Supravalvular aortic stenosis in the adult. A case presentation with unique associated features.

A 42-year-old symptomatic woman with possible adult Williams's syndrome (mental retardation, 'elfin facies' and supravalvular aortic stenosis (SVAS)) is documented. This patient displayed many unique features in addition to the severe SVAS (peak systolic gradient 96 mmHg): there was an associated persistent left superior vena cava draining into the coronary sinus, mitral valve prolapse (Barlow's syndrome) and complete right bundle-branch block on ECG. Peripheral pulmonary artery stenosis was absent. M-mode echocardiograhy in the adult with SVAS is described for the first time in the literature, as is the use of the 60 degrees cross-sectional scan. Both these non-invasive procedures proved of value in the diagnosis. The degree of subendocardial ischaemia, as determined by the 'endocardial viability ratio', was calculated and the possible mechanisms producing angina pectoris with 'coronary artery hypertension' in this condition are discussed. The literature on associated mitral valve abnormalities in SVAS is reviewed. A successful surgical result was obtained; the various forms of operation are outlined.