ALTHOUGH the availability of potent bactericidal agents has greatly reduced mortality from bacterial endocarditis,1,2 death may be caused by congestive failure, especially when infection leads to severe aortic insufficiency.3 Formation of mycotic aneurysms is a second feared complication which may lead to death even after a bacteriologic "cure."4 In the occasional patient developing endocarditis after cardiac surgery, the prognosis is less favorable because of the resistant bacterial species frequently involved and the presence of sutures or other foreign material which may become a nidus of infection.5 We have recently treated a 10-year-old girl who developed bacterial endocarditis several months after an aortic valvuloplasty for congenital deformity of the aortic valve. The uncommon organism was resistant to penicillin and her course was complicated by rupture of an intracranial mycotic aneurysm. After successful treatment of the intracranial aneurysm, replacement of her aortic valve with a ball valve prosthesis