Cor triatriatum masked by coexisting COPD in an adult.

Cor triatriatum presenting in adulthood is extremely rare. We describe a case of adult cor triatriatum in which the diagnosis was initially masked by the concomitant existence of COPD. Cardiac catheterization revealed only slightly elevated pulmonary wedge pressure despite severe pulmonary arterial hypertension. Both the primary lung disease and cor triatriatum greatly accentuated the pulmonary vascular disease which led to a reduction of pulmonary blood flow. Consequently, pulmonary venous obstruction was masked and was not reflected by measuring pulmonary wedge pressure. The diagnosis was made by two-dimensional echocardiography and left ventriculography.