![Page 1: Successful Implantation of an Intracardiac Defibrillator in an Infant With Long QT Syndrome and Isolated Noncompaction of the Ventricular Myocardium](https://reader031.vdocuments.us/reader031/viewer/2022020614/575094451a28abbf6bb78bc2/html5/thumbnails/1.jpg)
CASE REPORT
Successful Implantation of an Intracardiac Defibrillatorin an Infant With Long QT Syndrome and IsolatedNoncompaction of the Ventricular Myocardium
Ozge Surmeli Onay • Isil Yildirim •
Burcin Beken • Sevcan Erdem • Tevfik Karagoz •
Mustafa Yilmaz • Sule Yigit
Received: 3 November 2011 / Accepted: 27 February 2012 / Published online: 23 March 2012
� Springer Science+Business Media, LLC 2012
Abstract Congenital long QT syndrome (LQTS) is an
inherited disorder characterized by QT prolongation and
polymorphic ventricular tachycardia known as torsade de
pointes. The underlying cellular mechanism is prolonged
ventricular repolarization caused by mutations in genes
encoding cardiac ion channels or membrane adaptors. The
disease can be diagnosed at any age and, very rarely, it can
be diagnosed prenatally or in the neonatal period. Isolated
noncompaction of the ventricular myocardium (INCVM) is
defined as the presence of prominent ventricular trabecu-
lations and deep intertrabecular recesses within the endo-
myocardium. This report describes a newborn baby
presenting with polymorphic ventricular tachycardia whose
diagnosis was LQTS and INCVM. Ventricular tachycardia
did not respond to medical treatment, and a transient
epicardial pacemaker was inserted surgically on his 30th
day of life for atrioventricular block and bradycardia. The
transient epicardial pacemaker was upgraded to an epi-
cardial intracardiac defibrillator on his 40th day. The
concomitant occurrence of INCVM, LQTS, and atrioven-
tricular block needs to be evaluated further.
Keywords Atrioventricular block � ICD implantation �Infant � Isolated noncompaction of the ventricular
myocardium � Long QT syndrome
Congenital long QT syndrome (LQTS) is an inherited
disorder characterized by QT prolongation in the electro-
cardiogram (ECG) and polymorphic ventricular tachycar-
dia, known as torsade de pointes (TdP), which may cause
syncope and sudden cardiac death [8]. Isolated noncom-
paction of the ventricular myocardium (INCVM) is defined
as the presence of prominent ventricular trabeculations and
deep intertrabecular recesses within the endomyocardium
[23]. Several electrocardiographic alterations such as ST
depression and flat or negative T-waves, bundle branch
block and Wolff–Parkinson–White (WPW) syndrome
related to INCVM have been reported [15]. We report a
case of a newborn boy with a diagnosis of INCVM, LQTS,
and progressive complete atrioventricular block (AVB)
who had an intracardiac defibrillator (ICD) implanted with
a subcutaneous array system.
Case Report
A 19 day-old, 3,200 g full-term male baby with a diagnosis
of LQTS and polymorphic ventricular tachycardia was
referred to our hospital for ICD implantation. The boy’s
O. S. Onay (&) � S. Yigit
Division of Neonatology, Department of Pediatrics,
Hacettepe University, Faculty of Medicine,
Adnan Saygun Caddesi, Ankara, Turkey
e-mail: [email protected]
I. Yildirim � T. Karagoz
Division of Pediatric Cardiology, Department of Pediatrics,
Hacettepe University, Faculty of Medicine,
Adnan Saygun Caddesi, Ankara, Turkey
B. Beken
Department of Pediatrics, Hacettepe University, Faculty
of Medicine, Adnan Saygun Caddesi, Ankara, Turkey
S. Erdem
Pediatric Cardiology Unit, Cukurova University,
Faculty of Medicine, Adana, Turkey
M. Yilmaz
Department of Cardiovascular Surgery, Hacettepe University,
Faculty of Medicine, Adnan Saygun Caddesi, Ankara, Turkey
123
Pediatr Cardiol (2013) 34:189–193
DOI 10.1007/s00246-012-0279-7
![Page 2: Successful Implantation of an Intracardiac Defibrillator in an Infant With Long QT Syndrome and Isolated Noncompaction of the Ventricular Myocardium](https://reader031.vdocuments.us/reader031/viewer/2022020614/575094451a28abbf6bb78bc2/html5/thumbnails/2.jpg)
family history was remarkable for consanguinity of the
parents and early neonatal deaths of the previous three
siblings due to malignant cardiac arrhythmias. Fetal
tachycardia was diagnosed at 6 months of pregnancy, and
beta-blocker was administered to the mother. However it
was discontinued because no response could be achieved.
