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Bifid Atrial Septal Aneurysm

Visualization with Three-Dimensional Transesophageal Echocardiography

Matyal, Robina, MD*; Warraich, Haider Javed, MD*; Panzica, Peter, MD*; Khabbaz, Kamal R., MD; Mahmood, Feroze, MD*

doi: 10.1213/ANE.0b013e3182189209
Cardiovascular Anesthesiology: Echo Rounds
Free
SDC
CME

Published ahead of print April 5, 2011

From the *Department of Anesthesiology, Critical Care and Pain Medicine, and Department of Cardiothoracic Surgery, Beth Israel Deaconess Medical Centre, Boston, Massachusetts.

Funding: None.

Supplemental digital content is available for this article. Direct URL citations appear in the printed text and are provided in the HTML and PDF versions of this article on the journal's Web site (www.anesthesia-analgesia.org).

The authors declare no conflicts of interest.

Reprints will not be available from the authors.

Patient consent statement: Consent for publication of this case has been obtained from the patient.

Address correspondence to Robina Matyal, MD, CC 454, Department of Anesthesiology, Critical Care and Pain Medicine, Beth Israel Deaconess Medical Centre, Harvard Medical School, Boston, MA 02215. Address e-mail to rmatyal@bidmc.harvard.edu.

Accepted July 19, 2010

Published ahead of print April 5, 2011

An 85-year-old female presented with episodes of presyncope and dizziness. She had a history of aortic stenosis (AS) and reported increasing paroxysms of atrial fibrillation (AF). In addition to severe AS, recent cardiac catheterization also revealed mild aortic regurgitation (AR), moderate mitral regurgitation, angiographically normal coronary arteries, and preserved left ventricular systolic function. The patient was thus referred for aortic valve (AV) replacement.

A baseline transesophageal echocardiogram (TEE) after induction of anesthesia revealed AV area of 0.8 cm2, severely deformed AV leaflets with moderate AR. Further TEE examination revealed a large atrial septal aneurysm protruding 2 cm into the right atrium in the midesophageal 4-chamber view (Fig. 1) (Video 1, see Supplemental Digital 1, http://links.lww.com/AA/A262; see Appendix for video captions). Three-dimensional (3D) imaging using “live” and “live zoom” mode with an IE-33 system and X7-2t TEE probe (Philips Medical Systems, Andover, MA) clearly revealed it to be a bifid atrial septal aneurysm (Fig. 2) (Video 2, see Supplemental Digital Content 2, http://links.lww.com/AA/A263). The atrial septal aneurysm was viewed from multiple angles. The best 3D view was obtained with the initial image of the atrial septal aneurysm in midesophageal position with the angle between 90 and 110 degrees with a simultaneous orthogonal view. During 3D image acquisition, the size of the region of interest and the elevational width (depth of the z plane) were adjusted to include the entire atrial septal aneurysm. Using 2-dimensional (2D) imaging, a right-to-left shunt across the atrial septal aneurysm was seen after injection of agitated saline contrast with Valsalva maneuver release (Video 3, see Supplemental Digital Content 3, http://links.lww.com/AA/A264). There was also severe spontaneous echo contrast in the atrial septal aneurysm (Fig. 1 inset). The patient's left ventricular systolic function was confirmed to be normal. These findings were conveyed to the surgical team and it was decided after discussion, considering among other things the advanced age of the patient, that surgical intervention should not be attempted. The patient underwent an uneventful AV replacement. Postcardiopulmonary bypass TEE showed the bioprosthetic valve to be well seated with good leaflet motion. Normal AV gradient was noted with trace AR; biventricular function remained normal, though the patient was still experiencing AF. There was resolution of the spontaneous echo contrast after separation from cardiopulmonary bypass. Because of a recurrent AF and tachy-brady syndrome, a permanent pacemaker was implanted postoperatively and the patient was discharged with anticoagulant and antiarrhythmic medication.

Figure 1

Figure 1

Figure 2

Figure 2

It is believed that atrial septal aneurysm is formed when redundant tissue around the fossa ovalis results in excessive septal wall motion during respiration. The definitions of atrial septal aneurysm are arbitrary, with authors marking cutoffs at >15-mm excursion throughout the cardiac cycle or >15-mm phasic excursion with a 15-mm base1 to >10-mm deviation from midline.2 The prevalence of atrial septal aneurysm also varies with imaging modality used—0.23% using transthoracic echocardiography and 4.6% using TEE.2 Up to 60% of patients with atrial septal aneurysm also have an associated patent foramen ovale.2 Hence, saline contrast injection with Valsalva maneuver should always be performed to diagnose or exclude shunting in the setting of atrial septal aneurysm.3 However, closure of patent foramen ovales incidentally found during cardiac surgery remains controversial.4

TEE is the “gold standard” modality for studying atrial septal pathology5 and is a useful modality when repairing atrial septal defects.6 Two-dimensional views of particular value to assess the septum include the midesophageal 4-chamber, right ventricle outflow/inflow, aortic valve short-axis view, and bicaval view. M mode can be used to measure the total excursion of redundant septal tissue throughout the cardiac cycle. Although diagnosis could be made on 2D alone, 3D TEE was able to better delineate the unique “bifid” morphology of the atrial septal aneurysm, which according to an extensive review, is an as-yet unreported finding. Bifid is defined as anything having 2 lobes with a dividing cleft. Although one can speculate on the pathogenesis, one possible anatomic explanation is a small aneurysm of the fossa ovalis, with an adjacent larger aneurysm. The clinical relevance of this finding, if any, is currently unknown.

