Asociación de la variabilidad de la frecuencia cardiaca y de la variabilidad de áreas pupilares en sujetos sanos, con respiración controlada.

There are a variety of protocols to probe the autonomic nervous system (ANS). A non invasive tool to asses this activity is by studying the heart rate variability (HRV), under controlled maneuvers. Controlled respiration induces modulation in tachograms (time intervals between cardiac beats) the so-called respiratory rythms. In the pupil some authors have also reported these respiratory changes, but they are less evident than in the heart rate and have been poorly studied. In this work we registered the spontaneous HRV and pupillary area variability (PAV) simultaneously. This system simultaneously register the EKG in D2 and the pupil activity (at three frames per second) under conditions of controlled luminance, in eight normal subjects with an age range 23-35 years, with a maneuver of controlled respiration at a rate of six respirations per minute for two minutes to study the relationship between the HRV and PAV. In this maneuver, the tachogram and pupillogram signals were analized in the frequency domain at the same frequency criteria than HRV, by mean periodogram, also we calculated its coherence function. The spectral analysis showed an evident band centered in 0.1 Hz in both spectrum, this band is correspondent to respiratory rhythm. This is most evident in the coherence function and it has a signifcat value of 0.7 (significance ≥ 0.5). That shows the close relation between both signals in this maneuver; it probably reflects a common origin of respiratory modulation at this different ANS effectors. During inspiration the pupil dilates whereas during expiration the pupil constricts showing the same type of alternation sympathetic/parasympathetic observed at the heart level. [ABSTRACT FROM AUTHOR]