Journal of Pediatric Cardiology and Cardiac Surgery 8(2): 92‒95 (2024)

Case Report

Successful Pacemaker Implantation for Congenital Complete
Heart Block With Pulmonary Valve Stenosis
in an Extremely Low Birth Weight Infant
Akio Kato, MD1), Masataka Kitano, MD1), Atsuya Shimabukuro, MD1),
Seiichi Sato, MD, PhD1), and Masahiko Nishioka, MD2)
1) Department of Pediatric Cardiology, Okinawa Prefectural Nanbu Medical Center & Childrenʼs Medical Center,Okinawa, Japan

2) Department of Pediatric Cardial Surgery, Okinawa Prefectural Nanbu Medical Center & Childrenʼs Medical Center,Okinawa, JapanCongenital complete heart block (CCHB) occurs because of transplacental antibodies such as anti-SS-A andanti-SS-B. CCHB is a potentially fatal condition, in particular in very/extremely low birth weight infants. Coexisting structural heart disease is another significant risk factor for CCHB. The survival rates after pacemaker
implantation, either temporary or permanent, remain low. To the best of our knowledge, no criteria have been
established for the minimum weight and earliest gestational age for treatment thus far. Herein, we present a caseof an extremely low birth weight infant (ELBWI) with CCHB caused by positive anti-SS-A/Ro antibodies of themother and significant pulmonary valve stenosis. The infant underwent temporary pacing implantation on theday of birth with a weight of 850 g. Percutaneous balloon pulmonary valvuloplasty was performed at the age of106 days when body weight 2.6 kg. This consecutive approach provided a favorable outcome. We propose that
epicardial temporary pacing could avoid postnatal heart failure in ELBWI with CCHB even when structuralheart disease was present.

Keywords: congenital complete heart block, extremely low birth weight infant, structural heart disease,pulmonary valve stenosis, catheter intervention

Introduction

Case Report

Congenital complete heart block (CCHB) occurs
because of transplacental antibodies such as anti-SS-A
and anti-SS-B antibodies, which are present in the motherʼs body. CCHB incidence ranges from 1 in 15,000 to 1 in
20,000 births.1, 2) Structural heart disease and low birthweight are recognized risk factors of CCHB.3) Herein, wereport a case of an extremely low birth weight infant(ELBWI) with CCHB and severe pulmonary valve stenosis(PVS) who underwent pacemaker implantation and percutaneous balloon pulmonary valvuloplasty (BPV).

A 35-year-old pregnant woman with elevated levels ofanti-SS-A/Ro antibodies (>1200 U/mL; normal value,<10 U/mL) was referred to our hospital at 14 weeks ofgestation. At 16 weeks of gestation, the fetus was diagnosed as second-degree atrioventricular heart block,with atrial and ventricular rates of 130 and 65 beats/
minute, respectively. Since concurrent myocarditis wasdetected in the fetus, enteral dexamethasone therapy(4 mg daily) was initiated to prevent progression of fetal
myocarditis. Unfortunately, atrioventricular conduction
deteriorated into complete heart block at 19 weeks ofReceived: October 16, 2023; Accepted: December 30, 2023
J-STAGE Advance Published Online: July 9, 2024
Corresponding author: Akio Kato, MD, Department of Pediatric Cardiology, Okinawa Prefectural Nanbu Medical Center & Childrenʼs
Medical Center, 118‒1 Arakawa Haebaru, Okinawa 901‒1105, Japan
E-mail: akki.kato@gmail.com
Akio Kato ( https://orcid.org/0000-0002-8727-5634)
doi: 10.24509/jpccs.23-017© 2024 Japanese Society of Pediatric Cardiology and Cardiac Surgery
This is an open access article under the CC BY-NC-ND license (https://creativecommons.org/licenses/by-nc-nd/4.0/)

93

gestation. Eventually, the mother was hospitalized for
meticulous monitoring and ritodrine was commenced
at 26 weeksʼ gestation. At that time, the fetus had a cardiovascular profile score (CVPS) of 6; due to pericardial
effusion, a cardiothoracic area ratio (CTAR) 45%, andpulsatile umbilical venous blood flow. We detected
hyperintensity of the pulmonary valve, but no acceleration of blood flow across it. The fetal heart rate slightly
increased from 51 to 56 beats/minute.
At 27 weeks of gestation, ritodrine had to be discontinued because of maternal liver dysfunction. Fetal ascites appeared at 27 weeks +2 weeks. At 27+ 3 weeks, fetal
ascites increased although CVPS was 5 and biophysicalprofile score was 8, CTAR got worse to 55%, fetal movement decreased, and the heart rate dropped to 48 beats/
minute; these changes necessitating an urgent cesarean
section. The infant born was a female weighing 850 g.
Apgar scores were 4 and 5 at 1 and 5 minutes, respectively. Her heart rate was 48 beats/minute. Immediately
after birth, the infant was intubated and transferred tothe operating room. Pulmonary surfactant was administrated into the trachea and umbilical arterial and venous
catheters were placed.
Subsequently, a temporary pacing lead was implanted
as follows. Through a median sternotomy, an Osypka
heart wire (TME 56-T) bipolar (Osypka, Tokyo, Japan)
measuring 60 cm in length was affixed to the anterior
epicardium of the right ventricle using 7-0 monofilament sutures. Then, pacing was started at 80 beats/
minute. Postoperative echocardiography illustrated thatthe diastolic left ventricular intradiameter was 10.2 mm
and fractional shortening was 30%. It also showedmyocardial hypertrophy, for which hydrocortisone(3 mg/kg/day) was initiated in order to prevent further
myocardial damage and late circulatory dysfunction in
the infant. This treatment was tapered off over a periodof 3 weeks. PVS was another lesion detected. The pacemaker lead was replaced at 38, 73, and 124 days of age
because pacing capture threshold was elevated beyond
an acceptable level.
Regarding PVS, the annular diameter of the pulmonary valve was 4.4 mm (Z-score −1.6) at birth, andblood flow velocity was 3.2 m/s across the orifice. The
velocity increased up to 4.5 m/s after the third placement of the pacemaker lead. Right ventricular pressure
was estimated higher than left ventricular pressure. The
foramen ovale shunted right-to-left, leading to persistenthypoxemia. Percutaneous BPV was performed at 106
days of age (2.6 kg body weight) since oxygen saturation
fell below 80% during crying.
Finally, at 4 months of age (weight, 3.6 kg), an intraperitoneal generator (ZYPHYR SR 5620, Abbott Medical Japan LLC., Tokyo, Japan) and an epicardial ventricular lead (CapSure Epi model 4965, Medtronic INC.,
Minneapolis, Minnesota, USA) were implanted onto theinferior surface of the right ventricle.
The infant was discharged 19 days after implanting thepermanent pacemaker. At 15 months of age, a generator
replacement was carried out because the skin becamerather thin around the generator pocket.

