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\begin{document}

\title{Endocardial pacing in a single-ventricle patient with tricuspid atresia-
a case report}



\author[1]{Ahmad  Yamini-Sharif}%
\author[1]{Ramin Yaghoubian}%
\author[1]{Homa  Ghaderian}%
\author[1]{Najme-Sadat  Moosavi}%
\affil[1]{Tehran Heart Center}%


\vspace{-1em}



  
  \date{May 25, 2024}


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\begin{abstract}
The use of endocardial pacing in patients with univentricular hearts is
limited. However, it may be the better option when the risk of surgery
is high. We report a case of complete heart block who underwent left
ventricular endocardial pacing due to the high risk of epicardial lead
placement.%
\end{abstract}%



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Title Page

A) Title: Endocardial pacing in a single-ventricle patient with
tricuspid atresia- a case report

B) Authors:

1) Ahmad Yamini-Sharif\textsuperscript{1} (first author),
ahmadyaminisharif@yahoo.com

2) Ramin Yaghoubian\textsuperscript{1} (corresponding author),
ramin.yaghoubian@gmail.com

3) Homa Ghaderian\textsuperscript{1}, homaghaderian@gmail.com

4) Najme-Sadat Moosavi\textsuperscript{1}, ns.moosavi@yahoo.com

\textsuperscript{1}Cardiology Department, Tehran Heart Center, Tehran
University of Medical Sciences, Tehran, Iran

C) Correspondence to: Ramin Yaghoubian. Address: Department of
Cardiology, Tehran Heart Center, Tehran University of Medical Sciences,
North Kargar Avenue, Tehran, Iran.

Email address: ramin.yaghoubian@gmail.com /
https://orcid.org/0000-0003-1723-157X

\textbf{ABSTRACT}

The use of endocardial pacing in patients with univentricular hearts is
limited. However, it may be the better option when the risk of surgery
is high. We report a case of complete heart block who underwent left
ventricular endocardial pacing due to the high risk of epicardial lead
placement.

\textbf{KEYWORDS}

Univentricular hearts, Transvenous pacing, Epicardial pacing, Tricuspid
atresia, Congenital heart disease, Perirenal fluid

\textbf{1. INTRODUCTION}

Multiple congenital heart diseases have progressive conduction
disorders, either intrinsic or developed through reparative
surgeries.\textsuperscript{1} In particular, univentricular hearts are
more associated with bradyarrhythmias and complete heart block. Many of
these patients need a permanent pacemaker.\textsuperscript{2} In
univentricular hearts, epicardial pacing has been the first option
because of the limited venous access. Also, in the presence of
intracardiac shunts, it is the preferred method since there is an
increased risk of systemic thromboembolism with the endocardial
route.\textsuperscript{1-3} However, epicardial leads have considerable
disadvantages. One of them is that they have higher chronic pacing
thresholds and reduced generator longevity, although this may be
improved with the usage of steroid-eluting epicardial leads. Another
problem is invasive surgeries used for implanting these
leads.\textsuperscript{4,5} The present report explains the implantation
of a permanent endocardial pacemaker in an adult patient with tricuspid
atresia type IIc with severe pulmonary hypertension and complete heart
block.

\textbf{2. CASE PRESENTATION}

A 42 years old man from Iraq with frequent episodes of syncope since one
month ago was admitted to the Tehran heart center hospital. He had a
history of tricuspid atresia type 2c without reparative surgery. On his
admission, the patient had fatigue. On physical examination, he had nail
clubbing and cyanosis with an O2 saturation of 75\%. His
electrocardiogram revealed a complete heart block with a right bundle
branch block (figure 1). Echocardiography showed tricuspid atresia with
transposition of the great arteries (TGA type), severe pulmonary
hypertension (mean of PAP:85mmHg), and dominant left ventricle with
LVEF:35\%. Cardiothoracic CT was done to evaluate better the cardiac
structure, which revealed a large pulmonary trunk, hypoplastic ascending
aorta, aortic arch with large PDA, and interrupted aorta. Detailed
findings of the Cardiothoracic CT scan are shown in figures 2 and 3. In
abdominal CT, an accidental finding was bilateral perirenal fluid
accumulation (figure 4).

