Double Outlet Right Atrium Associated with Large Atrial and Ventricular Septal Defects in a Neonate with Down Syndrome: A Case Illustrated by Imaging and Surgical Findings

Double Outlet Right Atrium Associated with Large Atrial and Ventricular Septal Defects in a Neonate with Down Syndrome: A Case Illustrated by Imaging and Surgical Findings | Research Square window.SnipcartSettings = { analytics: { enabled: false } }; (function() { var accessVector = localStorage.getItem('access_vector') || ''; window.dataLayer = window.dataLayer || []; if (accessVector) { window.dataLayer.push({ user: { profile: { profileInfo: { snid: accessVector } } } }); } })(); (function(w,d,s,l,i){w[l]=w[l]||[];w[l].push({'gtm.start':new Date().getTime(),event:'gtm.js'});var f=d.getElementsByTagName(s)[0],j=d.createElement(s),dl=l!='dataLayer'?'&l='+l:'';j.async=true;j.src='https://www.googletagmanager.com/gtm.js?id='+i+dl;f.parentNode.insertBefore(j,f);})(window,document,'script','dataLayer','GTM-K279D39R'); Browse Preprints In Review Journals COVID-19 Preprints AJE Video Bytes Research Tools Research Promotion AJE Professional Editing AJE Rubriq About Preprint Platform In Review Editorial Policies Our Team Advisory Board Help Center Sign In Submit a Preprint Cite Share Download PDF Case Report Double Outlet Right Atrium Associated with Large Atrial and Ventricular Septal Defects in a Neonate with Down Syndrome: A Case Illustrated by Imaging and Surgical Findings Mustafa Nalbant, Fatma Sevinç Şengül, Okan Yıldız, Alper Güzeltaş This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-9520548/v1 This work is licensed under a CC BY 4.0 License Status: Posted Version 1 posted You are reading this latest preprint version Abstract Double outlet right atrium (DORA) is an exceptionally rare congenital cardiac anomaly characterized by direct right atrial inflow into both ventricles, often resulting in significant hemodynamic compromise. We report a case of DORA in a neonate with Down syndrome and large coexisting ASD and VSD, who underwent successful surgical repair at 7 months of age. This case, supported by echocardiographic and intraoperative documentation, highlights the clinical presentation, diagnostic challenges, and surgical findings of this rare anomaly. Figures Figure 1 Introduction Double outlet right atrium (DORA) is an extremely rare congenital cardiac malformation, characterized by anomalous atrioventricular septation resulting in both ventricles receiving direct inflow from the right atrium. This unusual anomaly is associated with significant hemodynamic disturbances and typically presents in the neonatal period with cardiopulmonary symptoms. DORA may coexist with a wide spectrum of congenital heart defects including atrial septal defect (ASD), ventricular septal defect (VSD), atrioventricular septal defect (AVSD), double outlet right ventricle (DORV), and transposition of the great arteries (TGA). Genetic syndromes such as trisomy 21, heterotaxy syndromes, and 22q11 deletion are commonly associated with this anomaly ( 1 – 3 ). We present a rare case of DORA accompanied by a large perimembranous VSD (extending from the inlet to the outlet) and secundum ASD in a neonate with confirmed Down syndrome. To our knowledge, the Transthoracic echocardiographic (TTE) and intraoperative documentation in this case contributes valuable visual insights to the limited existing literature on this anomaly. Case presentation A female neonate was born at 37 + 3 weeks of gestation with a birth weight of 3380 grams via spontaneous vaginal delivery. On postnatal day 3, she developed respiratory distress and was admitted to the neonatal intensive care unit. Phenotypic features were consistent with Down syndrome, and karyotyping confirmed a diagnosis of trisomy 21 (47, XX + 21). Initial TTE examination revealed a large secundum-type ASD and a large perimembranous VSD (extending from the inlet to the outlet). The patient was referred to our pediatric cardiology department for further evaluation after stabilization and discharge. At 1 month of age, she was referred to our clinic, weighing 3600 grams, indicating a weight gain of only 220 grams in the first month of life. Clinical examination revealed a respiratory rate of 52 breaths per minute, a systolic murmur graded 4–5/6, and oxygen saturation of %97 on room air. Electrocardiography showed sinus tachycardia (145 bpm) with right axis deviation. Chest X-ray demonstrated cardiomegaly with a cardiothoracic index of 55–60% and increased pulmonary vascular markings. TTE