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Table of Contents   
Year : 2012  |  Volume : 5  |  Issue : 1  |  Page : 92-94
Cor triatriatum dexter: A rare cause of childhood cyanosis

Paediatric Cardiology Unit, Department of Cardiology, Penang Hospital, Jalan Residensi, Penang, Malaysia

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Date of Web Publication12-Mar-2012


Cor triatriatum dexter is a rare congenital heart anomaly where the right atrium is divided into two chambers by a membrane. We report a boy who had persistent mild cyanosis and diagnosed to have cor triatriatum dexter with secundum atrial septal defect by transoesophageal echocardiography. Interestingly, he had persistent mild cyanosis despite insignificant obstruction to the right ventricular inflow and normal pulmonary artery pressure. The pathophysiology, approach to the diagnosis, and mode of treatment are also discussed.

Keywords: Atrial septal defect, cor triatriatum dexter, cyanosis, transoesophageal echocardiography

How to cite this article:
Mohd Zainudin AR, Tiong KG, Mokhtar SA. Cor triatriatum dexter: A rare cause of childhood cyanosis. Ann Pediatr Card 2012;5:92-4

How to cite this URL:
Mohd Zainudin AR, Tiong KG, Mokhtar SA. Cor triatriatum dexter: A rare cause of childhood cyanosis. Ann Pediatr Card [serial online] 2012 [cited 2021 Oct 19];5:92-4. Available from:

   Introduction Top

Cor triatriatum dexter, or partitioning of the right atrium (RA) to form a triatrial heart, is an extremely rare congenital anomaly that is caused by the persistence of the right valve of the sinus venosus. [1] The incidence of cor triatriatum is approximately 0.1% of congenital heart malformation. [2] Typically, the right atrial partition is due to exaggerated fetal eustachian and thebesian valves, which together form an incomplete septum across the lower part of the atrium. This septum may range from a reticulum to a substantial sheet of tissue. [1]

   Case Report Top

A 9-year-old boy was admitted to a local district hospital for pneumonia. After one week of treatment with antibiotics, he was asymptomatic and there was no more sign of respiratory distress. However, his oxygen saturation persistently ranged from 88 to 92%. Initial transthoracic echocardiography (TTE) showed a structurally normal heart. He was referred to our hospital for further assessment. Clinically, he had mild cyanosis. Other clinical examination including the cardiovascular system examination was unremarkable. Evaluation with TTE showed a normal heart anatomy. However, contrast echocardiography demonstrated a right-to-left shunting at the atrial level. Subsequently, a transesophageal echocardiography (TEE) showed a membrane across right atrium [Figure 1] without causing obstruction to right ventricular inflow [Figure 2]. There was also an anterior secundum atrial septal defect (ASD) and the bubble study showed an immediate right-to-left shunting through the ASD [Figure 3]. His cardiac catheterization showed a normal hemodynamic study. Two months later, surgical resection of the cor triatriatum dexter membrane and patch closure of ASD were performed. Postoperative echocardiography showed the minimal residual membrane of the cor triatriatum dexter with no residual ASD shunting. Clinically, he remained asymptomatic and his saturation improved to >95%.
Figure 1: 2D transoesophageal echocardiography apical four chamber view showing presence of a membrane separating the right atrium into two parts

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Figure 2: The blood flow to the right ventricle was not obstructed by the membrane

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Figure 3: Contrast echocardiography showed an immediate right-to-left shunting through the secundum atrial septal defect

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   Discussion Top

During embryogenesis, the right horn of the sinus venosus gradually incorporates into the right atrium to form the smooth posterior portion of the right atrium, whereas the original embryologic right atrium forms the trabeculated anterior portion. The connection between the right horn of the sinus venosus and the embryologic right atrium is the sinoatrial orifice, which is flanked on either side by two valvular folds, the right and left venous valves. At some point during this incorporation, the right valve of the right horn of the sinus venosus divides the right atrium into two. This right valve forms a sheet that serves to direct the oxygenated venous return from the inferior vena cava across the foramen ovale to the left side of the heart during the fetal life. [1] Normally, the valve regresses by approximately 12 weeks gestation and leaves behind the crista terminalis superiorly and the eustachian valve of the inferior vena cava and the thebesian valve of the coronary sinus inferiorly. Complete persistence of the right sinus valve results in a separation between the smooth and trabeculated portions of the right atrium, constituting cor triatriatum dexter. [3]

