PRINCIPAL INVESTIGATOR (S): Walter L. Henry, Stephen E. Epstein, James M. 



Griffith, Robert E. Goldstein, and David R. 

 Redwood 



EXPERIMENT TITLE/NUMBER : Effect of Prolonged Space Flight on Cardiac Function 



and Dimensions 



PROGRAM/MISSION : Skylab 4 



CLASSIFICATION : Human 



DISCIPLINE(S) : Cardiovascular 



OBJECTIVES : To determine the effect of prolonged spaceflight on cardiac 

 function and dimension. 



PROTOCOL : The T-scan technique was used to measure thickness of the 

 ventricular system and posterobasal left ventricular wall. Stroke volume was 

 calculated by subtracting the end-systolic volume from the end-diastolic 

 volume while ejection fraction was determined by dividing stroke volume by 

 end-diastolic volume. Measurements were performed 10 days before launch, on 

 recovery day and 1, 2, H, 11, 31 and 68 days postf light. They were made in 

 conjunction with the lower body negative pressure protocol. 



EQUIPMENT : Echocardiograph . 



RESULTS : Small but significant decreases in stroke volume occurred in two of 

 the three astronauts. No significant alteration in cardiac function occurred 

 in any astronaut. The small decreases in left ventricular end-diastolic 

 volume, stroke volume and left ventricular mass were reversible postf light 

 over a 30-day period. 



CONCLUSIONS : There was no deterioration in cardiac function. The 

 cardiovascular system adapts well to prolonged weightlessness and, therefore, 

 alterations in cardiac dimensions and function are unlikely to limit man's 

 future in space. 



PUBLICATIONS : 265, 266 



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