In most cases of subaortic stenosis there is associated hypertrophic muscular stenosis. Classical surgical treatment by transaortic ventriculomyotomy can be assessed by bidigital septal examination through a complementary pulmonary arteriotomy as reported in this paper. Preoperative and postoperative trans-stenotic subaortic pressure gradients were measured in 5 patients with a mean decrease of about 85 mmHg. Bidigital assessment of the residual septal thickness is likely to improve the results of transaortic ventriculomyotomy.