confirmed a large (8mm) secundum-type ASD, a wide perimembranous VSD (with a color Doppler jet width of up to 6 mm and multiple flow streams), and a unique anomaly: both the right and left ventricles received direct inflow from the right atrium, consistent with DORA (Fig. 1 A, Video 1). The interatrial septum appeared malposed to the left. The patient was started on oral anti-congestive medications and high-calorie nutritional supplementation, with monthly follow-up planned at the pediatric cardiology outpatient clinic. During follow-up, enlargement of the left heart chambers and increased pulmonary blood flow were noted. In order to prevent the progression to irreversible pulmonary vascular resistance and the risk of heart failure secondary to chronic volume overload, surgical correction was scheduled at 7 months of age, when the patient weighed approximately 9 kilograms. Intraoperative examination revealed leftward deviation of the interatrial septum and a crossing chord emerging from the left ventricle and attaching to the tip of the right AV valve apparatus. The right AV valve anteroseptal commissure was detached from the annulus to leave the left-sided chord in place, and the detached segment of the tricuspid valve was resutured to the annulus. The tricuspid valve leaflets were approximated at the midline, and cleft-like structures were closed individually, resulting in mild residual regurgitation. Following a transverse incision of the interatrial septum, the left AV valve was evaluated and showed no evidence of stenosis or insufficiency. Assessment of the outlet VSD demonstrated approximately 50% anteroseptal malalignment, which was repaired using a pericardial patch. (Fig. 1 B, Video 2). These findings confirmed the preoperative diagnosis of DORA. The patient was extubated after 48 hours and transferred to the pediatric ward on postoperative day 4. She was discharged home in stable condition after 4 days of uneventful inpatient follow-up. At her outpatient follow-up, she remained clinically stable with only mild residual regurgitation in both AV valves and required no medical therapy. Discussion Double outlet right atrium is an extremely rare congenital anomaly characterized by anomalous drainage of the right atrium into both ventricles due to atrioventricular septal maldevelopment. ( 1 , 2 ). Previous studies have emphasized the risk of misdiagnosis as atrioventricular septal defect, particularly in patients with trisomy 21 ( 2 ). Therefore, recognition of DORA as a distinct anatomical entity is essential to ensure accurate diagnosis and to guide surgical strategy. TTE generally provides sufficient diagnostic information, but advanced modalities such as cardiac magnetic resonance imaging or computed tomography may be required in patients with complex anatomy ( 1 , 4 ). While TTE remains the cornerstone of diagnosis, detailed assessment of atrial inflow and septal alignment is critical to distinguish DORA from other atrioventricular septal malformations. Transthoracic and transesophageal echocardiography, complemented by three-dimensional imaging, are critical in delineating atrial septal malalignment and the atrioventricular valve attachments. Advanced imaging modalities such as cardiac CT or MRI can further aid in defining atrial inflow pathways and excluding AVSD, in which a common atrioventricular junction and bridging leaflets are typically present. In our case, TTE clearly demonstrated the anomalous atrial inflow and septal malalignment, which was crucial for preoperative planning. In our patient, a predominant left-to-right shunt pattern was present due to the coexistence of DORA with a large secundum atrial septal defect and a perimembranous ventricular septal defect. Although the right atrium was observed to open into both ventricles because of DORA, it predominantly drained into the right ventricle. Therefore, the amount of deoxygenated blood passing from the right atrium to the left ventricle was limited, and no significant clinical cyanosis was observed. Similar findings have been described in previous case reports ( 3 ). Surgical management depends on the specific anatomical configuration, with reported techniques including closure of abnormal atrioventricular orifices, reconstruction of the interatrial septum, and repair of associated lesions ( 1 , 4 ). In our patient, surgical repair consisting of closure of the septal defects and anatomical realignment of the atrial septum was successfully performed, resulting in favorable postoperative outcome. DORA