A 65-day-old girl presented to the emergency room with lethargy, requiring emergency venoarterial extracorporeal membrane oxygenation for refractory cardiogenic shock. Initially, hypoplastic left heart syndrome was suspected. However, cor triatriatum with a pinpoint opening on the membrane was diagnosed based on a detailed echocardiographic examination. After membrane resection, the left heart size was restored. However, follow-up echocardiography performed 4 months later showed occlusion of both upper pulmonary veins and stenosis in both lower pulmonary veins. Hybrid balloon angioplasty was performed in all pulmonary veins, and stents were inserted into the right upper and lower pulmonary veins. Despite repeated balloon angioplasty, all pulmonary vein stenosis progressed over 6 months and the patient expired while waiting for a heart-lung transplant. Even after successful repair of cor triatriatum, short-term close follow-up is required for detecting the development of pulmonary vein stenosis.

Cor triatriatum sinister is a very rare cardiac anomaly that may lead to pulmonary hypertension, right ventricular dilation, and eventually right heart failure. We report a case of a toddler who presented with respiratory distress and cardiomegaly and was found to have cor triatriatum sinister with a restrictive communication, decompressing vertical vein, pulmonary hypertension, severe tricuspid regurgitation, and severe right ventricular dysfunction. She underwent a successful surgical repair, with normalisation of right ventricular function and pulmonary artery pressure.

A 14-year-old boy presented to us with a diagnosis of severe asthma and oxygen desaturation of 76% on a 6-minute-walk test. A contrast echocardiogram revealed echocontrast in the left and right atria simultaneously. A secundum atrial septal defect and partial cor triatriatum dexter were diagnosed, and the atrial defect was closed by cardiac catheterisation.

Introduction: The term cor triatriatum is used to describe a fibromuscular partition that divides an atrium into two compartments. It was first used by Borst in 1905, although the lesion had been described before by Church in 1868. Both described divided left atrial chamber (also referred to as cor triatriatum sinister). The incidence of the divided left atrial chamber among patients with congenital heart disease is reported at 0.1% and 0.4% in an autopsy study. Divided right atrial chamber – also referred to as cor triatriatum dexter – is even rarer to an extent that there is no reported incidence and only few hundred cases have been reported so far. A search through pubMed library revealed only 90 publications on humans, either under the term “dexter” or “dextrum”. We would like to report a new association of bilateral divided atrial chambers and pulmonary vein stenosis, with a review of the literature.

Cor triatriatum dexter is an extremely rare congenital anomaly of the right atrium. It occurs because of the persistence of the right sinus venosus valve, resulting in partitioning of the right atrium. Most of the described cases of cor triatriatum dexter in the literature were incidental findings on echocardiogram or at necropsy.

We present a case report of a 7-year-old girl who was referred to us for further assessment, with a possible diagnosis of coarctation of the aorta. Initial investigations confirmed not only the presence of a long segment coarctation of the aorta, but also a large obstructive membrane in the right atrium.

A catheter intervention was performed to stent the coarctation segment, and the fibro-muscular shelf in the right atrium was surgically resected.

Cor triatriatum sinister is an uncommon congenital cardiac anomaly accounting for 0.1% of all congenital cardiac malformations, with an anomalous venous return being a frequently associated condition. We present the case of a 14-year-old girl misdiagnosed as having an atrial septal defect with pulmonary hypertension who actually had a cor triatriatum with a left upper anomalous pulmonary venous return to the innominate vein.

We report the case of a child with cor triatriatum dexter masquerading as Ebstein's anomaly on transthoracic echocardiography. This was attributed to a floppy membrane arising from the right atrium, protruding into the tricuspid valve and pushing the leaflets downwards, giving an impression of Ebstein's anomaly. The importance of recognising this pitfall will prevent misdiagnosis of Ebstein's anomaly.

Reported is a case with a rare association of divided left atrium, supramitral stenosing ring of the left atrium, connection of the left superior caval vein to the roof of the left atrium, unroofed coronary sinus with an interatrial communication at the mouth of the unroofed sinus and ventricular septal defect. The need for a complete echocardiographic examination in the presence of pulmonary venous obstruction is emphasized. Surgery was successful in spite of significant preoperative pulmonary hypertension.

