title: Thoracoscopic sympathectomy increases efferent cardiac vagal activity and baroreceptor sensitivity.
abstract: OBJECTIVE
  Thoracoscopic sympathectomy at levels T2 or T2-T3 is a treatment for focal hyperhidrosis and facial blushing. These levels of the sympathetic trunk innervate the heart, and consequently, the procedure is reported to change the heart rate variability due to changes in efferent cardiac autonomic activity. Our objective was to investigate the effects of thoracoscopic sympathectomy on global autonomic control, including baroreceptor sensitivity.
  
  
  METHODS
  Eight patients (6 F, median age 28 years [range 20-58 years]) were exposed to the tilt-table test and cardiopulmonary exercise test before, and 3 months after, thoracoscopic sympathectomy. Eight healthy age-, gender- and BMI-matched controls were used as controls and underwent the same tests once. During tilt-table testing electrocardiogram, blood pressure, impedance cardiography and respiration were measured continuously, and efferent cardiac autonomic balance was estimated.
  
  
  RESULTS
  The heart rate measured during orthostatic stress test was lowered after thoracoscopic sympathectomy (between-group; P = 0.01) due to a change in autonomic tone, with increased vagal (high-frequency power n.u.; P = 0.001), and reduced sympathetic efferent cardiac activity (low-frequency power n.u.; P < 0.001). Baroreceptor sensitivity measured during rest was increased (26 ± 13 vs 44 ± 19 ms/mmHg; P = 0.01), and diastolic blood pressure reduced after surgery (P = 0.01). The increases in systolic blood pressure and the sympathetic marker CCV-LF in response to orthostatic stress were higher before sympathectomy, with almost no increases post-surgically (condition × group interaction; P = 0.01 and P = 0.001, respectively). We found no change in post-procedure exercise capacity, although patients had a lower peak VO2 and maximal cardiac index than controls.
  
  
  CONCLUSIONS
  Thoracoscopic sympathectomy changes the autonomic tone towards increased vagal activity; this is potentially cardioprotective. To our knowledge, this is the first study to show increased baroreceptor sensitivity after thoracoscopic sympathectomy.
authors.affiliation: Department of Cardiothoracic and Vascular Surgery, Aarhus University Hospital, Skejby, Denmark.
authors.forename: Elisabeth
authors.initials: E
authors.lastname: Bygstad
authors.forename: Astrid J
authors.initials: AJ
authors.lastname: Terkelsen
authors.forename: Hans K
authors.initials: HK
authors.lastname: Pilegaard
authors.forename: John
authors.initials: J
authors.lastname: Hansen
authors.forename: Henning
authors.initials: H
authors.lastname: Mølgaard
authors.forename: Vibeke E
authors.initials: VE
authors.lastname: Hjortdal
mesh_terms: D000328:Adult; D000704:Analysis of Variance; D001794:Blood Pressure / Q000502:physiology*; D001821:Blushing / Q000502:physiology; D016022:Case-Control Studies; D005080:Exercise Test; D005260:Female; D006339:Heart Rate / Q000502:physiology*; D006801:Humans; D006945:Hyperhidrosis / Q000601:surgery; D008297:Male; D008875:Middle Aged; D011311:Pressoreceptors; D013562:Sympathectomy / Q000379:methods*; D013906:Thoracoscopy / Q000379:methods*; D018667:Tilt-Table Test; D014630:Vagus Nerve / Q000601:surgery
keywords: Hyperhidrosis; Sympathectomy; Thoracoscopy