represents a unique entity within the spectrum of atrioventricular connection anomalies. Our case, presenting with DORA in association with a large secundum atrial septal defect and a perimembranous ventricular septal defect, illustrates the potential for significant hemodynamic compromise in the neonatal period. The term “hemodynamic compromise” in DORA refers to the potential for early postnatal circulatory instability due to atrioventricular malalignment, which may lead to unbalanced inflow, atrioventricular valve regurgitation, or decreased pulmonary blood flow. In our patient, large interatrial and interventricular communications maintained balanced filling and effective mixing, preventing neonatal decompensation. The literature underscores its frequent misdiagnosis as atrioventricular septal defect, particularly in syndromic infants, and emphasizes the heterogeneity of clinical presentation ( 1 – 5 ). The diagnosis of DORA is not determined solely by the degree of tricuspid valve override but by the malalignment of the interatrial septum and the drainage pattern of the right atrium into both ventricles. In our patient, echocardiographic findings demonstrated that the right atrium drained directly into both ventricles, predominantly into the right ventricle and only partially into the left ventricle through a smaller orifice. This pattern was caused by leftward deviation of the interatrial septum, rather than true tricuspid override. Although both tricuspid overriding and DORA demonstrate flow from the right atrium into both ventricles, they possess distinct anatomic characteristics. Both entities primarily result from malalignment of the atrial and ventricular septa; however, in DORA, two separate atrioventricular valve orifices are identified, corresponding to distinct right and left AV connections. In contrast, tricuspid overriding represents a single right atrioventricular connection with the tricuspid valve overriding the ventricular septum. These distinctions have been summarized in previous comparative studies ( 6 ). These findings were consistent across echocardiographic and intraoperative evaluations, confirming double outlet right atrium (DORA) anatomy. Conclusion Early recognition and individualized surgical correction, including septal closure and anatomical realignment, are essential for achieving optimal outcomes. Our case contributes to the limited evidence based on this rare condition and highlights the importance of heightened awareness among pediatric cardiologists and congenital heart surgeons. Declarations Written informed consent for publication of this case report and any accompanying images was obtained from the patient’s parents. Data Sharing Statement The data that support the findings of this study are available from the corresponding author upon reasonable request. Conflict of Interest: The authors declared no conflicts of interest with respect to the authorship and/or publication of this article. Funding: The authors received no financial support for the research and/or authorship of this article. Author Contribution Author Contributions: Designed the article: M.N.; Collected the data: M.N, F.S.S.; Reviewed literature: M.N, O.Y; Writed the article: F.S.S., M.N; Made critical review: A.G. References - Ambra M, Nuri HA, Pome G, Marasini M, Francesco S (2020) Double-outlet right atrium: review of a rare anomaly with an exemplary case. World J Pediatr Congenit Heart Surg 11(1):79–84 - Sivakumar K, Mohanty S, Varghese R (2021) Double-outlet right atrium – a rare and easily misdiagnosed entity. J Indian Acad Echocardiogr Cardiovasc Imaging 5:233–235 - Tanıdır IC, Çınar B, Güzeltaş A (2021) Double-outlet right atrium in an asymptomatic 8-year-old girl. Turk Kardiyol Dern Ars 49(1):86–88 - Thomas E, Zacharias S, Kandachar PS, Al-Maskary S (2020) Double outlet right atrium—A bridge across the bridging leaflets. J Card Surg 35(12):3596–3600 - Borghol W, Alfaksh F, Karaja S, Barakat L, Takkem S (2025) An isolated double-inlet right ventricular malformation: a case report and review of the literature. J Med Case Rep . ;19(1):229. Published 2025 May 17. 10.1186/s13256-025-05300-4 - Edwin F, Kinsley RH, Mamorare HM, Govendrageloo K (2012) The spectrum of double-outlet right atrium including hearts with three atrioventricular valves. Eur J Cardiothorac Surg 41(4):947–949. 