Accessory mitral valve tissue causing severe subaortic stenosis with dextrocardia in a premature newborn

We report an unusual case of left-ventricular outflow obstruction caused by accessory mitral valve tissue associated with dextrocardia and ventricular septal defect in a seven-day-old, 2200 grams premature infant, who was ref erred with a heart murmur. The diagnosis was made by two-dimensional and Do ppler echocardiography which demonstrated the accessory tissue as well as a 100 mmHg peak systolic gradient between the left ventricle and the aorta. Ten days after the presentation the infant underwent emergency surgery afte r respiratory arrest and recurrent episodes of syncope. The accessory mitra l valve tissue and its fibrous extension were excised and the ventricular s eptal defect was closed. We believe that surgical treatment of patients wit h accessory mitral valve tissue should be performed early because of the po ssibility of acute deterioration. Combined aortotomy and interatrial approa ch is very helpful in evaluating the anatomy and the mitral valve function as well as delineating the tissue to be excised.