After delivery, the boy was hospitalized in the neonatal
intensive care unit for 16 days with the diagnoses of con-
genital LQTS and ventricular tachycardia. Propranolol and
lidocain infusions were started, but the ventricular tachy-
cardia could not be controlled, so he was referred to our
hospital for ICD implantation.
At admission, the boy’s physical examination was nor-
mal except for arrhythmia. Echocardiographic evaluation
showed noncompaction involving the left ventricle with an
ejection fraction of 67 % and a patent foramen ovale
(Fig. 1). The patient had a brain natriuretic peptide level of
855.18 pg/ml (range, 0–100 pg/ml), a total calcium level of
10.36 mg/dl (range, 9–11 mg/dl), and a magnesium level
of 1.91 mg (range, 1.4–1.9 mg).
Cardiac and Holter monitoring showed first-degree and
intermittent second- and third-degree AVB with T-wave
alternans, biphasic T-waves, and a corrected QT (QTc)
interval of 630 ms. Holter monitoring further showed TdP
and nonsustained polymorphic ventricular tachycardia
attacks at intervals shorter than 10 s and at a rate of 150 to
200 beats/min (Fig. 2). Diffuse prolongation of both de-
and repolarization intervals also was noted with Holter
monitoring.
Lidocain infusion (30 lg/kg/min), MgSO4 infusion
(0.3 mg/kg/h), and oral beta-blocker (propranolol) (2 mg/
kg/day) were administered. Urine and blood amino acid
paper chromotography, performed to exclude underlying
metabolic diseases, was normal. A transesophageal elec-
trophysiologic study showed a 2:1 AVB, intermittent
complete AVB, nonsustained ventricular tachycardia, a
long QT interval, and electrocardiographic findings con-
sistent with diffuse ventricular transmission defect (Fig. 3).
Although medical treatment decreased the frequency of
the ventricular tachycardia attacks, the patient continued to
have ventricular tachycardia during bradycardia. A tran-
sient epicardial pacemaker was inserted surgically on his
30th day of life for AVB and bradycardia, which was
upgraded to an epicardial ICD on his 40th day.
With the boy under general anesthesia, a short right
lateral paraumblical incision was made for the ICD
implantation. Using the previous subxhyphoid incision
from the pacemaker, both electrodes of the 35 cm bipolar,
steroid-eluting, pace-sensing lead (Bipolar CapsureEpi IS-
1, Model 4968; Medtronic, Minneapolis, MN, USA) were
sutured to the epicardium of the anterior right ventricular
wall. A subcutaneous defibrillation electrode (35 cm, uni-
polar endocardial superior vena cava lead for cardioversion
and defibrillation; Unipolar Transvene-SVC Model 6937,
Medtronic) was passed through the right rectus muscle and
tunneled subcutaneously to a position below the left
scapula. Subsequently, the ICD device (Maximo II VR
D284VRC; Medtronic) was inserted into an abdominal
pocket behind the right rectus abdominis muscle (Fig. 4).
The boy’s postoperative course was uneventful, and he
was discharged 3 days after the operation with propranolol.
During the 6 month follow-up period, the boy had two
attacks of ventricular tachycardia, which were controlled
with antitachycardia pacing, and no attacks of ventricular
fibrillation were determined (Fig. 5).
