Home » 2009 » Number 09-17: Characterization of a left atrial anomaly with CMR

Number 09-17: Characterization of a left atrial anomaly with CMR

Case from: Katherine A, Williams, MSIV and Robert C. Gilkeson, MD
University Hospitals Case Medical Center, Cleveland, OH

Clinical history: A 67-year-old female with hypertension presented with a 5-month history of exertional chest pain and dyspnea. Physical exam identified a grade II/VI systolic ejection murmur. Transthoracic echocardiography showed normal LV size and function (EF 60%) and a linear echodensity was noted in the LA cavity of uncertain etiology. Cardiac MRI was performed to further characterize this structure.

 

Figure 1

Figure 2

CMR Findings: Axial HASTE (Figure 1) and true-FISP images (Figure 2) show a well-defined soft tissue web extending from the superior roof of the left atrium. Axial true-FISP cine image (Movie 1) demonstrates the freely mobile nature of the left atrial soft tissue membrane.  Coronal phase contrast cine images (Movie 2) re-demonstrate that the membrane is freely mobile and does not cause obstruction of flow from the left atrium to the mitral valve.

Movie 1

Movie 2

The location and appearance of this membrane is consistent with the diagnosis of cor triatriatum.

ASD and anomomalous venous return (the most common associated anomalies)(ref 1) were excluded.

Perspective: CMR is very useful for imaging cor triatriatum. It may be missed on transesophageal echocardiography due to lack of spatial resolution in the posterior left atrium close to the transducer. CMR can help to distinguish cor triatriatum from mitral stenosis (ref 2), dilatation of the coronary sinus associated with anomalous pulmonary venous return or persistent left SVC, and supravalvular mitral ring. The latter can be distinguished from cor triatriatum by the location of the diaphragm (in cor triatriatum is upstream from the LA appendage) (ref 3).

When presenting in the elderly, cor triatriatum can be associated with increased risk of atrial fibrillation and LA clots (ref 4).
In the absence of AF, LA thrombus, PV dilatation, cor triatriatum is an incidental finding and it does not require treatment. However, in the presence of symptoms or AF, surgical correction may be considered.

References

1. Alphonso N, Norgaard MA, Newcomb A, d'Udekem Y, Brizard CP, Cochrane A. Cor triatriatum: presentation, diagnosis and long term surgical results. Ann Thorac Surg 2005;80:1666-71.

2. Slight RD, Nzemi OC, Sivaprakasam R, Mankad PS. Cor triatriatum sinister presenting in the adult as mitral stenosis. Heart 2003;89:e26.

3. Jacobs A, Wienert LC, Goonewardena S, Gomberg-Maitland M, Lang R. J Am Soc Echocardiography 2006;19:468e1-4.

4. Raggi P, Vasavada BC, Parente T, Prasada S, Sacchi TJ. Uncommon etiologies of atrial fibrillation. Clin Cardiol 1996;19:513-6.

5. Modi KA et al. Diagnosis and surgical correction of cor triatriatum in an adult: combined use of transesophageal and contrast echocardiography, and a review of literature. Echocardiography. 2006;23:506-9.

6. Ibrahim T, Schreiber K, Dennig K, et al. Images in cardiovascular medicine. Assessment of cor triatriatum sinistrum by magnetic resonance imaging. Circulation. 2003;108:e107. 

7. Mychaskiw G, Sachdev V, Braden DA, Heath BJ. Supramitral ring: an unusual cause of congenital mitral stenosis. Case series and review. J Cardiovasc Surg (Torino). 2002;43:199-202.

8. Sakamoto I et al. Cine-magnetic resonance imaging of cor triatriatum. Chest. 1994;106:1586-1589.

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• Sat, 05 Mar 2011 21:23
  
  Did you attempt to measure flow velocities through the defect? Was the patient referred for surgical repair?...
• Mon, 07 Feb 2011 10:45
  
  Very interesting case.
  
  A further reason to surgically treat cor triatriatum has just recently been published:
  
  Int J Cardiol. 2010 May 14. [Epub ahead of print]
  Severe right heart failure and pulmonary hypertension because of cor triatriatum sinister in a 54year-old patient.
  Ilhan E, Ergelen M, Soylu O, Tosu R, Güvenç TS, Kul S, Tezel T....