Abstract
Cor triatrium dexter (CTD) is considered a rare congenital heart disease and accounts for 0.1 % of cardiac malformations. This condition occurred due to failure of regression of the right venous valve at the opening of the sinoatrial orifice in the right atrium, dividing the right atrium into 2 parts and forming a tri-atrial heart.
Case presentation: A 7-year-old child presented with fatigue and exertional dyspnea. Examination revealed oxygen saturation of 85 % and an ejection systolic murmur over the pulmonary area. Echocardiography showed moderate valvular pulmonary stenosis and a suspected membrane in the right atrium, while transesophageal echocardiography revealed a high secundum atrial septal defect (ASD) with bidirectional flow and a non-obstructive membrane in the right atrium, CTD. The patient underwent successful surgical closure of the ASD and resection of the CTD, resulting in improved oxygen saturation (98 %) and significant clinical improvement.
Conclusion, Cor triatriatum dexter is a rare congenital cardiac anomaly that can be missed on transthoracic echocardiography despite being a potential cause of central cyanosis.
Highlights
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Cor triatrium dexter is extremely rare congenital cardiac anomaly and is a diagnostic challenge.
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Skilled clinical evaluation of cyanosis and precise echocardiography are the key to the diagnosis.
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Surgical resection is still the standard and definitive treatment. and with minimal complications.
1
Introduction
Cor triatriatum dexter (CTD) represents a rare congenital cardiac anomaly characterized by the persistence of the right venous valve, resulting in the partitioning of the right atrium into two distinct chambers. The proximal chamber receives venous return from the superior vena cava, inferior vena cava, and coronary sinus, while the second chamber communicates with the right atrial appendage (RAA) and tricuspid valve. This malformation frequently coexists with other right-sided cardiac defects, including atrial septal defect (ASD), Ebstein anomaly, right ventricular hypoplasia, and pulmonary stenosis [ ].
In the presence of atrial communication, CTD may function as a valve-like structure that facilitates right-to-left shunting, thereby inducing central cyanosis. Definitive management typically involves surgical resection of the dividing membrane, which is particularly indicated in cases presenting with obstructive physiology or clinically significant cyanosis [ ].
2
Case presentation
A 7-year-old Caucasian Egyptian male child presented with fatigue and exertional dyspnea. There was no relevant past medical history and no family history of similar conditions.
On general examination, the patient was cyanosed with an oxygen saturation fluctuating from 80 to 85 %, blood pressure 90/50 mmHg, and a wide pulse pressure was recorded. Cardiac examination showed audible ejection systolic murmur over the pulmonary area. The chest and abdominal examinations were irrelevant.
Laboratory investigations showed Hemoglobin 17 g/dl with elevated hematocrit denoting chronic hypoxemia. Electrocardiography was normal, and chest X-ray showed non-significant findings.
Transthoracic echocardiography (TTE) showed Large ASD secundum , a prominent ridge dividing the RA into two parts (prominent Eustachian valve versus a membrane), and moderate valvular pulmonary stenosis (peak systolic gradient 43 mmHg), with no evident cause of the present desaturation. Good RV longitudinal systolic function was recorded (TAPSI 18 mm). ( Fig. 1 ).
Transesophageal echocardiography (TEE) was done and showed high secundum ASD measuring 12.8 mm with a bidirectional flow across ( Fig. 2 , video 1 ) . A non-obstructive membrane on the right side (cor triatrium dexter) was detected, dividing the right atrium into 2 parts, one receiving venous blood from SVC and IVC and the second chamber related to RAA and tricuspid valve ( Fig. 3 , video 2, 3 ). CTD redirecting blood through ASD from right to left side, which explained the present central cyanosis. Moderate valvular pulmonary stenosis is also confirmed by TEE.
The patient was referred to the cardiac surgery department. The surgery was conducted on cardiopulmonary bypass with aortic-bicaval cannulation. Right angled venous cannula was used for selective IVC cannulation to give more space to deal with the prominent eustachian valve (if present).
