Psuedo-Cor Triatriatum in an Elderly Patient With Dyspnea of Exertion: An Undescribed Condition Characterized by 3-Dimensional Transesophageal Echocardiography.

A 66-year-old gentleman with no prior cardiac history presented with dyspnea on exertion and chest pain for 1 month. His workup included a transthoracic echocardiogram, which demonstrated findings suggestive of cor triatriatum (C-TAT) with uncertain degree of hemodynamic obstruction. In addition, mild left ventricular systolic dysfunction and segmental wall motion abnormalities suggestive of coronary artery disease were noted. The patient then underwent transesophageal echocardiography (TEE) to define better the structural characteristics and hemodynamic significance of the C-TAT, left and right heart catheterization to assess pressure gradients between the upper and lower left atrial chambers by simultaneous measurement of pulmonary capillary wedge and left ventricular end-diastolic pressures, and coronary angiography. Multiplane 2-dimensional TEE demonstrated an atrial membrane extending from the inferior portion of the interatrial septum to the superior aspect of the lateral atrial wall. This membrane exhibited a medial large oval opening with bidirectional flow and a ≤2 mm Hg gradient. Three-dimensional TEE imaging re-demonstrated this obliquely oriented membrane; however, of most importance, it revealed that the membrane divided the atria into a medial funnel and C-shaped cavity with a large distal oval shape opening and an even larger lateral atrial cavity. These findings were inconsistent with a true C-TAT and rather demonstrated what we defined as a pseudo-C-TAT membrane. Simultaneous right and left heart catheterization confirmed a minimal gradient of 3 to 5 mm Hg and coronary angiography demonstrated severe 3-vessel coronary disease as the primary cause of the patient's clinical syndrome.