Systemic hypertension is a common complication years after successful repair of coarctation of the aorta. The study proposes to use multi- dimensional phase velocity magnetic resonance imaging to determine whether abnormal blood flow patterns across the aortic arch and/or abnormal aortic compliance contribute to post-coarctation repair hypertension. The study population will consist of patients with: repaired coarctation normotensive at rest, repaired coarctation hypertensive at rest, and normal controls. The relationships between aortic blood flow and measured parameters will provide insight into possible mechanisms of hypertension after repair of coarctation.