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A Rare Atrial Septal Malformation
DIAGNOSTIC DILEMMA Paul S. Pagel, MD, PhD Section Editor
A Rare Atrial Septal Malformation Arora Ram Nishant, MD, FIACTA, and Madan Mohan Maddali, MD
Fig 1. Midesophageal 4-chamber view with the white arrow showing an elongated passage in the atrial septum. RA, right atrium; LA, left atrium; RV, right ventricle.
A From the Department of Anesthesia, Royal Hospital, Muscat, OmanDepartment of Anesthesia, Royal Hospital, Muscat, Oman. Address reprint requests to Madan Mohan Maddali, MD, Royal Hospital, P.B.No: 1331, P.C: 111, Seeb, Muscat, Sultanate of Oman. E-mail: [email protected] © 2015 Elsevier Inc. All rights reserved. 1053-0770/2602-0033$36.00/0 http://dx.doi.org/10.1053/j.jvca.2015.02.017 Key words: atrial septum/pathology, echocardiography, transesophageal 1100
44-YEAR-OLD woman (63 kg, 148 cm, BMI 28.7) with antiphospholipid antibody syndrome presented with progressively increasing congestive heart failure. She had a history of idiopathic thrombocytopenia purpura, deep vein thrombosis, and multiple abortions. Transthoracic echocardiography showed severe mitral regurgitation with an eccentric regurgitant jet reaching the roof of an undilated left atrium. A patent foramen ovale (PFO) also was diagnosed. A mitral valve replacement was planned. Intraoperative transesophageal echocardiography revealed the following images of the interatrial septum (Figs 1 and 2) (Video clips 1 and 2). What is the diagnosis?
Journal of Cardiothoracic and Vascular Anesthesia, Vol 29, No 4 (August), 2015: pp 1100–1102
ATRIAL SEPTUM
1101
Fig 2. Modified bicaval view showing an elongated defect in the interatrial septum as indicated by the white arrow. RA, right atrium; LA, left atrium; TV, tricuspid valve; RV, right ventricle.
DIAGNOSIS: DOUBLE-MEMBRANE ATRIAL SEPTUM WITH PATENT FORAMEN OVALE
The initial impression of the atrial septal abnormality during the intraoperative transesophageal echocardiography was that it could be a variant of cor-triatrium or an aneurysmal interatrial septum. The possibility of cor-triatrium was excluded as the membrane in cor-triatrium is perpendicular to the atrial septum and not parallel to the atrial septum as was the case in this patient. It was not considered to be an aneurysmal interatrial septum as it was not a localized outpouching. The diagnosis of a double-membrane atrial septum with PFO with a left-to-right shunt was the one at which the authors arrived by exclusion. This was confirmed by direct visualization of the defect by the surgeon. The mitral valve was replaced with a 23-size St. Jude Medical mechanical valve (St. Jude Medical, Inc., St. Paul, MN). The gap between the 2 layers of the interatrial septum was probed, and the tunnel-like defect was obliterated by suturing the 2 layers together using a 4/0 polypropylene suture to eliminate any deadspace with potential for thrombus formation. Both procedures were performed on cardiopulmonary bypass. A double-membrane atrial septum that distinguishes the midline interatrial chamber between the 2 atria by a parallel double-layered atrial septal structure is an extremely rare congenital anomaly. Septum primum separates the interatrial space from the left atrium, and an accessory septal structure distinguishes this space from the right atrium. This accessory septal structure is presumed to be a persistent left venous valve
attached to the sinus venosus in the fetal period.1 Some authors have suggested that this anomaly could be a result of failure of the septum primum and septum secundum to fuse or could be due to the persistence of primitive valves like the Eustachian valve with chiari network.2 The interatrial space usually communicates with the left atrium through a PFO. This interatrial space communicates with the right atrium through an accessory atrial septal fenestration. The 2 openings, (ie, the PFO into the left atrium and the accessory atrial septal fenestration) are found at different levels.3 In this patient, the openings were found superior and inferior to each other. Normally, during the intrauterine period, as part of fetal circulation, blood is shunted right-to-left through a foramen ovale. The presence of a double-walled interatrial septum does not permit adequate right-to-left shunt flow through the foramen ovale, resulting in varying degrees of left heart hypoplasia and anomalies associated with mitral valve and pulmonary venous structures that could manifest in later life as signs of an underdeveloped left ventricle.3 This patient, although having reached adulthood, did not have any features of left heart hypoplasia. If left untreated, an isolated interatrial chamber might be a nidus for thrombus formation and a source of systemic embolization, causing potentially lethal neurologic complications as transient ischemic attacks or stroke.4 Hence, it is advisable to close the defect. In this patient, there was no dilemma about the concomitant surgical closure of the atrial septal defect during mitral valve
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replacement, considering the hypercoagulable state associated with her antiphospholipid antibody syndrome and her prior history of deep vein thrombosis. If practitioners did not attend to the PFO, there was the real danger of a paradoxic embolism in this patient at a later stage. The actual dilemma was about the nomenclature that should be applied to name the interatrial septal anomaly. Whether it should be named a variant of cortriatrium or called a bilaminar PFO or a double-membrane atrial septum with PFO was the debatable point. Most often, a
double-membrane atrial septum is usually an incidental finding.5 Intraoperative transesophageal echocardiography helps in the identification of the exact details of the defect and precisely defines the important anatomic and blood flow features. APPENDIX A. SUPPORTING INFORMATION
Supplementary material cited in this article is available online at doi:10.1053/j.jvca.2015.02.017.