The risk of the surgery for the epicardial lead placement was high due
to pulmonary hypertension; on the other hand, the transvenous pacing
would increase the risk of systemic thromboembolism. We discussed the
risk associated with each procedure with the patient and recommended the
endocardial route, which he accepted. Thus, endocardial pacemaker
implantation was scheduled for the patient. After prep and drape, local
anesthesia and light sedation were conducted. The left subclavian vein
access was gained, and a dual-chamber rate-modulated (DDDR) permanent
pacemaker was implanted using a peel-away introducer. Atrial lead was
inserted in the right atrial auricle. Ventricular lead was advanced
through the atrial septal defect and mitral valve and was placed in the
common ventricle. The patient was on heparin during the procedure, and
lifelong warfarin was initiated for the patient 24 hours after the
surgery. On follow-up, the patient was well and had no complaints. The
pacemaker was in the proper position without clot formation. The
post-pacing electrocardiogram is shown in figure 1.

\textbf{3. DISCUSSION}

Epicardial pacing has been a regular option for patients with complex
congenital heart disease. Epicardial leads may be placed during cardiac
surgery for underlying congenital heart disease with a plan to replace
them in the future with transvenous leads.\textsuperscript{4}Endocardial
pacing of the ventricle for patients with Fontan circulation was
impractical due to the lack of transvenous access to the ventricle. With
the advances in pacing techniques, ventricular pacing in these patients
is possible. Hsieh et al. reported permanent pacing of the left
ventricle via coronary sinus in a patient with Fontan circulation and
complete atrioventricular (AV) block.\textsuperscript{6} In another case
report of a single ventricle patient using the endocardial method,
DeWitt et al. described successfully placing a ventricular pacing lead
through a trans-Fontan-baffle puncture.\textsuperscript{7} These
techniques may be good alternatives to high-risk epicardial pacing
methods in this group of patients.

Endocardial ventricular pacing is technically possible in patients with
univentricular hearts who have not had previous reconstructive surgery,
but the higher risk for thromboembolism limits this
procedure.\textsuperscript{2} In a cohort study of 202 patients,
transvenous pacemakers increased the risk of systemic thromboembolism in
patients with intracardiac shunt by \textgreater{}2-fold, and
anticoagulant therapy with warfarin or aspirin did not reduce the
risk.\textsuperscript{3} However, when the risk of the surgery for
epicardial lead placement is high transvenous route may be the better
choice. This case was a candidate for a Fontan procedure with epicardial
lead placement, but this was a high-risk procedure considering his
chronic high pulmonary artery pressure. As a result, we deemed that
transvenous lead placement with a tight anticoagulant regimen is the
option with the lower risk. According to our research, this is the
second report of left ventricular endocardial pacing via the interatrial
septum in a single ventricle patient. In a similar study, Scott et al.
reported a case of tricuspid atresia with intracardiac shunt and
symptomatic chronotropic incompetence. They implanted an endocardial
pacemaker in his left ventricle through the atrial septal defect to
improve his condition. The patient had no thromboembolic events or
complications related to the procedure at the one-year
follow-up.\textsuperscript{8}

There are few studies comparing the outcomes of dual-chamber pacing
versus single-chamber ventricular pacing in patients with single
ventricle physiology. Nevertheless, dual-chamber pacemakers are
generally considered in these patients because of atrioventricular
synchrony, which enhances cardiac output and the capacity to interfere
if atrial arrhythmia or sick sinus syndrome occurs.\textsuperscript{9}

The bilateral perirenal fluid accumulation was a rare finding in the
present case. It has been reported in cases with intracardiac shunt and
pulmonary hypertension.\textsuperscript{10,11} Pentimone et al. proposed
that the underlying mechanism is that pulmonary hypertension increases
local hydrostatic pressure in the perirenal veins, leading to fluid
leakage to the renal subcapsular space. In their case repeated
phlebotomies lowerd hematocrit and reduced perirenal fluid
significantly.\textsuperscript{10}

In conclusion, while endocardial pacing, in the presence of intracardiac
shunts, has the risk of systemic thromboembolism, it may be the safer
alternative for epicardial interventions in selected patients.