Discussion
Noncompaction of the left ventricle is classified as a pri-
mary genetic cardiomyopathy [6, 7, 11]. The major clinical
manifestations of INCVM are heart failure, atrial and
ventricular arrhythmias, and thromboembolic events
including stroke [4, 16]. Sinus bradycardia and progressive
AVB in patients with INCVM [3, 17] and LQTS also have
been described [8, 13]. Only one report describes a patient
presenting with INCVM, LQTS, and congenital AVB [6].
The reported patient showed intermittent AVB and
additional electrocardiographic findings in concordanceFig. 1 Left ventricular noncompaction observed with two-dimen-
sional echocardiography
190 Pediatr Cardiol (2013) 34:189–193
123
![Page 3: Successful Implantation of an Intracardiac Defibrillator in an Infant With Long QT Syndrome and Isolated Noncompaction of the Ventricular Myocardium](https://reader031.vdocuments.us/reader031/viewer/2022020614/575094451a28abbf6bb78bc2/html5/thumbnails/3.jpg)
with diffuse ventricular conduction delay, which is dif-
ferent from the case described by Drago et al. [6]. The
third-degree AVB in our patient may have developed
secondary to LQTS or secondary to antiarrhythmics on
the basis of LQTS and INCVM despite appropriate
dosages.
Fig. 2 Holter monitoring showing recurrent torsade de pointes (Tdp) and polymorphic ventricular tachycardia attacks
Fig. 3 Simultaneous esophageal and surface electrocardiographic (ECG) recordings demonstrating atrioventricular (AV) dissociation, QT
prolongation, and biphasic T-waves. Eso, esophageal recording; P p-wave; R R-wave; A atrium recording; V ventricle recording
Pediatr Cardiol (2013) 34:189–193 191
123
![Page 4: Successful Implantation of an Intracardiac Defibrillator in an Infant With Long QT Syndrome and Isolated Noncompaction of the Ventricular Myocardium](https://reader031.vdocuments.us/reader031/viewer/2022020614/575094451a28abbf6bb78bc2/html5/thumbnails/4.jpg)
Congenital LQTS is a genetic channelopathy with var-
iable penetrance characterized by abnormally prolonged
ventricular repolarization with an increased propensity to
syncope and polymorphous ventricular tachycardia, which
may lead to ventricular fibrillation and sudden cardiac
death. More than 350 mutations in 12 LQTS-susceptible
genes have been identified, with the majority of the patients
having mutations in one of three genes: KCNQ1 (LQTS1),
KCNH2 (LQTS2), and SCN5A (LQTS3) [8, 20].
Ogawa et al. [14] reported two patients with LQTS and
INVCM whose genetic workup showed two different
mutations in KCNH2. Drago et al. [6] could not identify
any known mutations in their patient, who presented with
LQTS, INCVM, and congenital AVB. Studies have found
SCN5A associated with LQTS, progressive cardiac con-
duction defects, isolated cardiac conduction disease, AV
conduction block, and Brugada syndrome [12, 20, 22].
Recently, mutations in SCN5A also have been identified in
patients with INCVM [24]. Unfortunately, genetic study is
not available at our center, so we can only speculate that
the mutation in our patient may have been in the gene
SCN5A.
Management of patients with ventricular tachycardia
focuses on controlling the tachycardia. The reported patient
presented with prolongation of the QT interval, intermittent
AVB, frequent attacks of polymorphic ventricular tachy-
cardia, and diffuse ventricular conduction delay. Lidocaine
and magnesium infusions and oral beta blocker therapy
were started for rhythm control. The literature contains
limited reports on the use of magnesium for children with
ventricular tachycardia and LQTS [9, 10]. It is thought that
magnesium abolishes triggered activity by inhibiting early
and late depolarizations directly rather than by shortening
action potential duration [10]. Pacing therapy for LQTS
with AVB and pause-dependent TdP has been used pre-
viously. However, it is known that arrhythmic death still
may occur for well-controlled, high-risk patients despite
combined therapy with beta-blocker and pacemakers [5].