In general, both “live zoom” and R-wave gated volumetric acquisition can be used to assess atrial septal pathology; however, R-wave gated acquisition is dependent on a regular rhythm, and “live zoom” has poorer temporal resolution. Using cropping and rotational features, the septum can be viewed “en face” from both the left and right atrial aspects. Although not replacing 2D, 3D echocardiography allows improved visualization of anatomy and aids in confirming diagnosis.

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DISCLOSURES

Name: Robina Matyal, MD.

Contribution: Manuscript preparation.

Name: Haider Javed Warraich, MD.

Contribution: Manuscript preparation.

Name: Peter Panzica, MD.

Contribution: Manuscript preparation.

Name: Kamal R. Khabbaz, MD.

Contribution: Manuscript preparation.

Name: Feroze Mahmood, MD.

Contribution: Manuscript preparation.

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REFERENCES

1. Hanley PC, Tajik AJ, Hynes JK, Edwards WD, Reeder GS, Hagler DJ, Seward JB. Diagnosis and classification of atrial septal aneurysm by two-dimensional echocardiography: report of 80 consecutive cases. J Am Coll Cardiol 1985; 6:1370–82
2. Homma S, Sacco RL. Patent foramen ovale and stroke. Circulation 2005;112:1063–72
3. Burch TM, Davidson MF, Pereira SJ. Use of transesophageal echocardiography in the evaluation and surgical treatment of a patient with an aneurysmal interatrial septum and an intracardiac thrombus traversing a patent foramen ovale. Anesth Analg 2008;106:769–70
4. Krasuski RA, Hart SA, Allen D, Qureshi A, Pettersson G, Houghtaling PL, Batizy LH, Blackstone E. Prevalence and repair of intraoperatively diagnosed patent foramen ovale and association with perioperative outcomes and long-term survival. JAMA 2009;302:290–7
5. Cabanes L, Coste J, Derumeaux G, Jeanrenaud X, Lamy C, Zuber M, Mas JL. Interobserver and intraobserver variability in detection of patent foramen ovale and atrial septal aneurysm with transesophageal echocardiography. J Am Soc Echocardiogr 2002;15:441–6
6. Tempe DK, Sharma S, Banerjee A, Sharma V, Ramamurthy P, Datt V. The utility of transesophageal echocardiography for detecting residual shunt in a patient undergoing atrial septal defect repair. Anesth Analg 2007;104:777–8
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APPENDIX: VIDEO CAPTIONS

Video 1. Midesophageal 4-chamber view shows bifid atrial septal aneurysm protruding into the right atrium. LA = left atrium.

Video 2. Three-dimensional (3D) transesophageal echocardiography (TEE) images using “live zoom” mode show the bifid atrial septal aneurysm with a median raphe from the left atrial aspect.

Video 3. Two-dimensional (2D) transesophageal echocardiography (TEE) shows no shunting during performance of Valsalva maneuver across the atrial septal aneurysm. After Valsalva is off, after a brief transition, left-to-right shunting becomes visible.

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Clinician's Key Teaching Points By Kent H. Rehfeldt, MD, Martin Stechert, MD, and Martin J. London MD
  • An atrial septal aneurysm is characterized by redundant tissue around the fossa ovalis that undergoes exagerated motion during the cardiac cycle. Diagnostic criteria include total excursion of the redundant tissue of at least 15 mm or a deviation of at least 10 mm from midline. Atrial septal aneurysm is often associated with other atrial septal defects, including patent foramen ovale (present in 60% of these patients), secundum atrial septal defect, with the potential for interatrial shunt. Observational studies have reported an association with cryptogenic stroke.
  • Transesophageal echocardiography (TEE) is more sensitive than transthoracic echocardiography in diagnosing atrial septal aneurysm given the closer proximity of the transducer to the atrial structures. Imaging the midesophageal bicaval, 4-chamber, and right ventricular inflow-outflow views are useful in examining atrial septal pathology while M-mode imaging can be used to quantitate septal excursion. If diagnosed, interatrial shunting should excluded using color flow Doppler and or a bubble study.
  • In this case, TEE performed before aortic valve replacement revealed the presence of an atrial septal aneurysm with a unique bi-lobed appearance which was better characterized using 3 dimensional (D) imaging given its complex structure. This is a previously unreported variant of uncertain significance. A patent foramen ovale was also present.
  • Although atrial septal aneurysm is usually easily diagnosed using routine 2D imaging, growing use of 3D imaging is likely to better reveal previously unrecognized variants of this and other cardiac abnormalities which may be lead to better appreciation of the potential for clinical pathology.

Supplemental Digital Content

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© 2011 International Anesthesia Research Society