[Cardiac mass screening of school children at Ichikawashi, Chiba Prefecture].
D002648:Child; D002675:Child, Preschool; D004562:Electrocardiography; D006331:Heart Diseases / Q000097:blood / Q000175:diagnosis*; D006801:Humans; D007564:Japan; D008403:Mass Screening; D010701:Phonocardiography