For the reported patient, although a transient pacemaker
controlled the ventricular tachycardia attacks, implantation
of an ICD was performed due to the history of three pre-
vious sibling deaths.
Implantation of ICDs in pediatric patients poses several
difficulties. Despite the advancements in technology that
caused the downsizing of pulse generators as well as
improvements in lead design and shock waveforms, pedi-
atric patients present challenges in terms of patient size and
growth and the common coexistence of congenital heart
diseases [1, 2]. Relative to the venous diameter and tho-
racic anatomy of the infants, transvenous leads are large in
caliber and length. Epicardial patches require sternotomy
Fig. 5 Intracardiac electrocardiogram (ECG) showing ventricular tachycardia and antitachycardia pacing showing termination of ventricular
tachycardia (VT)
Fig. 4 Chest X-ray, anteroposterior view. The subcutaneous (SQ)
defibrillation electrode is positioned posterior to the left chest wall
beneath the scapula, with the epicardial pacing leads placed on the
right ventricle and the active generator in the upper right abdomen
192 Pediatr Cardiol (2013) 34:189–193
123
![Page 5: Successful Implantation of an Intracardiac Defibrillator in an Infant With Long QT Syndrome and Isolated Noncompaction of the Ventricular Myocardium](https://reader031.vdocuments.us/reader031/viewer/2022020614/575094451a28abbf6bb78bc2/html5/thumbnails/5.jpg)
or thoracotomy, with higher rates of insulation and con-
ductor fractures as well as the risk for the development of
restrictive pericardial lesions due to the large surface area
of the patches. Implantation techniques using a subcuta-
neous array and an abdominally placed ICD generator have
been described previously [1, 2, 18, 19, 21]. However,
experience with infants younger than 6 months is limited.
The concomitant occurrence of INCVM, LQTS, and
AVB needs to be evaluated further. Meanwhile, echocar-
diographic screening of all patients with LQTS, AVB, or
both, and ECG screening of patients with a diagnosis of
INCVM is of utmost importance and should be adopted as
a clinical policy.
References
1. Bauersfeld U, Tomaske M, Dodge-Khatami A, Rahn M, Kel-
lenberger CJ, Pretre R (2007) Initial experience with implantable
cardioverter defibrillator systems using epicardial and pleural
electrodes in pediatric patients. Ann Thorac Surg 84:303–305
2. Berul CI, Triedman JK, Forbess J (2001) Minimally invasive
cardioverter defibrillator implantation for children: an animal
model and pediatric case report. Pacing Clin Electrophysiol 24:
1789–1794
3. Celiker A, Ozkutlu S, Dilber E, Karagoz T (2005) Rhythm
abnormalities in children with isolated ventricular noncompac-
tion. Pacing Clin Electrophysiol 28:1198–1202
4. Chin TK, Perloff JK, Williams RG, Jue K, Mohrmann R (1990)
Isolated noncompaction of left ventricular myocardium: a study
of eight cases. Circulation 82:507–513
5. Dorostkar PC, Eldar M, Belhassen B, Scheinman MM (1999)
Long-term follow-up of patients with long-QT syndrome treated
with beta-blockers and continuous pacing. Circulation 100:
2431–2436
6. Drago F, Stefano Silvetti M, Annichiarico M et al (2010)
Biventricular pacing in an infant with noncompaction of the
ventricular myocardium, congenital AV block, and prolonged QT
interval. J Interv Card Electrophysiol 28:67–70
7. Elshershari H, Okutan V, Celiker A (2001) Isolated noncom-
paction of ventricular myocardium. Cardiol Young 11:472–475
8. Garson A Jr, Dick M, Fournier A et al (1993) The long QT
syndrome in children: an international study of 287 patients.
