate exceeding
180 bpm [sinus tachycardia, supraventricular tachycardia Forty-two patients were found to have irregular
(SVT), ventricular tachycardia (VT)]. heart rhythm. The mean maternal and gestational age in
these patients were 28.28 ± 5.23 years and 32.09 ± 5.15
Statistical Analysis weeks, respectively. Among these, only one patient had
We used the Statistical Package for Social Sciences diaphragmatic herniation and supraventriculer premature
(SPSS, version 23.0, SPSS Inc., Chicago, IL, USA) . Descriptive beats coexisting with dextrocardia. In the remainingSimsek et al.
Diagnosis, Treatment and Follow-up of Fetal Cardiac Arrhythmia
Table 2. Echocardiographic results, clinical findings, and outcome of arrhythmia by subtype
Fetal arryhtmia type Incidence Echocardiographic findings Clinical findings Treatment Outcome
Tachycardia 0.08 %
Birth: 36.week recurrent
Case 1 Digoksin episodes of SVT in postnatal
Hydrops fetalis Atrial flutter
(week 25) Sotalol period
Cured with Propranolol
Birth: 34 week SVT
Case 2 Hydrops fetalis Digoksin disappeared in postnatal
Re- entrant SVT
(week 22) Sotalol period
Recurrent episodes of SVT
Case 3 Single ventricle defect Atrial flutter Digoksin
and patients died.
Case (4,5,6,7,8,9,10) Normal Re- entrant SVT Digoksin SVT disappeared
Bradycardia 0.06 %
cAV block
Case 1 Left atrial isomerism - AVSD Salbutamol Patient died in fetal period
bradycardia
cAV block
Case 2 Normal Normal
bradycardia
Maternal Anti-Ro + cAV block
Case 3 Dexamethasone Cured with dexamethasone
Normal bradycardia
Bradycardia disappeared in
Case 4 Aortic arch hypoplasia Bradycardia -
postnatal period
Case (5,6,7,8) Normal Sinus bradycardia - Postnatal normal
Irregular Heart Rhythm 0.34 %
Dextrocardia, diafragmatic Patient died in postnatal
Case 1 Ectopic beats -
hernia period
Case 2-42 Normal Ectopic beats - Normal
SVT: supraventricular tachycardia, cAV block: complete atrioventricular block
cases, no cardiac pathology was found. The patient with
Table 1. Demographic and clinical characteristics in patients
with fetal arrhythmia diaphragmatic herniation died at postnatal 24 hours.The
n = 60 irregular heart rhythm was normalized in the remaining
group.
Gestational age (weeks)
31.03±5.94
(mean±SD) Thus, majority of our patients diagnosed with fetal
Maternal ages (years)
28.35±4.88
arrhythmia had irregular cardiac rhythm (70%), followed
(mean±SD)
by SVT (16.6%), and bradycardia (13.3%). Echocardiographic
Congenital heart disease n(%) 4 (6.6%) results, clinical findings, and outcome of arrhythmia were
Maternal disease n (%) 1 (1.6%) shown in Table 2.
Mortality n(%) 3 (5%)
Fetal tachycardia n (%) 10 (16 %)
Discussion
Maternal ages (years) 29.2 ± 3.64 Fetal arrhythmias occur in a small percentage (0.6-
Gestational age (weeks) 31.4 ± 6.36
2.0%) of all pregnancies (5, 6) , and frequency of pediatric
Fetal bradycardia n (%) 8 (13.3%)
cardiologic referral of these patients was reported between
Maternal ages (years) 26.00 ± 4.40
Gestational age (weeks) 27.7 ± 5.47 10% and 20% (7). Although the incidence rates have not
Irregular cardiac rhythm n (%) 42 (70%) been provided in some previous studies due to admission
Maternal ages (years) 28.28 ± 5.23 of patients specifically diagnosed with fetal arrhythmia to
Gestational age (weeks) 32.09 ± 5.15
tertiary referral centers (8). We chose to present such dataSimsek et al.
