title: Observations on the incidence and mechanism of sinus arrhythmia in man at rest.
mesh_terms: D000293:Adolescent; D000328:Adult; D000367:Age Factors; D000368:Aged; D001146:Arrhythmia, Sinus / Q000453:epidemiology* / Q000503:physiopathology; D001794:Blood Pressure; D002648:Child; D002675:Child, Preschool; D006339:Heart Rate; D006801:Humans; D008297:Male; D008875:Middle Aged; D012119:Respiration