Abstract
Cor triatriatum is a rare congenital heart malformation with different
natural history which depends on the size of the aperture in the
partition between the proximal and distal chambers. In classic cor
triatriatum all pulmonary veins return to proximal chamber (accessory
left atrium, aLA), but this case we reported with left upper pulmonary
vein returned to distal chamber (true left atrium, tLA). The partition
had one 5mm aperture that allowed this patient grown up to adulthood
without any symptoms, but finally resorted to hospital with symptomatic
atrial flutter and detected this cor triatriatum accidentally. Atrial
flutter may be a long-term complication of cor triatriatum during its
natural history, surgical correction of cor triatriatum and
radiofrequency ablation for atrial flutter is recommended once
diagnosed.