Diagnosis, Treatment and Follow-up of Fetal Cardiac Arrhythmia
since patients from a secondary healthcare facility were also fetus sotalol, flecainide, and digoxin are commonly used,
included in the sample population, in addition to a tertiary while flecainide and sotalol have been shown to be readily
center. Thus, based on our results the incidence of fetal transferred through the placenta and therefore may be
arrhythmia was in the order of 0.5%. used for hydropic fetuses (14). In a study by Jaeggi et al.
flecainide has been found to be slightly more effective
Fetal tachycardia
than sotalol in hydropic fetuses (15). When no response is
Tachycardia is generally defined as the presence of obtained with single-agent therapy, combinations may be
sustained fetal heart rate exceeding 180 bpm. The detection tried amiodarone/digoxin, amiodarone/flecainide, sotalol/
of a fast heart rate greater than 180 bpm in a fetus digoxin, and sotalol/flecainide on the basis of studies
constitutes a medical emergency, since it may lead to fetal reporting benefit (15, 16) Arrhythmia could be terminated
hydrops, premature delivery as well as increased perinatal with digoxin in all of our patients with re-entrant SVT.
morbidity and mortality. Sustained tachycardia with high
Currently, digoxin and sotalol are used to treat AF, with
ventricular rate at earlier gestational weeks is more likely
sotalol preferred in the presence of hydrops. Of our two
to be associated hydrops fetalis. In the current study, two
cases with AF, one responded to digoxin, while the other
patients had signs of hydrops fetalis due to SVT occurring at
was followed-up with digoxin/sotalol combination therapy.
25 and 22 weeks of gestation.
However, this latter patient died at postnatal week 1 due to
Causes of fetal tachycardia include sinus tachycardia, coexisting cardiac anomaly.
re-entrant supraventricular tachycardia, atrial flutter,
atrial ectopic tachycardia, junctional ectopic tachycardia, Fetal bradyarrhyt,hmia
and ventricular tachycardia. Among these, re-entrant Fetal bradycardia is defined as a regular heart rate
supraventricular tachycardia represents the most common below 100–110 bpm without taking the gestational age
type of fetal tachycardia (9) ,comprising almost two-thirds of the fetus into consideration (6). It may be caused by
of all cases with this condition (5). Re-entrant tachycardia sinus bradycardia, premature atrial contractions (PAC) with
mostly occurs between 24 and 32 weeks of gestation. block, or AV block. Transient bradycardia generally occurring
Eight of our patients with a mean gestational age of during the second trimester is benign and does not require
31.4 ± 6.36 weeks had re-entrant tachycardia. The second treatment (14).
most common type of tachycardia was AF, which was Persistent fetal bradycardia is relatively rare. Slow heart
detected in two cases. On the other hand, junctional ectopic rate may develop due to a congenital or acquired injury in the
tachycardia and ventricular tachycardia are uncommon and sino-atrial node. Possible causes include viral myocarditis,
were not identified in any of our patients. inflammation and fibrosis due to collagen tissue disorders,
Approximately 2% of the patients with fetal tachycardia maternal treatment with β blockers and sedatives, fetal
have been reported to have coexisting congenital cardiac distress, hypoxia and acidosis. Additionally, in patients with
disorders (10, 11). In another study, 15% to 18% of persistent sinus bradycardia, long-QT syndrome should
the fetuses with fetal arrhythmia were found to have be investigated during the postnatal period. According
concomitant congenital cardiac abnormalities (12). In our to Mitchell et al., 40% of the long QT syndrome cases
study, congenital cardiac disorder was present in 12.5% evaluated by fetal magnetocardiography (fMCG) were
of the patients with SVT and in 6.6% of those with fetal referred due to sinus bradycardia (17) .
