title: Repetitive high G exposure is associated with increased occurrence of cardiac valvular regurgitation.
abstract: BACKGROUND
  Exposure to repeated high +Gz loads and the methods to prevent loss of consciousness cause unique stresses on the cardiovascular system. The purpose of this study was to determine if the +Gz environment is associated with an increased occurrence of valvular regurgitation in pilots of high performance aircraft.
  
  
  METHODS
  There were 247 subjects who were divided into pilot (n = 46) and non-pilot (n = 201) groups. Pilots were defined as those individuals who had flown at least 1000 h in high performance aircraft. The echocardiographic data of these subjects were examined retrospectively.
  
  
  RESULTS
  We found a statistically significant association between pulmonic insufficiency and exposure to high +Gz stress in pilots vs. non-pilots (chi2 = 13.09, p = 0.0002). In addition, there was a greater incidence of tricuspid regurgitation (chi2 = 4.97, p = 0.025) and concurrent pulmonic insufficiency and tricuspid regurgitation (chi2 = 14.1, p = 0.0002) in the pilot group.
  
  
  CONCLUSIONS
  There is a direct relationship between repetitive exposure to a +Gz environment and pulmonic insufficiency, tricuspid regurgitation, or concurrent pulmonic insufficiency and tricuspid regurgitation. This may be secondary to the transient increase in right ventricular pressure due to acceleration forces or straining maneuvers utilized to prevent or postpone +Gz induced loss of consciousness (G-LOC).
authors.affiliation: Wyle Laboratories, Houston, TX, USA.
authors.forename: D S
authors.initials: DS
authors.lastname: Martin
authors.forename: D S
authors.initials: DS
authors.lastname: D'Aunno
authors.forename: M L
authors.initials: ML
authors.lastname: Wood
authors.forename: D A
authors.initials: DA
authors.lastname: South
mesh_terms: D000328:Adult; D000337:Aerospace Medicine; D005260:Female; D006801:Humans; D018471:Hypergravity / Q000009:adverse effects*; D015994:Incidence; D008297:Male; D009784:Occupational Diseases / Q000000981:diagnostic imaging / Q000209:etiology* / Q000503:physiopathology; D016273:Occupational Exposure / Q000009:adverse effects*; D015995:Prevalence; D011665:Pulmonary Valve Insufficiency / Q000000981:diagnostic imaging / Q000209:etiology* / Q000503:physiopathology; D012189:Retrospective Studies; D012307:Risk Factors; D012720:Severity of Illness Index; D014262:Tricuspid Valve Insufficiency / Q000000981:diagnostic imaging / Q000209:etiology* / Q000503:physiopathology; D014463:Ultrasonography; D014474:Unconsciousness / Q000517:prevention & control; D014636:Valsalva Maneuver; D017725:Ventricular Pressure; D018544:Weightlessness Countermeasures