Accessory mitral valve tissue causing left ventricular outflow tract obstruction.

: Among the various causes of left ventricular outflow tract obstruction accessory mitral valve tissue is the least common. To the best of our knowledge there have been only five such cases reported to date. The aim of presenting two more cases and reviewing the literature is to bring attention to this rare anomaly as it is easy to treat provided it has been diagnosed preoperatively or recognised at surgery.