title: Towards assessing the sympathovagal balance.
abstract: Exact assessment of the autonomic nervous system's (ANS) activity by means of heart rate variability (HRV) is a long-standing challenge. Although many techniques have been proposed to take up the challenge, none ever proposed a rationale for the approach behind the technique or a satisfying discrimination of the two activities which underlie the autonomic control of HRV. We here propose a new method, providing both an understanding of the discrimination's nature and a framework which we believe leads to a thorough assessment of the sympathovagal balance, as a trajectory between points in a well-chosen space. The methodology assumes tools from scale invariance/covariance physics. The sympathovagal balance is obtained on a beat-to-beat basis with the dynamics portrayed through a trajectory. Furthermore, universal trajectories are sought which would comprehensively describe the effect of atropine and isoproterenol injections on systems underlying the heart pace variations. Non-invasive assessment of the respective activities of the sympathetic and parasympathetic subsystems of the ANS would be possible through cardiac autonomic measurements.
authors.affiliation: Cardiovascular Department, Hôpital de la Tour Meyrin, Geneva, Switzerland.
authors.forename: Melvyn J
authors.initials: MJ
authors.lastname: Lafitte
authors.forename: Orin R
authors.initials: OR
authors.lastname: Sauvageot
authors.forename: Marion
authors.initials: M
authors.lastname: Fevre-Genoulaz
authors.forename: Marc
authors.initials: M
authors.lastname: Zimmermann
mesh_terms: D001285:Atropine / Q000008:administration & dosage; D001341:Autonomic Nervous System / Q000502:physiology*; D001696:Biomechanical Phenomena; D005260:Female; D006339:Heart Rate / Q000187:drug effects / Q000502:physiology*; D006801:Humans; D007267:Injections; D007545:Isoproterenol / Q000008:administration & dosage; D008297:Male; D008433:Mathematics; D008875:Middle Aged; D008954:Models, Biological; D008991:Monitoring, Physiologic / Q000379:methods; D013564:Sympathetic Nervous System / Q000502:physiology; D014630:Vagus Nerve / Q000502:physiology
chemical_list: D001285:Atropine; D007545:Isoproterenol