In this study, children and young adults with Marfan's syndrome were randomly assigned to receive atenolol or losartan and were followed for 3 years. There was no significant difference between the two groups in the rate of aortic-root dilatation. Marfan's syndrome is an autosomal dominant disorder of connective tissue affecting approximately 1 in 5000 people. 1 Cardiovascular disease, mainly progressive aortic-root dilatation and dissection, is the leading cause of death in Marfan's syndrome. After an open-label, randomized trial comparing propranolol with no therapy, published in 1994, showed a reduced rate of aortic enlargement among treated patients, beta-adrenergic receptor antagonists (beta-blockers) became the mainstay of medical management. 2 Current management includes serial cardiac imaging, exercise restriction, administration of beta-blockers, and elective aortic-root replacement. 3 Although early diagnosis and refined medical and surgical treatment have improved survival, patients with Marfan's syndrome continue to have . . .