10.1093/ejcts/ezr073 Additional Declarations No competing interests reported. Supplementary Files DORAechoVideo1.mp4 DORAoperationVideo2.mp4 Cite Share Download PDF Status: Posted Version 1 posted You are reading this latest preprint version Research Square lets you share your work early, gain feedback from the community, and start making changes to your manuscript prior to peer review in a journal. As a division of Research Square Company, we’re committed to making research communication faster, fairer, and more useful. We do this by developing innovative software and high quality services for the global research community. Our growing team is made up of researchers and industry professionals working together to solve the most critical problems facing scientific publishing. Also discoverable on Platform About Our Team In Review Editorial Policies Advisory Board Help Center Resources Author Services Accessibility API Access RSS feed Manage Cookie Preferences © Research Square 2026 | ISSN 2693-5015 (online) Privacy Policy Terms of Service Do Not Sell My Personal Information {"props":{"pageProps":{"initialData":{"identity":"rs-9520548","acceptedTermsAndConditions":true,"allowDirectSubmit":true,"archivedVersions":[],"articleType":"Case Report","associatedPublications":[],"authors":[{"id":634341476,"identity":"fe95419c-c845-40df-884d-8336d1c320e1","order_by":0,"name":"Mustafa Nalbant","email":"data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAZAAAAAyAQMAAABI0h/eAAAABlBMVEX///8AAABVwtN+AAAACXBIWXMAAA7EAAAOxAGVKw4bAAAA8UlEQVRIiWNgGAWjYFAC5jYQaWd/vP3gAyCDh4+wFkaQFoNkhjNnkg1AWtiI1cLYcCPBTALEJ6jFnP1g24OfO/4wM85ISKv8mmMnw8bA/PDRDTxaLHsS2w17zxjwMfM8PHZbdlsy0GFsxsY5eLQYHEhsk+BtM2BmY09Iuy25jRmohYdNGq+W8w/bJP+2GTD2MCSYFUtuqydCy43ENmmgLYwzOBLMGD9uO0yMloftxrJtxskGPGeSpRm3HedhYybkl/PJxx6+bZOzM2BvP/jx57Zqe3725oeP8WlBAcw8YJJY5SDA+IMU1aNgFIyCUTBiAADVuEeqFUkbRwAAAABJRU5ErkJggg==","orcid":"","institution":"Sağlık Bilimleri Üniversitesi","correspondingAuthor":true,"prefix":"","firstName":"Mustafa","middleName":"","lastName":"Nalbant","suffix":""},{"id":634341480,"identity":"1167b46c-4635-44e2-8b6d-1c56683744fe","order_by":1,"name":"Fatma Sevinç Şengül","email":"","orcid":"","institution":"Sağlık Bilimleri Üniversitesi","correspondingAuthor":false,"prefix":"","firstName":"Fatma","middleName":"Sevinç","lastName":"Şengül","suffix":""},{"id":634341486,"identity":"6c856081-1370-40e8-a068-f493bc5e61aa","order_by":2,"name":"Okan Yıldız","email":"","orcid":"","institution":"Sağlık Bilimleri Üniversitesi","correspondingAuthor":false,"prefix":"","firstName":"Okan","middleName":"","lastName":"Yıldız","suffix":""},{"id":634341496,"identity":"b5c39e2f-11ae-4b0c-96c1-45c5c33d8df9","order_by":3,"name":"Alper Güzeltaş","email":"","orcid":"","institution":"Sağlık Bilimleri Üniversitesi","correspondingAuthor":false,"prefix":"","firstName":"Alper","middleName":"","lastName":"Güzeltaş","suffix":""}],"badges":[],"createdAt":"2026-04-24 20:23:14","currentVersionCode":1,"declarations":"","doi":"10.21203/rs.3.rs-9520548/v1","doiUrl":"https://doi.org/10.21203/rs.3.rs-9520548/v1","draftVersion":[],"editorialEvents":[],"editorialNote":"","failedWorkflow":false,"files":[{"id":108633312,"identity":"69741683-731f-427e-b63e-fbcf7b0aef74","added_by":"auto","created_at":"2026-05-06 17:10:52","extension":"png","order_by":1,"title":"Figure 1","display":"","copyAsset":false,"role":"figure","size":10559195,"visible":true,"origin":"","legend":"\u003cp\u003e\u003cstrong\u003eA: \u003c/strong\u003eTransthoracic echocardiography showing direct inflow from right atrium into both ventricles\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eB:\u003c/strong\u003e Intraoperative view of right AV valve’s left and right orifices\u003c/p\u003e","description":"","filename":"Figure1Aand1B.png","url":"https://assets-eu.researchsquare.com/files/rs-9520548/v1/08a2d24c6c72870a4ee5bd5e.png"},{"id":108814588,"identity":"5fa7101e-afb1-4bc8-89a8-1d57bbad16f3","added_by":"auto","created_at":"2026-05-08 16:18:34","extension":"pdf","order_by":0,"title":"","display":"","copyAsset":false,"role":"manuscript-pdf","size":9965331,"visible":true,"origin":"","legend":"","description":"","filename":"manuscript.pdf","url":"https://assets-eu.researchsquare.com/files/rs-9520548/v1/64789307-066a-474e-9122-28cb7032dc6a.pdf"},{"id":108633254,"identity":"794574ca-0021-45e3-8b71-3837a416c438","added_by":"auto","created_at":"2026-05-06 17:10:45","extension":"mp4","order_by":0,"title":"","display":"","copyAsset":false,"role":"supplement","size":21381839,"visible":true,"origin":"","legend":"","description":"","filename":"DORAechoVideo1.mp4","url":"https://assets-eu.researchsquare.com/files/rs-9520548/v1/05c92153950a7a124a9cd7a2.mp4"},{"id":108633380,"identity":"3c098a0f-8957-4e2d-a804-a6a0de73a1a5","added_by":"auto","created_at":"2026-05-06 