Juxtaposition of the atrial appendages: a clinical series of 22 patients

Left Juxtaposition of the Right Atrial Appendage: Pitfalls in Diagnosis

Several congenital anomalies of the right atrial appendage (RAA) have been described including aneurysm, herniation (in association with a pericardial defect), and left juxtaposition. The left juxtaposition of the RAA (LJRAA), first described by Birmingham in 1893 and subsequently introduced by Dixon in 1954, is usually associated with complex cardiac malformations such as obstruction of the left ventricular outflow tract. In this case report, we will describe an unusual variant of LJRAA in the absence of any other cardiac defects, which was initially misinterpreted as an aortic dissection. The correct diagnosis was made after careful reinterpretation and the use of multiple imaging modalities as highlighted.

Juxtaposition of the Atrial Appendages: A Large Echocardiographic Series

Juxtaposition of the atrial appendages is known to occur in specific congenital heart lesions. Recognition of these variants is critical in balloon atrial septostomy and atrial switch operations. There remains little clinical data on the prevalence and associations of these lesions. This is the largest echocardiographic study of juxtaposition of the atrial appendages. This is a retrospective study using the Mt. Sinai echocardiogram database (EchoLAN), which contains echocardiogram reports performed or reviewed at Mt. Sinai Hospital (New York, NY) between 1992 and 2019. Each report was reviewed for associated intracardiac and extracardiac anomalies and the prevalence of juxtaposed atrial appendage among specific diagnosis, including tricuspid atresia, transposition of the great arteries, and double outlet right ventricle, was calculated. Descriptive and analytical statistics were performed as applicable, including Fisher's exact test, with p value < 0.05 considered statistically significant. Forty-nine patients had juxtaposed atrial appendages (1.2/1000 patients): Thirty-eight had LJRAA (0.9 per 1000 patients) and eleven had RJLAA (0.3 per 1000 patients). LJRAA was seen in 22% of tricuspid atresia, 6% of d-TGA, 1% of l-TGA, and 5% of DORV. RJLAA was seen in 2% of DORV, and none of the other lesions. Of associated lesions, dextrocardia, mesocardia, transposition, tricuspid atresia, double inlet left ventricle, and pulmonary valve stenosis were more likely to be present in LJRAA, while bicuspid aortic valve and left ventricular hypoplasia were more likely to be present in RJLAA. This study reaffirms our understanding of juxtaposition of the atrial appendages, its prevalence, and clinical importance.

Juxtaposition of atrial appendages: Evaluation of cardiovascular morphology and associated anomalies on multidetector computed tomography angiography

AIM

To evaluate the morphology and associated cardiovascular abnormalities in patients with juxtaposition of atrial appendages (JAA) on multidetector computed tomography (MDCT) angiography.

MATERIALS AND METHODS

We performed the retrospective study at a tertiary referral center to identify patients diagnosed with JAA on MDCT angiography using dual-source CT scanner between January 2014 and April 2021. The various imaging abnormalities evaluated included the type of JAA, morphological and positional classification of JAA, atrial situs, cardiac position, atrioventricular and ventriculoarterial connections, great vessel relationship, and other associated cardiovascular anomalies.

RESULTS

We identified 129 patients with JAA. Left-sided juxtaposition was seen in 124 (96.1%) patients while right-sided juxtaposition was seen in 5 (3.9%) patients. Among patients with left-sided juxtaposition, frequent cardiovascular associations included outflow tract malformations (100%), hypoplastic right ventricle (40.3%), tricuspid atresia (32.2%), and right-sided heart (19.4%). The most frequent outflow tract malformation was double outlet right ventricle (DORV; 60.5%) followed by transposition of great arteries (20.1%) and transposed aorta with pulmonary atresia (18.5%). In patients with right-sided juxtaposition, outflow tract malformation was seen in three (60%) patients with one (20%) patient each showing DORV, transposed aorta with pulmonary atresia, and tetralogy of Fallot, respectively.

CONCLUSION

The identification of JAA on MDCT angiography suggests coexistence of various complex congenital heart diseases, especially outflow tract malformations. A meticulous search is imperative to identify this anomaly before interventional or surgical procedures to avoid complications.

Late detection of communication between juxtaposed atrial appendages

A 40-year-old woman underwent an atrial septal defect closure 4 years before presentation. During the operation, juxtaposition of the atrial appendages was found simultaneously but no obvious communication was found between the appendages. She recently experienced desaturation on exercise, and the residual communication was found between the juxtaposed atrial appendages. The residual communication was closed from the right to the left atrium. Herein, we report the rare case of juxtaposition of the atrial appendages with residual communication between them after an atrial septal defect closure.

Juxtaposition of the atrial appendages: A nidus for thrombus in atriopulmonary Fontan?

Juxtaposition of atrial appendages is a rare cardiac congenital anomaly, usually associated with other cardiac malformations. Until now, it has not been linked to any significant clinical implications. We report cardiovascular magnetic resonance (CMR) findings of two adult patients who underwent atriopulmonary Fontan operation in the setting of left juxtaposition of the atrial appendages. The patients were in sinus rhythm at the time of the CMR study. Both patients had episodes of sustained atrial tachyarrhythmia requiring electrical cardioversion and were anticoagulated with warfarin with target INR 2-3. CMR images showed a thrombus located in the enlarged and juxtaposed right appendage in both patients. Blood flow frequently appears slow or sluggish in the dilated right atrium following atriopulmonary Fontan surgery. In addition, cine CMR suggested that blood flow reaches very low velocities in the massively dilated juxtaposed right atrial appendage cul-de-sac, thus potentially creating a substrate for clot formation. These findings propose that juxtaposed atrial appendages in atriopulmonary Fontan is an additional risk factor for clot formation, specifically in the dilated right atrial appendage on the left side juxtaposed with the left atrial appendage and that prophylactic anticoagulation is highly justified in these patients.

