IDIOPATHIC HYPERTROPHIC SUBAORTIC STENOSIS DIAGNOSED BY REFLECTED ULTRASOUND

The echocardiographic findings in 16 patients with idiopathic hypertrophic subaortic stenosis are described and compared with those in 25 patients with valvular aortic stenosis. A cluster of septal echoes of varying thickness impinging on the echoes of the anterior mitral leaflet during early diastole in 13 of 16 patients with idiopathic hypertrophic subaortic stenosis was the typical finding. A similar finding was present in only 1 patient with valvular aortic stenosis. It is suggested that this pattern indicates interference with the normal anterior mitral leaflet motion by the severe septal hypertrophy during early diastole. The pattern of decreased slope with normal configuration seen in some patients with aortic stenosis (group C) and in 3 with idiopathic hypertrophic subaortic stenosis (group B) may indicate a lesser degree of interference. The decreased left ventricular compliance present in both conditions is probably an important underlying factor. © 1969.