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Determination of Cardiac Size From Chest Roentgenograms Following Skylab Missions (SKYRAY)
Research Area:
Cardiovascular physiology
Species Studied
Scientific Name: Homo sapiens Species: Human

Cardiac size is a major factor in the clinical evaluation of the healthy or failing heart. Knowledge of heart size assists the interpretation of both electrocardiographic and hemodynamic information. The evaluation of changes in cardiac size has been important in the overall cardiovascular assessment of orthostatic intolerance observed among the majority of astronauts following space missions.

Decreased cardiothoracic transverse diameter ratios were reported following Mercury, Gemini, and Apollo space flights. The majority of crewmembers who exhibited postflight decreases in the cardiac silhouette size also showed a decreased orthostatic tolerance to lower body negative pressure. Similar findings were also reported by Soviet investigators following 30-day bedrest studies and in cosmonauts upon return from space missions. This paper presents further radiological data from all three Skylab manned missions and discusses the physiological factors possibly involved in the cardiac silhouette changes.

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Nicogossian AE, Hoffler GW, Johnson RL, Gowen RJ. Chapter 39: Determination of Cardiac Size from Chest Roentgenograms Following Skylab Missions. In: Johnson RS and Dietlein LF, editors. Biomedical Results from Skylab. Washington DC: NASA, 1977: 400-405. NASA SP-377. [NTRS]

Nicogossian AE, Hoffler GW, Johnson RL, Gowen RJ. Determination of Cardiac Size Following Space Missions: The Second Manned Skylab Mission. Presented at the Annual Aerospace Medical Meeting, Washington, D.C., May 1974.

Cardiac volume
Cardiovascular deconditioning

Data Information
Data Availability
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Cardiac area (product of long and short diagonal diameters)
Cardiac silhouette area (planimetry)
Cardiothoracic area ratio (C/T<sub>A</sub>)
Cardiothoracic transverse diameter ratio (C/T<sub>D</sub>)

Mission/Study Information
Mission Launch/Start Date Landing/End Date Duration
Skylab 2 05/25/1973 06/22/1973 28 days
Skylab 3 07/28/1973 09/25/1973 59.5 days
Skylab 4 11/16/1973 02/08/1974 84 days

Additional Information
Managing NASA Center
Johnson Space Center (JSC)
Responsible NASA Representative
Johnson Space Center LSDA Office
Project Manager: Pamela A. Bieri
Institutional Support
National Aeronautics and Space Administration (NASA)
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