The aims of this study are to evaluate the efficacy of long term treatment with long acting verapamil in delaying aortic root dilation in patients with Marfan syndrome, and to evaluate the effect of treatment with verapamil and metoprolol on the elastic properties of the aorta in patients with Marfan syndrome. The information to be gained from this study may have significant clinical impact on the treatment of patients with the Marfan syndrome. Currently, there is no acceptable alternative to beta-blocker treatment for delaying the progression of aortic root dilation in afflicted patients. An alternative therapy for retardation of aortic dilatation for patients who cannot receive beta-adrenergic receptor antagonists could have a substantial impact upon their morbidity and mortality. This study may determine whether verapamil represents such an alternative.