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\begin{document}

\title{Do we really need a new classification for cor triatriatum sinister?}



\author[1]{Alhanouf Alaloola}%
\author[1]{Rawan Alghamdi}%
\author[2]{Amr Arafat}%
\affil[1]{Affiliation not available}%
\affil[2]{Tanta University Faculty of Medicine}%


\vspace{-1em}



  
  \date{June 17, 2024}


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\begin{abstract}
Current classifications of Cor Triatriatum Sinister (CTS) do not address
the associated heart defects or single ventricle pathology. Therefore,
these classifications are not prognostic classifications and only
describe the anatomy and the pulmonary venous drainage. The proposed
classification considered the associated congenital cardiac lesions and
the single ventricle pathology, therefore, it could have prognostic
value. Future multicenter studies are required to measure the
performance of this classification and its prognostic value in patients
with CTS.%
\end{abstract}%



\sloppy


\textbf{Do we really need a new classification for cor triatriatum
sinister?}

Alhnouf A. Alaloola, MD (1), Rawan Alghamdi, MD (2), Amr A. Arafat, Ph.D
(2, 3)

\begin{enumerate}
\tightlist
\item
  King Fahd Medical City- Riyadh- Saudi Arabia
\item
  Prince Sultan Cardiac Center- Riyadh- Saudi Arabia
\item
  Cardiothoracic Surgery, Tanta University, Tanta, Egypt
\end{enumerate}

\textbf{Running title:} cor triatriatum classifications

\textbf{Word count:} a total of 1000

\textbf{Number of references:} 15

\textbf{Conflict of interest:} None

\textbf{Funding:} None

\textbf{Corresponding author:}

Amr A. Arafat, MD, Ph.D.

Correspondence Amr A. Arafat, MD, Department of Adult Cardiac Surgery,
Prince Sultan Cardiac Center, Building 6, Makkah Al Mukarramah Branch
Road, As Sulimaniyah, Riyadh 12233, Saudi Arabia.

Email: amr.arafat@med.tanta.edu.eg

\textbf{Do we really need a new classification for cor triatriatum
sinister?}

We have read with great interest the manuscript written by Mashadi and
colleagues, ''Cor Triatriatum Sinister: Long-term Surgical Outcomes in
Children and a Proposal for a New Classification. (1)'' Cor triatriatum
sinistrum (CTS) is a rare cardiac congenital malformation and represents
around 0.1-0.4\% of all congenital heart defects, with a very limited
number of cases reported in the literature (2, 3). CTS describes an
anomaly where the left atrium is subdivided by a thin membrane resulting
in two chambers. Many classifications have been used to describe CTS;
the most commonly used are the Loeffler's, Lam's, and Lucas's, which are
mainly anatomical.

Loffler's classification was developed in 1949, and it depends on the
size and number of fenestrations communicating the two atrial chambers.
In Loffler's classification, group 1 has no connection between the two
chambers, and group 3 has free communication between the two chambers
(4). Later in 1962, Lam's classification came to elaborate more on the
morphological features of CTS, including pulmonary venous drainage and
the site of the atrial septal defect (5). Lucas' classification added
further anatomical details and described the association between CTS and
anomalous drainage of the pulmonary veins, which the Society of Thoracic
Surgeons project adapted for Congenital Heart Surgery Nomenclature and
Database (6). Other uncommon classifications described the anatomical
features of the accessory left atrial chamber and membrane (7) or the
entry of the pulmonary veins into the accessory chamber (8).

The current classifications do not describe the complex nature and
possible presentation of CTS that may affect long-term outcomes. Lam's
classification takes into consideration the location of drainage of the
pulmonary veins and if there is an atrial septal defect (ASD) or not.
However, it does not consider the number and size of communication
between the two chambers (9, 10). CTS can be associated with other
cardiac anomalies in up to 80\% of the cases; the most commonly
associated cardiac anomalies are atrial septal defect~(ASD) in around
60\% of patients (11, 12) and partial or total anomalous
pulmonary~venous return, which has been reported in nearly one-third of
the patients with CTS (13). Several studies showed the association of
CTS with other congenital anomalies, such as bicuspid aortic valve,
atrioventricular canal, tetralogy of Fallot and ventricular septal
defect (1, 14). The early and long-term outcomes may vary according to
the associated congenital cardiac defects, and in the previously
mentioned classifications, a full range of associated congenital heart
defects was not taken into consideration.

