Download Giant Right Atrium: A Rare Form of Congenital Heart Disease

MARCH 2013
ISSUE 54
Giant Right Atrium: A Rare Form of Congenital Heart Disease
Ali D. Karaosmanoglu,MD; Ami B. Bhatt, MD; Sanjeev A. Francis, MD; and David E. Sosnovik, MD
Clinical History
A 54-year-old male presented with a presumed diagnosis of Ebstein’s
anomaly and atrial fibrillation. His past medical history was remarkable
due to an exploratory cardiac surgery in his childhood for a suspected
cardiac mass, which revealed an enlarged right atrium. A recent
comprehensive echocardiogram revealed a severely enlarged right
atrium with no obvious finding that would suggest Ebstein’s anomaly.
He was referred for a cardiac magnetic resonance imaging (MRI) for
further evaluation of cardiac anatomy and function.
Findings
The right ventricle and left heart chambers were displaced laterally and
posteriorly by the enlarged right atrium (Figure 1A,B). The location and
orientation of the tricuspid valve in relation to the mitral valve were
normal with no evidence of apical displacement or tethering to suggest
Ebstein’s anomaly. There was tricuspid annular dilatation and a
resulting eccentric jet of tricuspid regurgitation seen on phase contrast
images (Figure 2A,B).
Figure 1A
Figure 1B
Figure 2A
Figure 2B
Discussion
Idiopathic dilatation of the right atrium is a very rare condition of
unknown origin and was first reported by Bailey. The partial loss of
atrial muscle fibers with progressive atrial enlargement was proposed
as the causative mechanism. The clinical presentation varies but is
frequently an incidental finding detected on the chest radiography done
for routine evaluation or during the evaluation of the atrial fibrillation.
Approximately 50% of the patients are asymptomatic at the time of the
diagnosis. The common presenting symptoms, when they occur, are
shortness of breath (28%), palpitations (17%) and arrhythmia (12%).
Echocardiography, computed tomography (CT) and MRI can all provide
important structural and functional information about this condition. MRI
can provide high-resolution images of the right atrium and right ventricle
as well as quantitative right ventricular volume and systolic function.
In addition, alternative pathologies can be excluded. The differential
diagnoses of this rare entity include Ebstein’s anomaly, Uhl’s anomaly,
cardiac tumor, pericardial effusion or pericardial cyst. In our patient, a
clinical diagnosis of Ebstein’s anomaly was first considered before the
results of echocardiography and MRI were obtained. Surgical reduction
of the right atrium can be considered in symptomatic patients although
the optimal treatment of this rare condition is not well established.
Figure 1(A,B): Multiplanar (A) Four chamber steady-state free
precession (SSFP) image demonstrates a markedly enlarged
right atrium with displacement of the right ventricle and left heart
chambers. Note the normal relation of the mitral (black arrow) and
tricuspid valves (white arrow). (B) Short axis SSFP image again
demonstrates the markedly enlarged right atrium. RA: Right atrium,
RV: Right ventricle, LA: Left atrium, LV: Left ventricle.
Figure 2(A,B): Phase contrast imaging demonstrates an eccentric,
anteriorly directed jet of tricuspid regurgitation (arrow) in both the
magnitude (A) and phase contrast images (B).
REFERENCES
1. Bailey CP. Surgery of the heart. Philadelphia: Lea & Febiger Publisher; 1955. P. 413
2. Gomes S, Wolfenden H, Lambros J. Giant right atrium in an adult: case report of a rare condition. Heart Lung Circ 2012;21:50-52
3. Kroft LJ, de Roos. A MRI diagnosis of giant right atrium. Am J Roentgenol , 2007;189:94-95
Editors:
Suhny Abbara, MD, MGH Department of Radiology
Sanjeev A. Francis, MD, MGH Division of Cardiology