Echocardiographic evaluation of female centrifuge subjects for chronic changes in cardiac function.
BACKGROUND
High sustained G exposure as experienced in flying high performance aircraft can affect cardiac function. Numerous studies, mostly on male pilots, have evaluated the chronic effects of exposure to high G. To date, none of these studies has revealed significant positive findings in cardiac function as a result of long-term high G exposure.


METHODS
A longitudinal study was conducted on six female centrifuge panel members who did not have a history of significant high +Gz exposure. Baseline echocardiographic studies were conducted prior to any +Gz exposure on the Dynamic Environment Simulator (DES) centrifuge. The echocardiograms were repeated after each panel member completed approximately 100 3-min high G (up to 9 G) exposures over the period of 7 mo. These follow-up echos were performed after all six subjects had been exposed to at least 6 h (cumulative) of sustained acceleration > 3 G. The women were protected with the COMBAT EDGE positive pressure breathing G protection ensemble. Each subject served as her own control. All studies were evaluated independently by a cardiologist who was blinded to the order in which the echos were performed. Although complete echocardiographic studies were performed, only the parameters identified as significant in prior studies were evaluated.


RESULTS
No significant differences were found between the initial and follow-up echo parameters.


CONCLUSIONS
We found no significant differences in cardiac function after at least 6 and up to 17 h (cumulative) of exposure to G > 3 in women. These subjects will be monitored during a longitudinal study throughout their centrifuge subject career.
Albery
W B
WB
Air Force Research Laboratory, Wright-Patterson AFB, OH 45433-7901, USA.
D000337:Aerospace Medicine; D002498:Centrifugation / Q000009:adverse effects*; D004452:Echocardiography; D005260:Female; D005676:Gravity Suits; D006321:Heart / Q000502:physiology*; D006439:Hemodynamics; D006801:Humans; D018471:Hypergravity / Q000009:adverse effects*; D008137:Longitudinal Studies; D008889:Military Personnel; D011175:Positive-Pressure Respiration; D012727:Sex Characteristics; D016037:Single-Blind Method; D013997:Time Factors; D014481:United States