\textbf{AUTHOR CONTRIBUTIONS}

AYS was involved in patient management and supervised the case report.
RY undertook a comprehensive literature review and wrote the manuscript.
HG was involved in patient management and manuscript preparation. NSM
provided the images and contributed to their interpretation of them. All
authors critically revised and approved the final manuscript.

\textbf{ACKNOWLEDGMENTS}

We wish to thank the patient for his consent to the publication of the
data.

\textbf{FUNDING INFORMATION}

None

\textbf{CONFLICT OF INTEREST}

The authors declare that they have no conflicts of interest.

\textbf{DATA AVAILABILITY STATEMENT}

Data sharing does not apply to this article as no new data were created
or analyzed in this study.

\textbf{ETHICAL APPROVAL}

Ethical approval for this case report was not required.

\textbf{CONSENT}

Written informed consent was obtained from the patient for the
publication of this report.

\textbf{REFERENCES}

1. McLeod CJ, Attenhofer Jost CH, Warnes CA, et al. Epicardial versus
endocardial permanent pacing in adults with congenital heart disease. J
Interv Card Electrophysiol 2010;28(3):235-43.

2. Umamaheshwar KL, Singh AS, Sivakumar K. Endocardial transvenous
pacing in patients with surgically palliated univentricular hearts: A
review on different techniques, problems and management. Indian Pacing
Electrophysiol J 2019;19(1):15-22.

3. Khairy P, Landzberg MJ, Gatzoulis MA, et al. Transvenous pacing leads
and systemic thromboemboli in patients with intracardiac shunts: a
multicenter study. Circulation 2006;113(20):2391-7.

4. Fortescue EB, Berul CI, Cecchin F, Walsh EP, Triedman JK, Alexander
ME. Comparison of modern steroid-eluting epicardial and thin transvenous
pacemaker leads in pediatric and congenital heart disease patients. J
Interv Card Electrophysiol 2005;14(1):27-36.

5. Beaufort-Krol GC, Mulder H, Nagelkerke D, Waterbolk TW, Bink-Boelkens
MT. Comparison of longevity, pacing, and sensing characteristics of
steroid-eluting epicardial versus conventional endocardial pacing leads
in children. J Thorac Cardiovasc Surg 1999;117(3):523-8.

6. Hsieh MJ, Yeh KH, Satish OS, Wang CC. Permanent pacing using a
coronary sinus lead in a patient with univentricular physiology: an
extended application of biventricular pacing technology. Europace
2006;8(2):147-50.

7. DeWitt E, Callahan R, Blume E, Marshall A, Mah D. Trans-Fontan baffle
placement of an endocardial systemic ventricular pacing lead.
HeartRhythm Case Rep 2017;3(2):129-32.

8. Scott PA, Veldtman GR, Yue AM, Morgan JM. Permanent transvenous left
ventricular endocardial pacing in a patient with univentricular
atrioventricular connection. Congenit Heart Dis 2011;6(5):475-8.

9. Idriss SF, Weiland MD. Ventricular Pacing in Single Ventricle
Circulation: Making the Best of a Difficult Situation. J Am Coll Cardiol
2022;80(9):915-17.

10. Pentimone F, Meola M, Del Corso L. Bilateral perinephric fluid
accumulation: an unusual manifestation of pulmonary hypertension--a case
report. Angiology 1993;44(6):500-5.

11. P\selectlanguage{ngerman}ölzl G, Lhotta K, Tiefenthaler M, Smekal A, Müller S. Bilateral
perirenal fluid accumulation associated with Eisenmenger's syndrome.
Nephrol Dial Transplant 2004;19(7):1928-9.

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