Additionally, Nagao and colleagues found better survival in CTS patients
who had biventricular repair compared to the univentricular pathway
(15). Obviously, the univentricular heart was not considered in the
previous CTS classifications despite the reported worse outcomes in this
category. Furthermore, the exact surgical approach is chosen primarily
based on the presence of associated lesions and the size of the atria.
The proposed classification mainly depends on the possible presentations
and potentially addresses the long-term outcome (1). Mashadi and
colleagues divided the patients into three groups: isolated without
other congenital heart defects, in association with single ventricle
physiology, and CTS concomitant with other congenital heart defects.
This proposed classification addresses the anatomical factors previously
presented in older classifications, in addition to the associated heart
defects and single ventricle pathology. The outcomes could differ in
each group; therefore, this proposed classification could have a
prognostic value and can anticipate the possible outcomes for each
group.

This classification seems beneficial in underlining the anatomical and
pathophysiological presentation of CTS; however, its value is still
limited, pending a multicenter study or a pooled analysis with a larger
sample size to correlate the outcomes of CTS with each classification
category.

\textbf{Reference:}

\begin{enumerate}
\tightlist
\item
  Mashadi A, Narasimhan S, and Said S. Cor Triatriatum Sinister:
  Long-term Surgical Outcomes in Children and a Proposal for a New
  Classification. J of Card Surg, in press.
\item
  Nassar PN, Hamdan RH. Cor Triatriatum Sinistrum: Classification and
  Imaging Modalities. Eur J Cardiovasc Med. 2011 Jan;1(3):84-87. doi:
  10.5083/ejcm.20424884.21. PMID: 22379596; PMCID: PMC3286827.
\item
  Wolf WJ. Diagnostic features and pitfalls in the two-dimensional
  echocardiographic evaluation of a child with cor triatriatum. Pediatr
  Cardiol. 1986;6(4):211-3. doi: 10.1007/BF02311001. PMID: 3703693.
\item
  Loeffler E. Unusual malformation of the left atrium: Pulmonary sinus.
  Arch Pathol (Chic). 1949Nov; 48(5):371--6.
\item
  Lam CR, Green E, Drake E. Diagnosis and surgical correction of 2 types
  of triatrial heart. Surgery. 1962;51:127-13
\item
  Herlong JR, Jaggers JJ, Ungerleider RM. Congenital Heart Surgery
  Nomenclature and Database Project: pulmonary venous anomalies. Ann
  Thorac Surg. 2000;69:S56-S69.
\item
  Marin-Garcia J, Tandon R, Lucas RV Jr, Edwards JE. Cor triatriatum:
  study of 20 cases. Am J Cardiol. 1975;35:57-66.
\item
  Rodefeld MD, Brown JW, Heimansohn DA, et al. Cor triatriatum: clinical
  presentation and surgical results in 12 patients. Ann Thorac Surg.
  1990;50:562-568.
\item
  Humpl T, Reineker K, Manlhiot C, Dipchand AI, Coles JG, McCrindle BW.
  Cor triatriatum sinistrum in childhood. A single institution's
  experience.~\emph{Can J Cardiol} . 2010;26(7):371-376.
  doi:10.1016/s0828-282x(10)70418-9
\item
  Alphonso N, N\selectlanguage{ngerman}ørgaard MA, Newcomb A, d'Udekem Y, Brizard CP, Cochrane
  A. Cor triatriatum: presentation, diagnosis and long-term surgical
  results. Ann Thorac Surg. 2005 Nov;80(5):1666-71. doi:
  10.1016/j.athoracsur.2005.04.055. PMID: 16242436.
\item
  Al Qethamy HO, Aboelnazar S, Al Faraidi Y, Al Jubair K, Gadura M,
  Fagih M. Cor triatriatum: operative results in 20 patients. Asian
  Cardiovasc Thorac Ann. 2006 Feb;14(1):7-9. doi:
  10.1177/021849230601400103. PMID: 16432110.
\item
  Oglietti J, Cooley DA, Izquierdo JP, Ventemiglia R, Muasher I, Hallman
  GL, Reul GJ Jr. Cor triatriatum: operative results in 25 patients. Ann
  Thorac Surg. 1983 Apr;35(4):415-20. doi:
  10.1016/s0003-4975(10)61594-9. PMID: 6188419.
\item
  Clemente A, Viganò G, Federici D, Calabri GB, Pak V. Cor triatriatum
  sinister with unusual pulmonary venous return. Eur Heart J Case Rep.
  2022 Mar 9;6(3):ytac108. doi: 10.1093/ehjcr/ytac108. PMID: 35295089;
  PMCID: PMC8922682.
\item
  Ozyuksel A, Yildirim O, Avsar M, et al. Surgical correction of cor
  triatriatum sinister in the paediatric population: mid-term results in
  15 cases.~\emph{Eur J Cardiothorac Surg} . 2015;47(1):e25-e28.
  doi:10.1093/ejcts/ezu390
\item
  Nagao H, Tanaka T. Mid-term outcomes of cor triatriatum repair:
  comparison of biventricular physiology and univentricular
  physiology.~\emph{Cardiol Young} . 2021;31(2):186-190.
  doi:10.1017/S1047951120003595
\end{enumerate}

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