Case 56: Cor Triatriatum Dexter

Abstract

A 70-year-old Afghan refugee who recently immigrated to the United States had a history of dyspnea on exertion for several months. Medical history included systemic hypertension, recent onset of congestive heart failure, and recent peripheral pitting edema of the lower extremities. A soft systolic heart murmur with a split S 2 was present at physical examination. An echocardiogram showed findings that prompted the request for a cardiac magnetic resonance (MR) imaging examination for further evaluation (Figs 1-3). IMAGING FINDINGSMR images demonstrated moderate right atrial enlargement, with a membrane separating the right atrium into an anterior and a posterior chamber (Figs 1, 2). Turbulent flow was seen across this membrane (Fig 2; Movie, radiology.rsnajnls.org/cgi /content/full/10.1148/radiol.2263001845/DC1) and indicated that it was extensively fenestrated and not completely obstructive. Gradient-echo cine images demonstrated a small secundum atrial septal defect (ASD) that was approximately 4 mm in diameter (Fig 3). A small left-to-right jet through the ASD was also seen on the cine images. The right ventricle was mildly enlarged. There was mild enlargement of bilateral pulmonary arteries. Mild left ventricular hypertrophy was present, which was likely related to the patient's known systemic hypertension. Findings of the examination of the remainder of the heart were within normal limits. DISCUSSIONWhile on the basis of the clinical findings the differential diagnosis considerations included entities such as constrictive pericarditis, tricuspid stenosis, or right atrial tumor, the imaging findings helped to narrow the possibilities to one diagnosis: cor triatriatum dexter. The term cor triatriatum, also known as "triatrial heart," usually refers to cor triatriatum sinister or "divided left atrium," which is a rare condition with estimated incidence of 0.1% of all congenital cardiac malformations (1). In cor triatriatum sinister, the left atrium is divided by a membrane into a posterior-superior chamber that receives the four pulmonary veins and an anterior-inferior chamber that connects to the left ventricle by means of the mitral valve. Although several theories have been proposed in the literature regarding the development of cor triatriatum sinister, the most widely accepted theory is that this anomaly results from a failure of incorporation of the common pulmonary vein into the left atrium (2,3).The case presented in this article is an example of cor triatriatum dexter in which a membrane divides the right atrium into two chambers. It is generally believed that cor triatriatum dexter results from persistence of the right valve of the sinus venosus (4 -6). 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 sinoatri...

Cor triatriatum dexter in two adult patients

“…Several modalities have been used and compared for the diagnosis of cor triatriatum dexter in the literature, including angiography, echocardiography and magnetic resonance imaging (MRI). Reports about the use of echocardiography mainly date from the mid-1980 to early 1990 [3,4]. Roldan et al [3] stated that 3-dimensional echocardiography was an excellent method for teaching the pathologic anatomy in these patients.…”

Echocardiographic Finding of Non-Obstructive Fibromuscular Band in Right Atrium

“…It leads to questions for further research, whether to call it Cortriatrium dexter or not? IT was an important and rare disease which was diagnosed accidentally [31][32][33][34][35][36][37][38][39][40][41].…”

Anesthetic management of non-cardiac surgery with adult onset type of cor triatriatum sinister -A case report-

“…Many theories for cor triatriatum sinister have been suggested; however, the most widely accepted theory is that it results from a failure of incorporation of the common pulmonary vein into the left atrium during fetal life [4]. This abnormality involves subdivision of the LA by an oblique fibromuscular membrane that creates a proximal chamber receiving the pulmonary veins (accessory LA) and a distal chamber that includes the left atrial appendage and mitral valve (true LA) [5].…”

“…Cardiac CT and MRI provide better spatial resolution and superior tissue contrast compared with echocardiography. Moreover, cardiac CT and MRI can be performed easily in multiple planes [4]. Intra-operative TEE was not used in this case because the pre-operative cardiac evaluation showed only mild MS physiology with a large membrane fenestration, mild MR, and mild pulmonary hypertension, which was in the near-normal range.…”