Unlike cor triatriatum sinister, which carries a high mortality rate if not repaired, cor triatriatum dexter has varying clinical manifestations depending on the degree of partitioning or septation of the right atrium. When the septation is mild, the condition is often asymptomatic and is an incidental finding during surgery to correct other cardiac abnormalities or during echocardiography. More severe septation can cause right-sided heart failure and elevated central venous pressures due to obstruction of the tricuspid valve, the right ventricular outflow tract, or the inferior vena cava. [1] Cor triatriatum dexter can occur as an isolated cardiac anomaly or associated with other malformation of right heart structures such as pulmonary artery stenosis or atresia, tricuspid valve abnormality, ASD, and Ebstein anomaly. [1],[4] Cyanosis is a very rare presentation of this condition. Hoye and colleagues reported a neonate with cor triatriatum dexter with cyanosis and assessment showed significant obstruction to right ventricular inflow. Most of the flow was directed to the left atrium through a patent foramen ovale. [5] Our patient has an ASD that allows the deoxygenated blood from right atrium to flow across it and mix with oxygenated blood in the left atrium that led to mild degree of cyanosis. Interestingly, this happened despite insignificant flow obstruction to right ventricle and normal pulmonary artery pressure. One possible explanation is that the membrane acts as a venous valve that directs the blood flow from right to left atrium.

Since many patients are asymptomatic, the diagnosis of cor triatriatum dexter often is determined at postmortem examination. Antemortem diagnosis can be determined by using angiography, echocardiography, contrast echocardiography, or MRI. There have been numerous reports about the use of echocardiography to determine the diagnosis noninvasively that mainly date from the mid-1980s to early 1990s. [6],[7] Baweja et al., reported a case in which 3D transesophageal echocardiography was able to detect cor triatriatum dexter in partial atrioventricularseptal defect (AVSD) patient that was missed by 2D echocardiography. [8] In a study in which MRI was compared with echocardiography and cardiac angiography in the evaluation of pulmonary venous anomalies, which included cases of cor triatriatum, MRI had a higher detection rate (95%) than the other modalities (69% for angiography and 38% for echocardiography). [9]

Asymptomatic patients are generally not treated unless they are undergoing cardiac surgery for other reasons. In the past, the mainstay of treatment for symptomatic patients has been surgical resection of the dividing membrane. [2],[3],[4] Our patient underwent surgery to close the ASD and the opportunity was taken to do a resection of the cortriatriatum membrane as well. Recently, percutaneous catheter disruption of the membrane has been reported and has been suggested as a preferred alternative to open heart surgery. [10]

   References Top

1.Embrey RP. Cor triatriatum, pulmonary vein stenosis, atresia of the common pulmonary vein. In: Mavroudis C, Backer CL, editors. Pediatric cardiac surgery. 2 nd ed. St Louis: Mosby-Year Book; 1994. p. 503-4.  Back to cited text no. 1
2.Arrants JE, Riopel DA, Catalano PW. Cor triatriatum: Preoperative diagnosis and successful surgical correction in a ten-week-old infant. Chest 1973;63:1027-8.  Back to cited text no. 2
3.Ott DA, Cooley DA, Angelini P, Leachman RD. Successful surgical correction of symptomatic cor triatriatum dexter. J Thorac Cardiovasc Surg 1979;78:573-5.  Back to cited text no. 3
4.Mazzucco A, Bortolotti U, Gallucci V, Del Torso S, Pellegrino P. Successful repair of symptomatic cor triatriatum dexter in infancy. J Thorac Cardiovasc Surg 1983;85:140-3.  Back to cited text no. 4
5.Hoye DJ, Wilson EC, Fyfe DA, Guzzetta NA. Cor triatriatum dexter: A rare cause of neonatal cyanosis. Anesth Analg 2010;110:716-8.  Back to cited text no. 5
6.Burton DA, Chin A, Weinber PM, Pigott JD. Identification of cor triatriatum dexter by two-dimensional echocardiography. Am J Cardiol 1987;60:409-10.  Back to cited text no. 6
7.Fiorilli R, Argento G, Tomasco B, Serino W. Cor triatriatum dexter diagnosed by transesophageal echocardiography. J Clin Ultrasound 1995;23:502-4.  Back to cited text no. 7
8.Baweja G, Nanda NC, Kirklin JK. Definitive diagnosis of cor triatriatum with common atrium by three-dimensional transesophageal echocardiography in an adult. Echocardiography 2004;21:303-6.  Back to cited text no. 8
9.Masui T, Seelos KC, Kersting-Sommerhoff BA, Higgins CB. Abnormalities of the pulmonary veins: Evaluation with MR imaging and comparison with cardiac angiography and echocardiography. Radiology 1991;181:645-9.  Back to cited text no. 9
10.Savas V, Samyn J, Schreiber TL, Hauser A, O'Neill WW. Cor triatriatum dexter: Recognition and percutaneous transluminal correction. Cathet Cardiovasc Diagn 1991;23:183-6.  Back to cited text no. 10

Correspondence Address:
Ahmad Rustam bin Mohd Zainudin
Paediatric Cardiology Unit, Penang Hospital, Jalan Residensi, 10990 Penang
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Source of Support: None, Conflict of Interest: None

DOI: 10.4103/0974-2069.93725

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  [Figure 1], [Figure 2], [Figure 3]

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