Circulation 87:1866–1872
9. Hoshino K, Ogawa K, Hishitani T, Isobe T, Etoh Y (2006)
Successful uses of magnesium sulfate for torsades de pointes in
children with long QT syndrome. Pediatr Int 48:112–117
10. Hoshino K, Ogawa K, Hishitani T, Isobe T, Eto Y (2004) Optimal
administration dosage of magnesium sulfate for torsades de
pointes in children with long QT syndrome. J Am Coll Nutr 23:
497–500
11. Maron BJ, Towbin JA, Thiene G et al (2006) Contemporary
definitions and classification of the cardiomyopathies: an Amer-
ican Heart Association Scientific Statement from the Council on
Clinical Cardiology, Heart Failure and Transplantation Com-
mittee; Quality of Care and Outcomes Research and Functional
Genomics and Translational Biology Interdisciplinary Working
Groups; and Council on Epidemiology and Prevention. Circula-
tion 113:1807–1816
12. McNair WP, Ku L, Taylor MR et al (2004) SCN5A mutation
associated with dilated cardiomyopathy, conduction disorder, and
arrhythmia. Familial Cardiomyopathy Registry Research Group.
Circulation 110:2163–2167
13. Mendoza A, Belda S, Salguero R, Granados MA (2010) Con-
genital complete atrioventricular block associated with QT pro-
longation: description of a patient with an unusual outcome.
Pediatr Cardiol 31:887–890
14. Ogawa K, Nakamura Y, Terano K, Ando T, Hishitani T, Hoshino
K (2009) Isolated noncompaction of the ventricular myocardium
associated with long QT syndrome: a report of 2 cases. Circ J
73:2169–2172
15. Pignatelli RH, McMahon CJ, Dreyer WJ et al (2003) Clinical
characterization of left ventricular noncompaction in children: a
relatively common form of cardiomyopathy. Circulation 108:
2672–2678
16. Ritter M, Oechslin E, Sutsch G, Attenhofer C, Schneider J, Jenni
R (1997) Isolated noncompaction of the myocardium in adults.
Mayo Clin Proc 72:26–31
17. Salerno JC, Chun TU, Rutledge JC (2008) Sinus bradycardia,
Wolff–Parkinson–White, and left ventricular noncompaction: an
embryologic connection? Pediatr Cardiol 29:679–682
18. Silver ES, Liberman L, Chung WK (2009) Long QT syndrome
due to a novel mutation in SCN5A: treatment with ICD place-
ment at 1 month and left cardiac sympathetic denervation at
3 months of age. J Interv Card Electropysiol 26:41–45
19. Stephenson EA, Batra AS, Knilans TK (2006) A multicenter
experience with novel implantable cardioverter defibrillator
configurations in the pediatric and congenital heart disease pop-
ulation. J Cardiovasc Electrophysiol 17:41–46
20. Tester DJ, Ackerman MJ (2011) Genetic testing for potentially
lethal, highly treatable inherited cardiomyopathies/channelo-
pathies in clinical practice. Circulation 123:1021–1037
21. Thøgersen AM, Helvind M, Jensen T, Andersen JH, Jacobsen JR,
Chen X (2001) Implantable cardioverter defibrillator in a
4 month-old infant with cardiac arrest associated with a vascular
heart tumor. Pacing Clin Electrophysiol 24:1699–1700
22. Wang DW, Viswanathan PC, Balser JR, George AL Jr, Benson
DW (2002) Clinical, genetic, and biophysical characterization of
SCN5A mutations associated with atrioventricular conduction
block. Circulation 105:341–346
23. Weiford BC, Subbarao VD, Mulhern KM (2004) Noncompaction
of the ventricular myocardium. Circulation 109:2965–2971
24. Zaragoza MV, Arbustini E, Narula J (2007) Noncompaction of
the left ventricle: primary cardiomyopathy with an elusive
genetic etiology. Curr Opin Pediatr 19:619–627
Pediatr Cardiol (2013) 34:189–193 193
123