title: Optimizing squatting as a physical maneuver to prevent vasovagal syncope.
abstract: OBJECTIVE
  Squatting is a potent physical maneuver to prevent syncope; however, a major drawback is that standing up from squatting is a large hemodynamic stressor that often causes new presyncopal symptoms. We tested the hypothesis that lower body skeletal muscle tensing (LBMT) attenuates the decrease of mean arterial blood pressure (MAP) upon standing from squatting when used as a maneuver to prevent vasovagal syncope.
  
  
  RESULTS
  In 18 patients (10 females and 8 males, median age 37.5 years) we followed continuous MAP, cardiac output (CO, by Modelflow) and total peripheral resistance (TPR) during tilt test-provoked pre-syncopal episodes. After standing up from squatting MAP decreased to a nadir of 64 +/- 4 mmHg (mean +/- SE), related to a reduction in CO 73 +/- 5% of supine values. Standing up with LBMT limited the reduction in CO (85 +/- 6 %, P < 0.05) and MAP nadir (to 76 +/- 3 mmHg; P < 0.05 compared to without LBMT) with fewer or no presyncopal symptoms. Standing up from squatting with and without LBMT did not affect TPR (99 +/- 5% vs. 101 +/- 7%).
  
  
  CONCLUSIONS
  LBMT is proposed as an effective follow-up maneuver to squatting when applied to prevent syncope.
authors.affiliation: Dept. of Internal Medicine, Academic Medical Center at the University of Amsterdam, F4-222 Meibergdreef 9, 1105 AZ, Amsterdam, The Netherlands. c.t.krediet@amc.uva.nl
authors.forename: C T Paul
authors.initials: CT
authors.lastname: Krediet
authors.forename: Ingeborg K
authors.initials: IK
authors.lastname: Go-Schön
authors.forename: Johannes J
authors.initials: JJ
authors.lastname: van Lieshout
authors.forename: Wouter
authors.initials: W
authors.lastname: Wieling
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D001794:Blood Pressure / Q000502:physiology*; D002302:Cardiac Output / Q000502:physiology*; D005260:Female; D006339:Heart Rate / Q000502:physiology*; D006801:Humans; D008297:Male; D008875:Middle Aged; D009068:Movement / Q000502:physiology; D018482:Muscle, Skeletal / Q000502:physiology*; D011187:Posture; D019462:Syncope, Vasovagal / Q000503:physiopathology / Q000517:prevention & control*; D018667:Tilt-Table Test