title: Origin and significance of heart rate variability.
authors.forename: Mikko
authors.initials: M
authors.lastname: Tulppo
authors.forename: Heikki V
authors.initials: HV
authors.lastname: Huikuri
mesh_terms: D002940:Circadian Rhythm / Q000502:physiology; D019411:Clinical Laboratory Techniques; D015716:Electrocardiography, Ambulatory; D006339:Heart Rate / Q000502:physiology*; D006801:Humans; D009043:Motor Activity / Q000502:physiology; D011379:Prognosis; D012146:Rest / Q000502:physiology; D013318:Stroke Volume / Q000502:physiology; D018487:Ventricular Dysfunction, Left / Q000175:diagnosis / Q000503:physiopathology