title: The normal ECG and its variations.
mesh_terms: D000367:Age Factors; D001827:Body Height; D001835:Body Weight; D004562:Electrocardiography; D005260:Female; D006321:Heart / Q000502:physiology*; D006801:Humans; D008297:Male; D011247:Pregnancy; D044469:Racial Groups; D012737:Sex Factors; D013909:Thorax; D013997:Time Factors