17:10:59","extension":"mp4","order_by":1,"title":"","display":"","copyAsset":false,"role":"supplement","size":22072828,"visible":true,"origin":"","legend":"","description":"","filename":"DORAoperationVideo2.mp4","url":"https://assets-eu.researchsquare.com/files/rs-9520548/v1/5b185ac2f625cf37aab9c86b.mp4"}],"financialInterests":"No competing interests reported.","formattedTitle":"Double Outlet Right Atrium Associated with Large Atrial and Ventricular Septal Defects in a Neonate with Down Syndrome: A Case Illustrated by Imaging and Surgical Findings","fulltext":[{"header":"Introduction","content":"\u003cp\u003eDouble outlet right atrium (DORA) is an extremely rare congenital cardiac malformation, characterized by anomalous atrioventricular septation resulting in both ventricles receiving direct inflow from the right atrium. This unusual anomaly is associated with significant hemodynamic disturbances and typically presents in the neonatal period with cardiopulmonary symptoms. DORA may coexist with a wide spectrum of congenital heart defects including atrial septal defect (ASD), ventricular septal defect (VSD), atrioventricular septal defect (AVSD), double outlet right ventricle (DORV), and transposition of the great arteries (TGA). Genetic syndromes such as trisomy 21, heterotaxy syndromes, and 22q11 deletion are commonly associated with this anomaly (\u003cspan additionalcitationids=\"CR2\" citationid=\"CR1\" class=\"CitationRef\"\u003e1\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR3\" class=\"CitationRef\"\u003e3\u003c/span\u003e).\u003c/p\u003e \u003cp\u003eWe present a rare case of DORA accompanied by a large perimembranous VSD (extending from the inlet to the outlet) and secundum ASD in a neonate with confirmed Down syndrome. To our knowledge, the Transthoracic echocardiographic (TTE) and intraoperative documentation in this case contributes valuable visual insights to the limited existing literature on this anomaly.\u003c/p\u003e"},{"header":"Case presentation","content":"\u003cp\u003eA female neonate was born at 37\u0026thinsp;+\u0026thinsp;3 weeks of gestation with a birth weight of 3380 grams via spontaneous vaginal delivery. On postnatal day 3, she developed respiratory distress and was admitted to the neonatal intensive care unit. Phenotypic features were consistent with Down syndrome, and karyotyping confirmed a diagnosis of trisomy 21 (47, XX\u0026thinsp;+\u0026thinsp;21).\u003c/p\u003e \u003cp\u003eInitial TTE examination revealed a large secundum-type ASD and a large perimembranous VSD (extending from the inlet to the outlet). The patient was referred to our pediatric cardiology department for further evaluation after stabilization and discharge.\u003c/p\u003e \u003cp\u003eAt 1 month of age, she was referred to our clinic, weighing 3600 grams, indicating a weight gain of only 220 grams in the first month of life. Clinical examination revealed a respiratory rate of 52 breaths per minute, a systolic murmur graded 4\u0026ndash;5/6, and oxygen saturation of %97 on room air. Electrocardiography showed sinus tachycardia (145 bpm) with right axis deviation. Chest X-ray demonstrated cardiomegaly with a cardiothoracic index of 55\u0026ndash;60% and increased pulmonary vascular markings. TTE confirmed a large (8mm) secundum-type ASD, a wide perimembranous VSD (with a color Doppler jet width of up to 6 mm and multiple flow streams), and a unique anomaly: both the right and left ventricles received direct inflow from the right atrium, consistent with DORA (Fig.\u0026nbsp;\u003cspan refid=\"Fig2\" class=\"InternalRef\"\u003e1\u003c/span\u003eA, Video 1). The interatrial septum appeared malposed to the left.\u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003cp\u003eThe patient was started on oral anti-congestive medications and high-calorie nutritional supplementation, with monthly follow-up planned at the pediatric cardiology outpatient clinic.\u003c/p\u003e \u003cp\u003eDuring follow-up, enlargement of the left heart chambers and increased pulmonary blood flow were noted. In order to prevent the progression to irreversible pulmonary vascular resistance and the risk of heart failure secondary to chronic volume overload, surgical correction was scheduled at 7 months of age, when the patient weighed approximately 9 kilograms.