REFERENCES 1. Van Praagh R, Corsini I: Cor triatriatum: Pathologic anatomy and a consideration of morphogenesis based on 13 postmortem cases and a study of normal development of the pulmonary vein and atrial septum in 83 human embryos. Am Heart J 78: 379-405, 1969 2. Roberson DA, Javois AJ, Cui W, et al: Double atrial septum with persistent interatrial space: Echocardiographic features of a rare atrial septal malformation. J Am Soc Echocardiogr 19:1175-1181, 2006
3. Kim IS, Jin MN, Song C, et al: The case of isolated double atrial septum with persistent interatrial space. J Cardiovasc Ultrasound 21: 197-199, 2013 4. Seyfert H, Bohlscheid V, Bauer B: Double atrial septum with persistent interatrial space and transient ischaemic attack. Eur J Echocardiogr 9:707-708, 2008 5. Szili-Torok T, Kimman G, Theuns D, et al: Transseptal left heart catheterisation guided by intracardiac echocardiography. Heart 86: E11, 2001
A Rare Atrial Septal Malformation Arora Ram Nishant, MD, FIACTA, and Madan Mohan Maddali, MD
Fig 1. Midesophageal 4-chamber view with the white arrow showing an elongated passage in the atrial septum. RA, right atrium; LA, left atrium; RV, right ventricle.
A From the Department of Anesthesia, Royal Hospital, Muscat, OmanDepartment of Anesthesia, Royal Hospital, Muscat, Oman. Address reprint requests to Madan Mohan Maddali, MD, Royal Hospital, P.B.No: 1331, P.C: 111, Seeb, Muscat, Sultanate of Oman. E-mail: [email protected] © 2015 Elsevier Inc. All rights reserved. 1053-0770/2602-0033$36.00/0 http://dx.doi.org/10.1053/j.jvca.2015.02.017 Key words: atrial septum/pathology, echocardiography, transesophageal 1100
44-YEAR-OLD woman (63 kg, 148 cm, BMI 28.7) with antiphospholipid antibody syndrome presented with progressively increasing congestive heart failure. She had a history of idiopathic thrombocytopenia purpura, deep vein thrombosis, and multiple abortions. Transthoracic echocardiography showed severe mitral regurgitation with an eccentric regurgitant jet reaching the roof of an undilated left atrium. A patent foramen ovale (PFO) also was diagnosed. A mitral valve replacement was planned. Intraoperative transesophageal echocardiography revealed the following images of the interatrial septum (Figs 1 and 2) (Video clips 1 and 2). What is the diagnosis?
Journal of Cardiothoracic and Vascular Anesthesia, Vol 29, No 4 (August), 2015: pp 1100–1102
ATRIAL SEPTUM
1101
Fig 2. Modified bicaval view showing an elongated defect in the interatrial septum as indicated by the white arrow. RA, right atrium; LA, left atrium; TV, tricuspid valve; RV, right ventricle.
