[Accessory mitral tissue responsible for left ventricular outflow obstruction. Reports of 7 cases]

The authors report the medico-surgical experience of Marie Lannelongue hospital of a rare condition: accessory mitral valve tissue. Seven patients aged 2 to 28 years (average: 8.7 years) had left ventricular outflow obstruction due to accessory mitral valve tissue. The diagnostic was not obvious clinically and was based on the association of echocardiographic and angiographic data. This condition was associated with another intra-cardiac malformation in 6 of the 7 patients. Surgical treatment included resection of the accessory mitral valve tissue by an aortic or combined aorto-left atrial approach, together with correction of the associated intracardiac abnormality. The postoperative results were excellent with the regression of the ventriculo-aortic pressure gradient and the physiological integrity of the mitral valve.