\u003c/p\u003e \u003cp\u003eIntraoperative examination revealed leftward deviation of the interatrial septum and a crossing chord emerging from the left ventricle and attaching to the tip of the right AV valve apparatus. The right AV valve anteroseptal commissure was detached from the annulus to leave the left-sided chord in place, and the detached segment of the tricuspid valve was resutured to the annulus. The tricuspid valve leaflets were approximated at the midline, and cleft-like structures were closed individually, resulting in mild residual regurgitation. Following a transverse incision of the interatrial septum, the left AV valve was evaluated and showed no evidence of stenosis or insufficiency. Assessment of the outlet VSD demonstrated approximately 50% anteroseptal malalignment, which was repaired using a pericardial patch. (Fig.\u0026nbsp;\u003cspan refid=\"Fig2\" class=\"InternalRef\"\u003e1\u003c/span\u003eB, Video 2). These findings confirmed the preoperative diagnosis of DORA.\u003c/p\u003e \u003cp\u003eThe patient was extubated after 48 hours and transferred to the pediatric ward on postoperative day 4. She was discharged home in stable condition after 4 days of uneventful inpatient follow-up. At her outpatient follow-up, she remained clinically stable with only mild residual regurgitation in both AV valves and required no medical therapy.\u003c/p\u003e"},{"header":"Discussion","content":"\u003cp\u003eDouble outlet right atrium is an extremely rare congenital anomaly characterized by anomalous drainage of the right atrium into both ventricles due to atrioventricular septal maldevelopment. (\u003cspan citationid=\"CR1\" class=\"CitationRef\"\u003e1\u003c/span\u003e, \u003cspan citationid=\"CR2\" class=\"CitationRef\"\u003e2\u003c/span\u003e). Previous studies have emphasized the risk of misdiagnosis as atrioventricular septal defect, particularly in patients with trisomy 21 (\u003cspan citationid=\"CR2\" class=\"CitationRef\"\u003e2\u003c/span\u003e). Therefore, recognition of DORA as a distinct anatomical entity is essential to ensure accurate diagnosis and to guide surgical strategy.\u003c/p\u003e \u003cp\u003eTTE generally provides sufficient diagnostic information, but advanced modalities such as cardiac magnetic resonance imaging or computed tomography may be required in patients with complex anatomy (\u003cspan citationid=\"CR1\" class=\"CitationRef\"\u003e1\u003c/span\u003e, \u003cspan citationid=\"CR4\" class=\"CitationRef\"\u003e4\u003c/span\u003e). While TTE remains the cornerstone of diagnosis, detailed assessment of atrial inflow and septal alignment is critical to distinguish DORA from other atrioventricular septal malformations. Transthoracic and transesophageal echocardiography, complemented by three-dimensional imaging, are critical in delineating atrial septal malalignment and the atrioventricular valve attachments. Advanced imaging modalities such as cardiac CT or MRI can further aid in defining atrial inflow pathways and excluding AVSD, in which a common atrioventricular junction and bridging leaflets are typically present. In our case, TTE clearly demonstrated the anomalous atrial inflow and septal malalignment, which was crucial for preoperative planning.\u003c/p\u003e \u003cp\u003eIn our patient, a predominant left-to-right shunt pattern was present due to the coexistence of DORA with a large secundum atrial septal defect and a perimembranous ventricular septal defect. Although the right atrium was observed to open into both ventricles because of DORA, it predominantly drained into the right ventricle. Therefore, the amount of deoxygenated blood passing from the right atrium to the left ventricle was limited, and no significant clinical cyanosis was observed. Similar findings have been described in previous case reports (\u003cspan citationid=\"CR3\" class=\"CitationRef\"\u003e3\u003c/span\u003e).\u003c/p\u003e \u003cp\u003eSurgical management depends on the specific anatomical configuration, with reported techniques including closure of abnormal atrioventricular orifices, reconstruction of the interatrial septum, and repair of associated lesions (\u003cspan citationid=\"CR1\" class=\"CitationRef\"\u003e1\u003c/span\u003e, \u003cspan citationid=\"CR4\" class=\"CitationRef\"\u003e4\u003c/span\u003e). In our patient, surgical repair consisting of closure of the septal defects and anatomical realignment of the atrial septum was successfully performed, resulting in favorable postoperative outcome.