Juxtaposed atrial appendages: A curiosity with some clinical relevance

If the atrial appendages lie adjacent to each other on same side of the great arteries, instead of encircling their roots, they are referred as juxtaposed. Right juxtaposition of atrial appendages is less common than left juxtaposition. The images demonstrate the classical radiological, echocardiographic, and surgical images of juxtaposed atrial appendages. Their clinical incidence, associations, and relevance during interventional and surgical procedures are discussed.

Left atrial appendage occlusion for stroke prevention

Atrial fibrillation (AF) remains the most common arrhythmia encountered in clinical practice. One of its more common deleterious effects is the development of thromboembolism leading to stroke. The left atrial appendage (LAA) has been shown to the site of the majority of thrombus formation leading to stroke. Anticoagulation with warfarin has been the treatment of choice for prevention of embolic events. Newer anticoagulants have been developed but they still have the potential side effect of causing major bleeding. Occlusion of the LAA has emerged as an alternative therapeutic approach to medical therapy. The aim of this article is to discuss in detail the role of the LAA in thromboembolism in AF, role of device and surgical therapies, and the current clinical data supporting their use. This is particularly timely in that there is now an approved LAA closure device approved in the US for stroke prevention in patients with nonvalvular AF.

Anatomically corrected malposition of the great arteries {S, D, L} with left juxtaposition of the atrial appendages in DORV: influence on surgical approach

The case of an infant with double outlet right ventricle with anatomically corrected malposition of the great arteries, bilateral infundibulum, and an echocardiographically routable ventricular septal defect (VSD) is presented. After numerous efforts to visualize the margins of the VSD, the best surgical exposure of the VSD was through the aorta. We believe this to be the first report of this phenomenon, which results from the left-sided position of the aorta and the presence of left juxtaposition of the atrial appendages.

Atrial septal defect repair by inversion of a juxtaposed left atrial appendage

A 7-year-old child was noted to have dextrojuxtaposition of the left atrial appendage at the time of surgical atrial septal defect repair. Given the favourable anatomic location and size of the atrial appendage, it was inverted and used to close the atrial defect. This is the first report of atrial septal defect repair using a juxtaposed atrial appendage. The cardiac anatomy and theoretical benefits of this repair are discussed.

Is the left atrial appendage more than a simple appendage?

The left atrial appendage (LAA) is a cardiac structure with unique anatomic and functional features. It is significantly more than a simple chamber appended to the left atrium (LA), differing from the LA in structure, function, and hormonal activity. Unfortunately, it is the source of more than 90% of cardiac-based emboli, particularly in atrial fibrillation, mandating lifelong anticoagulation. Percutaneous LAA exclusion was developed to limit or eliminate cardioembolic events in patients with atrial fibrillation. Benign healing of the appendage occurs without adverse hemodynamic effects, and with no residual surface thrombus or tissue damage. The feasibility of this treatment is now established, suggesting that percutaneous therapy is safe, practical and possibly effective to eliminate the need for anticoagulation and significantly reduce cardioembolic events.

Malalignment of the septum primum with abnormally positioned left atrial appendage: unusual combination in a Shone's heart

This case discusses a Shone's variant with small left ventricle and mitral valve, bicuspid aortic valve, coarctation of the aorta, an unusual arrangement of atrial appendages, and partially anomalous pulmonary venous drainage due to a deviated atrial septum. The left atrial appendage could be directly entered from the right atrium at catheterization, but it was positioned behind the great arteries. The right atrial appendage was normal in origin and orientation. The implications of this anatomy in fetal cardiac development are reviewed.

A model for left juxtaposition of the atrial appendages in the chick

The morphogenesis of most types of human congenital cardiac malformations is still obscure. The reasons for this are, first, the paucity of data from human embryos and fetuses and, second, the paucity of appropriate animal models. During the past few years, we have tested several chemicals for their teratogenic potential, hoping to find, particularly in the chick, substances that could be used for the development of models for specific cardiac malformations. We have now discovered that suramin, an antitrypanosomal drug, can induce a special type of congenital cardiac defect in which the two atrial appendages are positioned to the left of the great arteries. This situation resembles the situation found in humans and classified as left juxtaposition of the atrial appendages. In the present study, we have analysed the pathomorphological features of a series of our chicken hearts to assess precisely how accurately these cardiac malformations in the chick correspond to the situation seen in the human. We found that the cases observed in the chick did, indeed, have many features in common with the human cases described in the literature. This suggests that we have developed an animal model for human left juxtaposition. Our model could be used for two kinds of embryological studies: first, documentation of the morphogenesis of left juxtaposition; and second, studies on the mechanisms driving the normal positional changes between the atriums and outflow tract of the embryonic heart during the late phase of cardiac looping. The fact that left juxtaposition of the atrial appendages can be induced by suramin might help to elucidate the molecular mechanisms underlying this type of congenital cardiac malformation. Furthermore, the fact that suramin is used for the chemotherapy of frequent tropical diseases, such as African trypanosomiasis and onchocerciasis, poses the question as to whether this drug might play a role in the aetiology of left juxtaposition in some human populations.