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\begin{document}

\title{Right Atrial Mass in a Patient With COVID-19 Pneumonia: a case report}



\author[1]{Fahmi  Othman}%
\author[1]{Abdul Rehman  Abid}%
\author[1]{Sabir  Abdulkarim}%
\author[1]{Mohamad  Khatib}%
\author[1]{Abdulqadir Nashwan}%
\author[1]{Maryam  Alkuwari}%
\author[1]{Abdulwahid  AlMulla}%
\author[1]{Awad Alqahtani}%
\affil[1]{Hamad Medical Corporation}%


\vspace{-1em}



  
  \date{June 18, 2024}


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\selectlanguage{english}
\begin{abstract}
Lipomatous hypertrophy of the interatrial septum (LHIAS) is a benign
cardiac tumor. Differential diagnosis of LHIAS consists of atrial masses
such as myxomas or lipomas. Herein, we report a 66-year-old male,
admitted as a case of severe COVID-19 and was found to have a LHIAS
extending to the crista terminalis.%
\end{abstract}%



\sloppy


\textbf{Right Atrial Mass in a Patient With COVID-19 Pneumonia: a case
report}

Fahmi Othman\textsuperscript{1}, Abdul Rehman Abid\textsuperscript{1},
Sabir Abdulkarim\textsuperscript{1}, Mohamad Y.
Khatib\textsuperscript{2}, Abdulqadir J. Nashwan\textsuperscript{4},
Maryam Alkuwari\textsuperscript{3}, Abdulwahid
AlMulla\textsuperscript{1}, Awad Alqahtani\textsuperscript{1}

\textsuperscript{1}Department of Cardiology and Cardiovascular Surgery,
Heart Hospital, Hamad Medical Corporation, \textsuperscript{2} Critical
Care and Pulmonary Medicine, Hamad Medical
Corporation,\textsuperscript{3}Department of Radiology, Hamad Medical
Corporation,\textsuperscript{4}Departement of Nursing Education and
Research, Hamad Medical Corporation, Doha, Qatar.

Corresponding author:

Mr. Abdulqadir J. Nashwan

anashwan@hamad.qa

Tel: (+974) 40240487

Mob: (+974) 66473549

P.O.Box 3050 Doha, Qatar

\textbf{ABSTRACT}

Lipomatous hypertrophy of the interatrial septum (LHIAS) is a benign
cardiac tumor. Differential diagnosis of LHIAS consists of atrial masses
such as myxomas or lipomas. Herein, we report a 66-year-old male,
admitted as a case of severe COVID-19 and was found to have a LHIAS
extending to the crista terminalis.

\textbf{Keywords:} Lipomatous hypertrophy; interatrial septal
hypertrophy; COVID-19; Atrial mass; benign cardiac tumor.

\textbf{Key Clinical Message:}

Lipomatous hypertrophy of the interatrial septum can have an atypical
appearance by transthoracic echocardiography. The authors emphasize on
the importance of the multimodality imaging approach to reach the
appropriate diagnosis in such cases.

\textbf{BACKGROUND}

Lipomatous hypertrophy of the interatrial septum (LHIAS) is a
well-described benign cardiac tumor. LHIAS is a quite frequent finding
seen by echocardiography. It is estimated to be presented in up to 8\%
of the general population. (1)

LHIAS is typically diagnosed by Transthoracic echocardiography (TTE).
However, in some cases, it may have an atypical appearance by TTE,
especially when the echo images are suboptimal.

Differential diagnosis consists of atrial masses such as myxomas or
lipomas.(2)

Interatrial septum thickness of 6 mm in the general population and 7mm
in the elderly are considered normal.(3) Lipomatosis has been defined as
a thickness greater than 15 mm.(4) Adipose tissue can also accumulate in
sub epicardium, crista terminalis, endocardium, and the mediastinum.

\textbf{CASE PRESENTATION}

This is a case of a 66-year-old man with a previous history of
hypertension, diabetes, chronic kidney disease, and psoriasis. He
presented to the communicable disease center (CDC) with a three-day
history of fever, cough, and shortness of breath. On admission, his
vital signs were as follows: blood pressure:115/52mmHg, heart rate: 75
b/min, respiratory rate: 20 b/min, and oxygen saturation
(O\textsubscript{2}sat): 93\% on room air. His body mass index (BMI) was
29 kg/m\textsuperscript{2}. Physical examination was remarkable for
bilateral chest crackles with normal cardiovascular examination.

His electrocardiogram (ECG) revealed a sinus rhythm with right bundle
branch block (RBBB) and left axis deviation. Chest x-ray showed patchy
peripheral ground-glass opacities in both lungs and soft consolidations
in the right middle lobe. Polymerase chain reaction (PCR) was performed
on a nasopharyngeal swab and returned positive for SARS-CoV-2. In
addition, blood tests showed WBC of 5.9 x10\^{}3/uL, hemoglobin of 10
gm/dL(N\{13-17 gm/dL\}), C-reactive protein (CRP) of 146 mg/L {[}N
\textless{} 6 mg/L{]}), ferritin of 2619 ug/L {[}N \textless{} 553
ug/L{]}), creatinine of 190 umol/L (N\{62-106 umol/L), and D Dimer of
2.3 mg/L FEU {[}N \textless{} 0.5 mg/L FEU{]}).

He was started on oxygen therapy at 2 liters per minute via nasal
cannula, but shortly after admission, he became severely hypoxic, and
then, he was transferred to the medical intensive care unit (MICU) and
kept on continuous positive airway pressure (CPAP) to maintain oxygen
saturation of 95\%.

