Incidental Finding of Cor Triatriatum Sinister in an Asymptomatic Woman With Ankylosing Spondylitis

We present a 24-year-old woman with symptoms of backache, acute peripheral arthritis, joint swelling, and erythema, diagnosed with ankylosing spondylitis (AS) and determined to have cor triatriatum sinister (CTS) without cardiac symptoms. On physical examination, the patient had a rythmic S1 with a loud pulmonic component to her S2 and a grade 2/6 systolic murmur along the left sternal edge. Pulmonary examination was normal. Also her left knee and left metacarpophalangeal joints were swollen. Chest radiography revealed a slight prominence of the pulmonary arteries. Her echocardiogram showed a normal left ventricle and that the left atrium was divided into 2 distinct chambers by a membranous septum. In the left atrium, a moderately obstructive fibromuscular membrane was imaged, resulting in a transmembrane mean pressure gradient of 6 mm Hg. Pulmonary artery pressure was increased (peak systolic pulmonary pressure: 44 mm Hg). There was also mild mitral regurgitation and the atrial septum was intact. Cardiac MRI demonstrated CTS. Cardiovascular involvement is a common finding in patients with AS. Thus, careful cardiac evaluation appears to be mandatory in all cases of AS. Our case may be interesting in that to the best of our knowledge, AS with CTS has not been previously reported. Also a patient with CTS who has no cardiac symptoms is a very rare occurrence in the literature.