Wong's anomaly - a rare variant of cor triatriatum.

Cor triatriatum sinistrum is an extremely rare congenital heart disease. It is even more uncommon in adults, and clinically significant mitral valve lesion complicating cor triatriatum is distinctly rare. Wong et al reported for the first time the rare combination of cor triatriatum sinister associated with severe mitral regurgitation and abnormal tensor apparatus of the mitral valve. We report a similar case and used the term Wong's anomaly for the syndrome, having membranous type of cor triatriatum sinistrum, severe mitral regurgitation and hypoplasia of the papillary muscles and short chordae. Color Doppler Echocardiography showed peculiar 'helmet sign' of mitral regurgitation, wherein the mitral regurgitation color jet fills the distal atrial chamber and abruptly ends in a horizontal plane as it is halted by the intra-atrial membrane.