A rare case of an isolated aneurysmal supravalvar mitral ring in a young Nigerian adult: a cor-triatriatum mimic.

Supravalvar mitral ring is a rare congenital abnormality characterized by a ridge of connective tissue located above the mitral valve. It is a cause of congenital mitral stenosis typically presenting in childhood and usually associated with other cardiac abnormalities. We report the rare case of a 24-year-old male presenting with an isolated aneurysmal supravalvar mitral ring. He presented at the emergency room with a 2-week history of worsening heart failure symptoms and antecedent effort intolerance of 4 years duration. He was referred from a primary care facility with an echo diagnosis of cor-triatriatum. Echocardiography done at our centre revealed an isolated aneurysmal supravalvar mitral ring of the intramitral variant. This report highlights the unusual isolated presentation of a supravalvar mitral ring in a young adult and the need to carefully differentiate it from cor-triatriatum, a possible close mimic.