\u003c/p\u003e \u003cp\u003eDORA represents a unique entity within the spectrum of atrioventricular connection anomalies. Our case, presenting with DORA in association with a large secundum atrial septal defect and a perimembranous ventricular septal defect, illustrates the potential for significant hemodynamic compromise in the neonatal period. The term \u0026ldquo;hemodynamic compromise\u0026rdquo; in DORA refers to the potential for early postnatal circulatory instability due to atrioventricular malalignment, which may lead to unbalanced inflow, atrioventricular valve regurgitation, or decreased pulmonary blood flow. In our patient, large interatrial and interventricular communications maintained balanced filling and effective mixing, preventing neonatal decompensation. The literature underscores its frequent misdiagnosis as atrioventricular septal defect, particularly in syndromic infants, and emphasizes the heterogeneity of clinical presentation (\u003cspan additionalcitationids=\"CR2 CR3 CR4\" citationid=\"CR1\" class=\"CitationRef\"\u003e1\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR5\" class=\"CitationRef\"\u003e5\u003c/span\u003e).\u003c/p\u003e \u003cp\u003eThe diagnosis of DORA is not determined solely by the degree of tricuspid valve override but by the malalignment of the interatrial septum and the drainage pattern of the right atrium into both ventricles.\u003c/p\u003e \u003cp\u003eIn our patient, echocardiographic findings demonstrated that the right atrium drained directly into both ventricles, predominantly into the right ventricle and only partially into the left ventricle through a smaller orifice. This pattern was caused by leftward deviation of the interatrial septum, rather than true tricuspid override. Although both tricuspid overriding and DORA demonstrate flow from the right atrium into both ventricles, they possess distinct anatomic characteristics.\u003c/p\u003e \u003cp\u003eBoth entities primarily result from malalignment of the atrial and ventricular septa; however, in DORA, two separate atrioventricular valve orifices are identified, corresponding to distinct right and left AV connections. In contrast, tricuspid overriding represents a single right atrioventricular connection with the tricuspid valve overriding the ventricular septum. These distinctions have been summarized in previous comparative studies (\u003cspan citationid=\"CR6\" class=\"CitationRef\"\u003e6\u003c/span\u003e).\u003c/p\u003e \u003cp\u003eThese findings were consistent across echocardiographic and intraoperative evaluations, confirming double outlet right atrium (DORA) anatomy.\u003c/p\u003e"},{"header":"Conclusion","content":"\u003cp\u003eEarly recognition and individualized surgical correction, including septal closure and anatomical realignment, are essential for achieving optimal outcomes. Our case contributes to the limited evidence based on this rare condition and highlights the importance of heightened awareness among pediatric cardiologists and congenital heart surgeons.\u003c/p\u003e"},{"header":"Declarations","content":" \u003cp\u003eWritten informed consent for publication of this case report and any accompanying images was obtained from the patient\u0026rsquo;s parents.\u003c/p\u003e\u003cp\u003e \u003cstrong\u003eData Sharing Statement\u003c/strong\u003e \u003cp\u003eThe data that support the findings of this study are available from the corresponding author upon reasonable request.\u003c/p\u003e \u003c/p\u003e\u003cp\u003e \u003ch2\u003eConflict of Interest:\u003c/h2\u003e \u003cp\u003e The authors declared no conflicts of interest with respect to the authorship and/or publication of this article.\u003c/p\u003e \u003c/p\u003e\u003ch2\u003eFunding:\u003c/h2\u003e \u003cp\u003eThe authors received no financial support for the research and/or authorship of this article.\u003c/p\u003e\u003ch2\u003eAuthor Contribution\u003c/h2\u003e\u003cp\u003eAuthor Contributions: Designed the article: M.N.; Collected the data: M.N, F.S.S.; Reviewed literature: M.N, O.Y; Writed the article: F.S.S., M.N; Made critical review: A.G.