Discrete fibromembranous aortic stenosis in middle age. Natural history and case report.

Discrete fibromembranous subaortic stenosis may be severe at birth, progress in severity irrespective of the initial degree of obstruction, and morphologically change during the course of its natural history. Initial status, progression of the lesion and perhaps later development of fibromuscular (tunnel) and/or asymmetric septal hypertrophy may all contribute to a shortened life span and account for the different incidence of fibromembranous subaortic stenosis in children and adults. In the case reported here, a patient survived into the sixth decade with a discrete fibromembranous subaortic stenosis, which led to typical as well as unusual echocardiographic findings.