arrhythmia. Nearly 50% of the cases with complete AV block
In one study involving 29 cases diagnosed with have been associated with complex cardiac malformations
fetal arrhythmia, subtypes were fetal tachycardia, fetal (18) (left atrial isomerism, atrioventricular septal defect,
bradycardia, and irregular heart rhythm in 41.4% , 17.2%, corrected transposition of the great arteries) or maternal
and 41.4 % of the cases respectively (13). In the current autoantibodies (associated with autoimmune diseases such
study 16.6% of the patients with fetal arrhythmia had fetal as systemic lupus erythematosus) (19).
tachycardia, and the most common type was irregular heart Of the three patients with complete AV block in our
rhythm. study, two had coexisting anomalies, one had left atrial
Currently, there is no regarding the first agent of choice isomerism and AVSD, and one had maternal anti-Ro
for the treatment of re-entrant SVT, and the decision should antibody positivity. In this regard, it should be remembered
be based on the condition of the fetus. For a non-hydropic that the combination of complete AV block and majorSimsek et al.
Diagnosis, Treatment and Follow-up of Fetal Cardiac Arrhythmia
structural heart disease carries high mortality. When coexisting cardiac anomaly. In another report describing
hydrops is present, the mortality approaches 100% (5). In 306 fetuses with an irregular rhythm, isolated extrasystoles
this study, the pregnancy associated with fetal left atrial were diagnosed in 298 and were still present in 10 (3.4%) at
isomerism was terminated. delivery (26). Among our patient group, 1 (2.3%) had extra-
Treatment of fetal bradycardia depends on the etiology, systoles that persisted for up to 3 days following delivery. In
ventricular rate, and presence or absence of cardiac failure. If patients with fetal ectopic beats, the risk of developing fetal
the fetal heart rate is less than 55 to 60 bpm, beta-mimetics tachycardia is estimated to be 0.5% to 1%. The presence of
(terbutaline, salbutamol, isoprenaline) may be tried as a couplets and blocked atrial bigeminy increases this risk to
first line therapy (14, 20). These agents may increase the approximately 10% . Fetal ectopic beats are generally of
fetal ventricular rate by around 10-20% and reverse hydrops benign nature, most resolving spontaneously. No medical
as well (21). Immune-mediated AV block may benefit from treatment is considered necessary for this patients (14)
in utero treatment with fluorinated steroids, intravenous although it is recommended that these patients should be
immunoglobulin, or both. Dexamethasone is believed to assessed on a weekly basis with respect to SVT and VT.
reduce inflammation (22) . Although no consensus exists,
Study Limitations
many clinicians administer dexamethasone 4 to 8 mg/d
to treat second degree AV block, recent onset AV block, Absence of long time follow up findings in postnatal
or severe cardiac dysfunction and hydrops. In our study, period could be assessed as a limitation of our study.
salbutamol treatment was given during the fetal period in
our patient with atrial isomerism-AVSD, while the other Conclusions
patient with maternal antibody positivity benefited from Fetal echocardiography represents the main diagnostic
dexamethasone. tool for prenatal evaluation of fetal arrhythmias. In all patients
with suspected tachyarrhythmia or bradyarrhythmia, a
Irregular cardiac rhythm
fetal echocardiography should be performed to evaluate
Irregular heart rhythm, also called a premature beat, cardiac structures and functions. Fetal arrhythmias may
premature contraction, ectopic beat or extra-systole can present with variable types and prognostic consequences,
originate from the atria, the atrioventricular junction, or with no direct effects on fetal growth and development.
the ventricle, and bypasses the sinus node. Irregular heart Etiology and fetal condition are the main determinants of
rhythms are the most common abnormal rhythms seen in the management strategy for fetal tachyarrhythmias and
clinical practice. bradyarrhythmias.
Fetal ectopy occurs in up to 1 to 2% of all pregnancies
and has been reported to be a relatively benign condition Acknowledgment: None
(5). In a study by Capuruço et al. fetal ectopic beats were the
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