This is a study which will serve to supplement and control project Z01-CL-02005-10 BB. Cardiac patients will be enrolled if they undergo closed mitral commissurotomy or cardiac catheterization but do not receive blood. They will then be followed prospectively for 6 months and hepatitis rates compared with patients undergoing open heart surgery. This should provide data on the relative risk of hepatitis between transfusion exposure and exposure to a hospital environment and the types of hepatitis associated with each.