DIAGNOSIS: DOUBLE-MEMBRANE ATRIAL SEPTUM WITH PATENT FORAMEN OVALE
The initial impression of the atrial septal abnormality during the intraoperative transesophageal echocardiography was that it could be a variant of cor-triatrium or an aneurysmal interatrial septum. The possibility of cor-triatrium was excluded as the membrane in cor-triatrium is perpendicular to the atrial septum and not parallel to the atrial septum as was the case in this patient. It was not considered to be an aneurysmal interatrial septum as it was not a localized outpouching. The diagnosis of a double-membrane atrial septum with PFO with a left-to-right shunt was the one at which the authors arrived by exclusion. This was confirmed by direct visualization of the defect by the surgeon. The mitral valve was replaced with a 23-size St. Jude Medical mechanical valve (St. Jude Medical, Inc., St. Paul, MN). The gap between the 2 layers of the interatrial septum was probed, and the tunnel-like defect was obliterated by suturing the 2 layers together using a 4/0 polypropylene suture to eliminate any deadspace with potential for thrombus formation. Both procedures were performed on cardiopulmonary bypass. A double-membrane atrial septum that distinguishes the midline interatrial chamber between the 2 atria by a parallel double-layered atrial septal structure is an extremely rare congenital anomaly. Septum primum separates the interatrial space from the left atrium, and an accessory septal structure distinguishes this space from the right atrium. This accessory septal structure is presumed to be a persistent left venous valve
attached to the sinus venosus in the fetal period.1 Some authors have suggested that this anomaly could be a result of failure of the septum primum and septum secundum to fuse or could be due to the persistence of primitive valves like the Eustachian valve with chiari network.2 The interatrial space usually communicates with the left atrium through a PFO. This interatrial space communicates with the right atrium through an accessory atrial septal fenestration. The 2 openings, (ie, the PFO into the left atrium and the accessory atrial septal fenestration) are found at different levels.3 In this patient, the openings were found superior and inferior to each other. Normally, during the intrauterine period, as part of fetal circulation, blood is shunted right-to-left through a foramen ovale. The presence of a double-walled interatrial septum does not permit adequate right-to-left shunt flow through the foramen ovale, resulting in varying degrees of left heart hypoplasia and anomalies associated with mitral valve and pulmonary venous structures that could manifest in later life as signs of an underdeveloped left ventricle.3 This patient, although having reached adulthood, did not have any features of left heart hypoplasia. If left untreated, an isolated interatrial chamber might be a nidus for thrombus formation and a source of systemic embolization, causing potentially lethal neurologic complications as transient ischemic attacks or stroke.4 Hence, it is advisable to close the defect. In this patient, there was no dilemma about the concomitant surgical closure of the atrial septal defect during mitral valve
1102
NISHANT AND MADDALI
replacement, considering the hypercoagulable state associated with her antiphospholipid antibody syndrome and her prior history of deep vein thrombosis. If practitioners did not attend to the PFO, there was the real danger of a paradoxic embolism in this patient at a later stage. The actual dilemma was about the nomenclature that should be applied to name the interatrial septal anomaly. Whether it should be named a variant of cortriatrium or called a bilaminar PFO or a double-membrane atrial septum with PFO was the debatable point. Most often, a
double-membrane atrial septum is usually an incidental finding.5 Intraoperative transesophageal echocardiography helps in the identification of the exact details of the defect and precisely defines the important anatomic and blood flow features. APPENDIX A. SUPPORTING INFORMATION
Supplementary material cited in this article is available online at doi:10.1053/j.jvca.2015.02.017.
REFERENCES 1. Van Praagh R, Corsini I: Cor triatriatum: Pathologic anatomy and a consideration of morphogenesis based on 13 postmortem cases and a study of normal development of the pulmonary vein and atrial septum in 83 human embryos. Am Heart J 78: 379-405, 1969 2. Roberson DA, Javois AJ, Cui W, et al: Double atrial septum with persistent interatrial space: Echocardiographic features of a rare atrial septal malformation. J Am Soc Echocardiogr 19:1175-1181, 2006
3. Kim IS, Jin MN, Song C, et al: The case of isolated double atrial septum with persistent interatrial space. J Cardiovasc Ultrasound 21: 197-199, 2013 4. Seyfert H, Bohlscheid V, Bauer B: Double atrial septum with persistent interatrial space and transient ischaemic attack. Eur J Echocardiogr 9:707-708, 2008 5. Szili-Torok T, Kimman G, Theuns D, et al: Transseptal left heart catheterisation guided by intracardiac echocardiography. Heart 86: E11, 2001