Discussion
Treatments for CCHB have improved. Still, high-riskcases do not diminish markedly. Recent reports haveidentified several risk factors leading to prenatal or
postnatal death in infants with neonatal cardiac lupus
and in fetuses with second- or third-degree atrioventricular block. These include the maternal/intrauterine
diagnosis of myocarditis, endocardial fibroelastosis,
systemic lupus erythematosus, Sjögrenʼs syndrome, AV
block diagnosis before 20 weeks, ventricular rate of <50beats/minute, fetal hydrops, comorbid congenital heart

Table 1 Prior reports of pacemaker therapy at birth for congenital complete heart block in patients born with 28
weeks of gestation or lessYear20077)
20006)
20128)
Our case

Gestational week(weeks)

Birth weight(g)Heart rate atbirth (/min)

2726
28
28
27

980
830
650
840
850

5550
̶
̶

48

Age at operation
Structural heart
for initial pacing Pacemaker typedisease(days)
20
1
10

Epicardial
Transthoracic
permanent

None
None
None

Epicardial

PVS

Outcomealive
deaddead
alive
alive

PVS: pulmonary valve stenosis© 2024 Japanese Society of Pediatric Cardiology and Cardiac Surgery

94

disease, and presence of left ventricular dysfunction atdiagnosis.3‒5) Our patient exhibited quite high risks for
CCHB, which was diagnosed at 19 weeks of gestationalage, extremely early term and low birth weight of 850 g,and significant pulmonary valve stenosis. After extensive
discussions among the medical staff as well as with thepatientʼs family, an approach for aggressive treatment
was selected, and the approach turned out to provide afavorable outcome.
CCHB treatment is particularly challenging in ELBWIs; only a few cases having been reported in literature.
In previous reports, pacemaker implantation was performed in four ELBWIs before 28 weeks of gestationalage (Table 1).6‒8) Among the four cases, only two survived, with the earliest gestational age and minimum
weight being 27 weeks and 840 g, respectively. To thebest of our knowledge, this case report represents thesuccessful implementation of pacemaker implantation
at the lowest weight of 27 weeks gestation.
The approach how to implant a pacemaker for CCHB
remains undetermined in ELBWI. Nürnberg et al
employed transthoracic pacing in a 26-week-old infant
weighing 830 g,6) whereas Shepard et al performed
permanent pacemaker implantation in infants weighing 630 g and 840 g.8) There was only one case report
describing use of temporary pacing in ELBWI.7) For premature infants, we considered that temporary pacing via
an epicardial approach was reasonable, given their small
thorax and abdomen as well as their immature skin.
The prognosis is extremely poor in low birth weight
infants with CCHB and coexisting structural heartdisease.5, 9) Previous reports indicated that structural
heart disease occurred in 53% of CCHB cases, with amortality rate exceeding 45%.5) The survival rate wasextremely low in those with heterotaxy.5, 9) In the presentpatient, PVS was considered moderate or severer. The
obstruction got worse postnatally causing hypoxia. Percutaneous BPV, which is less invasive than surgery, wassafely achieved. We attributed the favorable outcome tothe fact that surgery was not mandatory for the degreeof PVS; the lesion was responsible for hypoxic circumstance but did not pose a loss of cardiac output.

Conclusion
The present case demonstrates that preterm ELBWIs
with CCHB and coexisting severe PVS were successfully
treated with combination of pacemaker implantation
J Pediatr Cardiol Card Surg Vol. 8, No. 2 (2024)

and percutaneous BPV. Gestational age of over 27 weeks
and birth weight exceeding 800 g may be a potential
indicator for survival with appropriate therapy. This
report, although represents a single patient, implies thatthese cutoff figures would be reasonable and that theprognosis would also depend on how severe the coexisting structural heart diseases were.
Funding
The authors have no funding sources relevant to thisarticle to disclose.
Financial Disclosure
The authors have no financial interests relevant to thisarticle to disclose.
Conﬂicts of Interest
The authors have no conflicts of interest to disclose.
Author Contribution
KA drafted the original manuscript. KM and SA had
revised this manuscript, and SS and NM had finallyreviewed the manuscript and approved the published version.

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