Transthoracic echocardiography (TTE) was performed, which revealed
normal biventricular size and function with no significant valvular
disease. Mild pulmonary hypertension with an estimated systolic
pulmonary artery pressure of 48mmHg was noted. The study showed echo
dense mass located on the right atrial (RA) roof, best seen in
four-chamber view. There was another echo-lucent mass in the RA and
protruding into the tricuspid valve annulus, best seen in the RV inflow
view, as shown in (Figure 1). A prior TTE report that had been performed
in another center one month ago revealed no interatrial mass.

Because of acute COVID-19 pneumonia and elevated D-dimer, the RA mass
was considered and treated as a thrombus. He was started on a
therapeutic dose of intravenous heparin and warfarin; thus, the INR was
maintained in the therapeutic range between 2 to 3. Repeated echo did
not show any significant differences. For a better assessment of the RA
mass, Transesophageal echocardiography (TEE) was planned, but was not
performed due to acute respiratory distress with low oxygen saturation.
Instead, 12 days later, upon clinical recovery a cardiac magnetic
resonance imaging (CMR) was performed.

The images were obtained on a 1.5 Tesla scanner (Philips Ingenia), and
findings from the multiple stacks of cine four-chamber views confirmed
the presence of a structure on the posterior wall of the RA that extends
onto the thickened interatrial septum (Figure 2). This smooth structure
moved during systole and diastole and was identified as crista
terminalis, which was rather prominent. T1 and T2 weighted images on the
axial plane of this structure had a similar signal intensity to the
subcutaneous fat revealing it as predominantly fatty deposition. T1
weighted images with fat saturation sequences (Figure 3) demonstrated
the suppression of fatty signals consistent with LHIAS of the thickened
interatrial septum associated with fatty deposition in the crista
terminalis. On post gadolinium, early and late acquisition, there were
no uptake or features to suggest the presence of thrombus or any other
cardiac tumors (Figure 4).

CMR concluded that the prominent RA mass was lipomatosis hypertrophy of
the interatrial septum, which extends to the crista terminalis with no
evidence of any thrombus. Hence the anticoagulation was discontinued,
and patient was discharged home in very good condition.

\textbf{DISCUSSION}

Lipomatous hypertrophy of the interatrial septum (LHIAS) is usually
incidental and typically diagnosed by a transthoracic echocardiogram
(TTE) by appreciating the classic dumbbell-shaped morphology within the
interatrial septum.(5) However, an atypical appearance on TTE might
happen; therefore, multimodality imaging is required to confirm the
diagnosis of LHIAS.

LHIAS typically spares the fossa ovalis while respecting the atrial
septum boundaries.(6) TTE has low sensitivity in diagnosing LHIAS due to
limited resolution, especially when the image quality is suboptimal. A
transesophageal echocardiogram can be used to easily make the diagnosis
for LHIAS, which best appears `in the bicaval view' as ``globular
thickening of the interatrial septum''.

What made matters worse was that this mass was incidentally discovered
in this patient with COVID-19 pneumonia. As has been published in
several studies, accelerated thrombosis was frequently reported in
patients admitted with COVID-19. Therefore, in our case, due to severe
Covid-19 symptoms with elevated D-dimer, the mass was treated as an
intracardiac thrombus; initially, heparin and warfarin, then
subsequently with warfarin only using a target INR between 2-3.

Due to the patient's acute respiratory distress, he was not suitable for
any intervention. Therefore, the decision was made not to proceed with
TEE to prevent further respiratory deterioration.

Typically, the borders of cardiac tumors are determined by CMR. It also
offers a superior tissue characterization. LHIAS follow the same signal
intensity of subcutaneous fat (7). Sparing the fossa ovalis and
extension of greater than 2cm in transverse diameter are unique to LHIAS
that differentiates it from lipomas. Typical findings include uniform
high signal intensity on T1 and T2 weighted images with signal
suppression on fat-saturated images.(8) They appear hyperintense also on
SSFP cine sequences, with no gadolinium contrast enhancement neither on
the first-pass perfusion nor in the delayed phase.(9) Other differential
here with fatty content would be malignant masses, which demonstrates
infiltration of anatomic structures, poor definition of borders,
inhomogeneous tissue appearance post gadolinium, and associated
pericardial or pleural effusion.(10) Thus localization, morphology, and
signal intensity tissue characterization on the CMR helps differentiate
between etiologies of tumors in the heart.

\textbf{CONCLUSION}

This case highlights the importance of understanding RA anatomy, as well
as the limitations of TTE, especially in patients with suboptimal image
quality. It has also confirmed the importance of the multimodality
imaging approach to reach the appropriate diagnosis in such cases.

\textbf{Abbreviations}

COVID-19: Coronavirus disease

PCR: Polymerase chain reaction

CMR: Cardiac Magnetic Resonance Imaging

LHIAS: Lipomatous hypertrophy of the interatrial septum

TTE: Transthoracic echocardiography

CPAP: Continuous Positive Airway Pressure

\textbf{Declarations}

\textbf{Ethics approval and consent to participate}

The article describes a case report. Therefore, no additional permission
from our Ethics Committee was required.

\textbf{Consent for publication}

The consent for publication was obtained.

\textbf{Availability of data and material}

All data generated or analyzed during this study are included in this
published article.

\textbf{Competing interests}

The authors declare that they have no competing interests.

\textbf{Funding}

This study was not funded.

\textbf{Authors' contributions}

FO, ARA, SA, MYK, AJN, MA, AAM, AAQ: Data Collection, Literature Search,
Manuscript Preparation

All authors read and approved the final manuscript

\textbf{Acknowledgments}

Open Access funding provided by the Qatar National Library.

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3. Rigatelli G, Dell'Avvocata F, Braggion G, Giordan M, Chinaglia M,
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