Division of the morphologically left atrium is a rare abnormality, constituting around 0.1% of congenital heart disease. It may coexist with other cardiac abnormalities, and this association may obscure its recognition. We report an uncommon association with tricuspid atresia and discordant ventriculo-arterial connections, the latter dominating the clinical picture. Accurate diagnosis was made by transthoracic cross-sectional echocardiography, and the patient was referred to surgery without need for cardiac catheterisation.

Division of the left atrium is a rare congenital lesion, but one which is amenable to complete surgical correction. We describe twin brothers, demonstrated to be monozygotic, who presented in infancy with cardiac failure, pulmonary congestion and mild cyanosis. Both were found to have systemic and pulmonary venous return to a common atrial chamber, separated from the left atrial appendage and the vestibule supporting the mitral valve by a typical muscular diaphragm with a single small orifice. In one twin, there was also persistence of the left superior caval vein, while, in the other twin, a remnant of the primary atrial septum was present. Excision of the diaphragm and neoseptation of the atrial chambers was performed in both infants. At 10 years after surgery, there was normal growth and development in both twins, with no evidence of recurrent obstruction.

Congenital division of an atrial chamber is a very rare congenital malformation that more commonly affects the left atrium but which may, in rare circumstances, involve the right atrium. Such a divided right atrium may present with symptoms consistent with increased portal venous pressure. Reported is a case with unusual clinical presentation. The patient underwent resection of the dividing shelf with good postoperative results.

In a young infant with divided left atrium, unroofed coronary sinus syndrome, and persistent left superior caval vein, the pulmonary venous blood was successfully routed, after atrial septectomy, to the mitral valve by constructing a baffle using the partially detached diaphragm which had initially separated the pulmonary venous and vestibular components of the left atrium. The baffle was augmented with a patch of untreated autologous pericardium.

We describe the unusual association of a divided left atrium (cor triatriatum) with an atrioventricular septal defect with separate atrioventricular orifices in an eight-year-old asymptomatic girl. The diagnosis had been made by cross-sectional echocardiography combined with Doppler technology and color-flow mapping. These methods together demonstrate both the anatomic and hemodynamic findings.

Objective: Using a newly acquired archive of previously prepared material, we sought to re-examine the origin of the pulmonary vein in the human heart, aiming to determine whether it originates from the systemic venous sinus (“sinus venosus”), or appears as a new structure draining to the left atrium. In addition, we examined the temporal sequence of incorporation of the initially solitary pulmonary vein to the stage at which four venous orifices opened to the left atrium. Methods: We studied 26 normal human embryos, ranging from 3.8 mm to 112 mm crown-rump length, and representing the period from the 12th Carnegie stage to 15 weeks of gestation. Results: The pulmonary vein canalised as a solitary vessel within the mediastinal tissues so as to connect the intraparenchymal pulmonary venous networks to the heart, using the regressing dorsal mesocardium as its portal of cardiac entry. The vein was always distinct from the tributaries of the embryonic systemic venous sinus. The orifice of the solitary vein became committed to the left atrium by growth of the vestibular spine. During development, a marked disparity was seen between the temporal and morphological patterns of incorporation of the left-sided and right-sided veins into the left atrium. The pattern of the primary bifurcation was asymmetrical, a much longer tributary being formed on the left than on the right. Contact between the atrial wall and the venous tributary on the left initially produced a shelf, which became effaced with incorporation of the two left-sided veins into the atrium. Conclusions: The initial process of formation of the human pulmonary vein is very similar to that seen in animal models. The walls of the initially solitary vein in humans become incorporated by a morphologically asymmetric process so that four pulmonary veins eventually drain independently into the left atrium. Failure of incorporation on the left side may provide the substrate for congenital division of the left atrium.

We present the eighth published case of divided left atrium co-existing with tetralogy of Fallot. This is the first report of preoperative echocardiographic diagnosis of this unusual combination of defects. Demonstration of a partition within the left atrium is imperative for successful repair of the combined lesions. We draw attention to the need for careful echocardiography in patients where an obstruction to pulmonary venous drainage would dramatically affect the outcome subsequent to surgical correction.

We describe an infant with hypoplasia of the left heart diagnosed prenatally who, at birth, had signs of severe pulmonary venous obstruction. Echocardiography indicated normally connecting pulmonary veins, and showed a paradoxical right-to-left shunt across a patent oval foramen. Postmortem examination revealed that the obstruction was due to a divided left atrium, or cor triatriatum sinister, with an imperforate muscular diaphragm separating completely the two components of the divided atrium.