Isolated accessory mitral valve tissue in an asymptomatic elderly patient.

Accessory mitral valve tissue is a membranous or tumor-like structure observed in the left ventricular outflow tract. This congenital anomaly has been reported in more than 100 cases since 1842; however, most of them were found in patients with complex cardiac malformations. We report a 72-year-old Asian woman with isolated accessory mitral valve tissue incidentally found during the evaluation of hypertension and arrhythmia. Her left ventricular outflow tract obstruction was mild. Because worsening of the left ventricular outflow tract obstruction was reported in patients without significant obstruction at the time of diagnosis, periodical echocardiographic follow-up is necessary.