Annals of Cardiac Anaesthesia Annals of Cardiac Anaesthesia Annals of Cardiac Anaesthesia
Home | About us | Editorial Board | Search | Ahead of print | Current Issue | Archives | Submission | Subscribe | Advertise | Contact | Login 
Users online: 1017 Small font size Default font size Increase font size Print this article Email this article Bookmark this page


    Advanced search

    Similar in PUBMED
   Search Pubmed for
   Search in Google Scholar for
    Email Alert *
    Add to My List *
* Registration required (free)  

    Article Figures

 Article Access Statistics
    PDF Downloaded144    
    Comments [Add]    
    Cited by others 3    

Recommend this journal


Table of Contents
Year : 2012  |  Volume : 15  |  Issue : 2  |  Page : 161-162
Anomalous ridge on the left atrial side of the atrial septum

1 Division of Cardiovascular Diseases, Department of Internal Medicine, University of Cincinnati; Division of Cardiology, Cincinnati VA Medical Center, Cincinnati, OH, USA
2 Division of Cardiovascular Diseases, Department of Internal Medicine, University of Cincinnati, Cincinnati, OH, USA
3 Division of Cardiology, Cincinnati VA Medical Center, Cincinnati, OH, USA

Click here for correspondence address and email

Date of Web Publication16-Apr-2012

How to cite this article:
Shizukuda Y, Muth J, Chaney C, Attari M. Anomalous ridge on the left atrial side of the atrial septum. Ann Card Anaesth 2012;15:161-2

How to cite this URL:
Shizukuda Y, Muth J, Chaney C, Attari M. Anomalous ridge on the left atrial side of the atrial septum. Ann Card Anaesth [serial online] 2012 [cited 2023 Feb 1];15:161-2. Available from:

A 75-year-old male with a history of persistent atrial fibrillation, type II diabetes mellitus, hypertension and hypercholesterolemia underwent transesophageal echocardiography (TEE) to evaluate for a left atrial appendage thrombus prior to direct current cardioversion. The TEE was performed using a real-time 3-dimensional (3D) TEE probe connected to the iE 33 Philips ultrasound system (Philips Healthcare, Andovor, MA, USA). The 3D TEE revealed a ridge-like structure on the left atrial side of the atrial septum protruding into the left atrial lumen [Figure 1]a. This ridge was formed along the superior edge of the oval fossa in the left atrium, and extended to the left atrial free wall medially and superiorly [Figure 1]b. This ridge-like structure overhung posteriorly, creating a hollow-like structure [Figure 1]c and d. Although we did not perform an agitated saline contrast study, which is more sensitive than color Doppler, to evaluate a right to left atrial shunt, the color Doppler interrogation of this ridge did not reveal interatrial shunting. No thrombus or spontaneous echo contrast was noted beneath the overhung area. The atrial septum appeared normal from the right atrial side [Figure 2]a and b.
Figure 1: In panel a, an overhanging membrane-like ridge is demonstrated in the mid esophageal view of 2-dimensional transesophageal echocardiography (TEE). The white arrow indicates a ridge-like structure. AS - atrial septum; RA - right atrium; LA - left atrium; AA - ascending thoracic aorta. In panel b, superiorly coursing membrane-like ridge in the left atrium is demonstrated in the en face surgeon's view (looking at the supine patient from head to toe from the left side of the patient) with full-volume 3-dimensional TEE. The black arrow indicates a ridge-like structure. The arrow heads denote the spatial orientation. LA - left atrium; RA - right atrium; AV - aortic valve; OF - oval fossa; SVC - superior vena cava; Ant - anterior side of the patient; Rt - right side of the patient; *stitch artifact due to respiratory motion. In panels c and d, a folding membrane-like character creating a slit of the ridge structure (black arrow) is demonstrated in 3-dimensional TEE. The arrow heads denote the spatial orientation. AS - atrial septum; RA - right atrium; LA - left atrium; OF - oval fossa; ant, anterior side of the patient; rt - right side of the patient; sup - head side of the patient; inf - back side of the patient

Click here to view
Figure 2: The views of atrial septum (AS) from the right atrium are shown with 3-dimensional transesophageal echocardiography. The AS is viewed from the right atrial free wall in panel (a) The oval fossa (OF) is demonstrated as slight depression of the atrial septum. The atrial septum is viewed in standard bicaval view in panel. (b) SVC denotes superior vena cava. The ridge formation is depicted by a white arrow head

