PRINCIPAL INVESTIGATOR(S): Lawrence F. Dietlein, and Carlos Vallbona 



EXPERIMENT TITLE/NUMBER : Inflight Phone-cardiogram, M004 



PROGRAM/MISSION : Gemini 4, 5 



CLASSIFICATION : Human 



DISCIPLINE(S) : Cardiovascular 



OBJECTIVES : To measure and correlate the various phases of electrical and 

 mechanical activity of the cardiac cycle in order to gain insight into the 

 cardiac functional status of crewmembers during prolonged spaceflight. 



PROTOCOL : An electrocardiogram and phonocardiogram of each crewmember were 

 recorded throughout the mission. Recording occurred in two periods. The 

 initial period was continuous for 9 minutes,, starting at 1 minute before 

 liftoff until orbital insertion. The final period was continuous from 5 

 minutes before reentry until splashdown. Also, 1 minute records were made at 

 hourly intervals, for the first 24 hours and at 4 hour intervals for the 

 remainder of the mission until 5 minutes before reentry. 



EQUIPMENT : Phonocardiographic transducer, an electrocardiographic signal 

 transducer and onboard biomedical tape recorder. 



RESULTS : Inflight rare premature atrial and ventricular contractions were 

 found. Fluctuations of electromechanical systole duration correlated with 

 heart rate. There were stable values for electromechanical delay. Peak heart 

 rates occurred during launch and reentry. They were lower and stable inflight. 

 The postf light rate was 18-62% higher than pref light. 



CONCLUSIONS : Wide fluctuations in the duration of cardiac cycle were noted 

 throughout the missions. Fluctuations in the duration of electromechanical 

 systole that correlated with changes in heart rate and stable values for 

 electromechanical delay were observed. There was evidence of adrenergic 

 reaction at lift-off, during entry, and in the few hours that preceded entry. 



PUBLICATIONS : 82, 158, 159, 162, 166, 167, 168, 460, 532 



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