title: The mechanics of left ventricular filling during the strain phase of the valsalva maneuver in healthy subjects.
abstract: BACKGROUND
  The aim of this study was to investigate the mechanical changes in left ventricular filling during the strain phase of the Valsalva maneuver in healthy subjects.
  
  
  METHODS
  Thirty healthy volunteers were recruited to undertake the Valsalva maneuver at a load of 40 mm Hg for 10 seconds. Parameters of left ventricle filling were determined by echocardiography at baseline and at the first and second beats during the strain phase.
  
  
  RESULTS
  Compared with baseline values, the E, E/A ratio, E/esep ratio and E/elat ratio parameters all increased at the first beat (P < 0.05). Compared with the first beat values, the E, E/A ratio, E/esep ratio and E/elat ratio parameters all decreased at the second beat (P < 0.05). The results demonstrate that left ventricular filling decreases at the second beat during the strain phase of the Valsalva maneuver. Positive intrathoracic pressure decreases left-side heart and pulmonary vessel transmural pressure while increasing blood vessel resistance, which explains the decrease in left ventricular filling.
  
  
  CONCLUSIONS
  The results provide a new understanding of the underlying mechanical mechanism of the Valsalva maneuver, indicating that it should be performed clinically at a lower load and shorter strain time to avoid adverse events.
authors.affiliation: Department of Ultrasound Diagnostics, Tangdu Hospital, Fourth Military Medical University, Xi'an, China.
authors.forename: Xiao-Yong
authors.initials: XY
authors.lastname: Zhang
authors.forename: Tie-Sheng
authors.initials: TS
authors.lastname: Cao
authors.forename: Li-Jun
authors.initials: LJ
authors.lastname: Yuan
mesh_terms: D000328:Adult; D000368:Aged; D004452:Echocardiography; D005260:Female; D006339:Heart Rate; D006801:Humans; D008297:Male; D008875:Middle Aged; D014636:Valsalva Maneuver / Q000502:physiology*; D016277:Ventricular Function, Left; D055815:Young Adult