Click here to view

In contrast to the ridge-like structures of the right atrium, such as an  Eustachian valve More Details or crista terminalis, ridge-like structures on the left atrial side have not been well described. [1],[2] In the left atrial side of the atrial septum, redundancy of atrial septal membrane forming the oval fossa is often noted, and atrial septal aneurysm is common. [1],[2] Sweeny et al. describe a network of muscular trabeculations that can be seen in the left atrial septum. Some of these may be seen along the anterior border of the oval fossa representing the remnants of the ostium secudum, and have been named the cresentic muscular arch. [3],[4] However, a prominent membrane-like ridge formation along the oval fossa that overhangs and extends to the atrial free wall superiorly has not been clearly documented in the previous literature. In addition, this variation could interfere with navigating guiding wires and catheters in the left atrium through transeptal approach. Recently, two discrete types of mesenchymal cells have been identified that form the mesenchymal cap that closes the primary atrial foramen by fusing with the arterioventricular cushions. [5] One population is from the endocardium and the other is from the dorsal mesocardium outside the heart, indicating that both intracardiac and extracardiac mesenchymal cells participate in the formation of the atrial septum. [5] This study underscores the complexity of atrial septum formation and a need for further understanding of this embryonic development. Our case is a very rare anomaly. The number of cardiac patients who undergo inverventional transeptal approach has risen substantially over the past few years, further underlying the importance of understanding left atrial anatomy and anomalies. Delineation of complex atrial septal structures before such procedures by TEE with the aid of 3-dimensional TEE informs the cardiologist of potential procedural challenges and improves patient safety. [6]

   References Top

1.Zabalgoitia M, Norris LP, Garcia M. Atrial septal aneurysm as a potential source of neurological ischemic events. Am J Card Imaging 1994;8:39-44.  Back to cited text no. 1
2.Anderson RH, Cook AC. The structure and components of the atrial chambers. Europace 2007;9 Suppl 6:63-9.  Back to cited text no. 2
3.Sweeney LJ, Rosenquist GC. The normal anatomy of the atrial septum in the human heart. Am Heart J 1979;98:194-9.  Back to cited text no. 3
4.Faletra FF, Nucifora G, Ho SY. Imaging the atrial septum using real-time three-dimensional transesophageal echocardiography: Technical tips, normal anatomy, and its role in transseptal puncture. J Am Soc Echocardiogr 2011;24:593-9.  Back to cited text no. 4
5.Mommersteeg MT, Soufan AT, de Lange FJ, van den Hoff MJ, Anderson RH, Christoffels VM, et al. Two distinct pools of mesenchyme contribute to the development of the atrial septum. Circ Res 2006;99:351-3.  Back to cited text no. 5
6.Hung J, Lang R, Flachskampf F, Shernan SK, McCulloch ML, Adams DB, et al. 3D echocardiography: A review of the current status and future directions. J Am Soc Echocardiogr 2007;20:213-33.  Back to cited text no. 6

Correspondence Address:
Yukitaka Shizukuda
Division of Cardiovascular Diseases, Department of Medicine, University Hospital, University of Cincinnati, 231 Albert Sabin Way, ML 0542 Cincinnati, OH 45267 0542
Login to access the Email id

Source of Support: None, Conflict of Interest: None

DOI: 10.4103/0971-9784.95083

Rights and Permissions


  [Figure 1], [Figure 2]

This article has been cited by
1 An Atrial Septal Ridge Diagnosed by Transesophageal Echocardiography
Rowa H. Attar, Amr Telmesani, Nadeen N. Faza
Methodist DeBakey Cardiovascular Journal. 2022; 18(1): 14
[Pubmed] | [DOI]
2 Morphological Study of Fossa Ovalis in Formalin-Fixed Human Hearts and Its Clinical Importance
Monica Adriana Vaida, Caius Glad Streian, Cristina Gug, Nawwaf Sebastian Damen, Adelina Maria Jianu, Andreea Grigori?a, Laura Grigori?a
Medicina. 2021; 57(11): 1254
[Pubmed] | [DOI]
3 Ridges and Pouches: A Case Series of Anomalous Atrial Septal Fusion
David Zisa, Francesco F. Faletra, Benjamin S. Wessler, Neil J. Halin, Pranitha Reddy, Ayan R. Patel, Natesa G. Pandian
CASE. 2020; 4(1): 7
[Pubmed] | [DOI]