\u003c/p\u003e"},{"header":"References","content":"\u003col\u003e\u003cli\u003e\u003cspan\u003e- Ambra M, Nuri HA, Pome G, Marasini M, Francesco S (2020) Double-outlet right atrium: review of a rare anomaly with an exemplary case. World J Pediatr Congenit Heart Surg 11(1):79\u0026ndash;84\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003e- Sivakumar K, Mohanty S, Varghese R (2021) Double-outlet right atrium \u0026ndash; a rare and easily misdiagnosed entity. J Indian Acad Echocardiogr Cardiovasc Imaging 5:233\u0026ndash;235\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003e- Tanıdır IC, \u0026Ccedil;ınar B, G\u0026uuml;zeltaş A (2021) Double-outlet right atrium in an asymptomatic 8-year-old girl. Turk Kardiyol Dern Ars 49(1):86\u0026ndash;88\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003e- Thomas E, Zacharias S, Kandachar PS, Al-Maskary S (2020) Double outlet right atrium\u0026mdash;A bridge across the bridging leaflets. J Card Surg 35(12):3596\u0026ndash;3600\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003e- Borghol W, Alfaksh F, Karaja S, Barakat L, Takkem S (2025) An isolated double-inlet right ventricular malformation: a case report and review of the literature. \u003cem\u003eJ Med Case Rep\u003c/em\u003e. ;19(1):229. Published 2025 May 17. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003e10.1186/s13256-025-05300-4\u003c/span\u003e\u003cspan address=\"10.1186/s13256-025-05300-4\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003e- Edwin F, Kinsley RH, Mamorare HM, Govendrageloo K (2012) The spectrum of double-outlet right atrium including hearts with three atrioventricular valves. Eur J Cardiothorac Surg 41(4):947\u0026ndash;949. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003e10.1093/ejcts/ezr073\u003c/span\u003e\u003cspan address=\"10.1093/ejcts/ezr073\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e\u003c/ol\u003e"}],"fulltextSource":"","fullText":"","funders":[],"hasAdminPriorityOnWorkflow":false,"hasManuscriptDocX":true,"hasOptedInToPreprint":true,"hasPassedJournalQc":"","hasAnyPriority":true,"hideJournal":true,"highlight":"","institution":"","isAcceptedByJournal":false,"isAuthorSuppliedPdf":false,"isDeskRejected":"","isHiddenFromSearch":false,"isInQc":false,"isInWorkflow":false,"isPdf":false,"isPdfUpToDate":true,"isWithdrawnOrRetracted":false,"journal":{"display":true,"email":"[email protected]","identity":"researchsquare","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":true,"externalIdentity":"","sideBox":"","snPcode":"","submissionUrl":"/submission","title":"Research Square","twitterHandle":"researchsquare","acdcEnabled":true,"dfaEnabled":false,"editorialSystem":"","reportingPortfolio":"","inReviewEnabled":false,"inReviewRevisionsEnabled":true},"keywords":"","lastPublishedDoi":"10.21203/rs.3.rs-9520548/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-9520548/v1","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"\u003cp\u003eDouble outlet right atrium (DORA) is an exceptionally rare congenital cardiac anomaly characterized by direct right atrial inflow into both ventricles, often resulting in significant hemodynamic compromise. We report a case of DORA in a neonate with Down syndrome and large coexisting ASD and VSD, who underwent successful surgical repair at 7 months of age. This case, supported by echocardiographic and intraoperative documentation, highlights the clinical presentation, diagnostic challenges, and surgical findings of this rare anomaly.\u003c/p\u003e","manuscriptTitle":"Double Outlet Right Atrium Associated with Large Atrial and Ventricular Septal Defects in a Neonate with Down Syndrome: A Case Illustrated by Imaging and Surgical Findings","msid":"","msnumber":"","nonDraftVersions":[{"code":1,"date":"2026-05-06 17:10:36","doi":"10.21203/rs.3.rs-9520548/v1","editorialEvents":[{"type":"communityComments","content":0}],"status":"published","journal":{"display":true,"email":"[email protected]","identity":"researchsquare","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":true,"externalIdentity":"","sideBox":"","snPcode":"","submissionUrl":"/submission","title":"Research Square","twitterHandle":"researchsquare","acdcEnabled":true,"dfaEnabled":false,"editorialSystem":"","reportingPortfolio":"","inReviewEnabled":false,"inReviewRevisionsEnabled":true}}],"origin":"","ownerIdentity":"18846c2f-379a-497b-8579-9cc02ef65358","owner":[],"postedDate":"May 6th, 2026","published":true,"recentEditorialEvents":[{"type":"decision","content":"Rejected","date":"2026-05-04T18:25:26+00:00","index":"","fulltext":""}],"rejectedJournal":[],"revision":"","amendment":"","status":"posted","subjectAreas":[],"tags":[],"updatedAt":"2026-05-08T15:26:02+00:00","versionOfRecord":[],"versionCreatedAt":"2026-05-06 17:10:36","video":"","vorDoi":"","vorDoiUrl":"","workflowStages":[]},"version":"v1","identity":"rs-9520548","journalConfig":"researchsquare"},"__N_SSP":true},"page":"/article/[identity]/[[...version]]","query":{"redirect":"/article/rs-9520548","identity":"rs-9520548","version":["v1"]},"buildId":"XKTyCvWXoU3ODBz1xrDgd","isFallback":false,"isExperimentalCompile":false,"dynamicIds":[84888],"gssp":true,"scriptLoader":[]}