Thirty-three adult patients with systemic lupus erythematosus (SLE) were studied to determine whether there was an association between subclinical abnormalities of left ventricular function, conduction defects, and the presence of antibodies to Ro and/or La. Twelve patients had one or both of these antibodies. Conduction defects were present in 2, neither being currently positive for Ro or La antibody. There was no difference in abnormalities of left ventricular function between those with or without antibody. Valvular abnormalities were present in 11, 6 of whom had focal or diffuse thickening of one or more valves. Adults with SLE and anti-Ro and/or La antibody do not appear to be at particular risk of conduction defects. Subclinical left ventricular functional abnormalities were not associated with the presence of these antibodies.