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Description
A 19-year-old woman was sent for a two-dimensional transthoracic echocardiography because of dyspnea on mild exertion of recent onset. An echocardiography revealed a membrane dividing the left atrium (LA) into a posterosuperior chamber (SC) and an anteroinferior chamber (IC) (figure 1A, video 1). However, no Doppler colour flow acceleration (figure 1B, video 2) or pressure gradient was noted. LA appendage was included in IC (figure 1C). The right heart and pulmonary artery pressure were both normal. A three-dimensional echocardiography showed the membrane in greater detail and revealed the orifice through which the blood flowed from SC to IC (video 3). Unrestrictive cor triatriatum was diagnosed and a cardiac MRI ruled out associated congenital heart defects (figure 1D). Finally, an exercise stress test was normal, so further management was expectant. Three years later, the patient remains asymptomatic.
In classic cor triatriatum, a fibromuscular diaphragm with fenestrations divides LA into SC (receiving pulmonary venous flow) and IC (true LA, containing the left atrial appendage and mitral orifice).1 The insertion of the diaphragm proximal to the left atrial appendage is the feature that distinguishes cor triatriatum from the supravalvular stenosing mitral ring.2 Age and symptoms at the time of diagnosis depend on the degree of obstruction to pulmonary venous return and associated lesions.2 However, older adults with a non-obstructive cor triatriatum may present with mitral regurgitation or atrial fibrillation.3 Treatment of asymptomatic adults is controversial and may be indicated only in those who participate in vigorous exercise, or in women considering pregnancy.2
Learning points
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Cor triatriatum in adults is an uncommon, incidental finding on an echocardiography and is usually non-restrictive.
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A membrane dividing the left atrium is seen in cor triatriatum and supravalvular mitral ring. However, the position of the membrane relative to the left atrial appendage is the distinguishing feature of the cor triatriatum.
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When the patient is asymptomatic, surgical or percutaneous intervention is reserved for those involved in vigorous athletic activities, or in women considering pregnancy.
Footnotes
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Contributors NL-R, RL and BR were equally involved in the planning, execution and reporting of the work.
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Competing interests None.
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Patient consent Obtained.
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Provenance and peer review Not commissioned; externally peer reviewed.