title: A long-term observation of the electrocardiographic changes in aged and old people.
mesh_terms: D000368:Aged; D000375:Aging; D004562:Electrocardiography; D005260:Female; D005500:Follow-Up Studies; D006321:Heart / Q000502:physiology*; D006801:Humans; D008297:Male; D008875:Middle Aged; D012737:Sex Factors