Atrial distension in humans during microgravity induced by parabolic flights

Abstract

Videbaek, Regitze, and Peter Norsk. Atrial distension in humans during microgravity induced by parabolic flights. J. Appl. Physiol. 83(6): 1862–1866, 1997.—The hypothesis was tested that human cardiac filling pressures increase and the left atrium is distended during 20-s periods of microgravity (μG) created by parabolic flights, compared with values of the 1-G supine position. Left atrial diameter ( n = 8, echocardiography) increased significantly during μG from 26.8 ± 1.2 to 30.4 ± 0.7 mm ( P < 0.05). Simultaneously, central venous pressure (CVP; n = 6, transducer-tipped catheter) decreased from 5.8 ± 1.5 to 4.5 ± 1.1 mmHg ( P < 0.05), and esophageal pressure (EP; n = 6) decreased from 1.5 ± 1.6 to −4.1 ± 1.7 mmHg ( P < 0.05). Thus transmural CVP (TCVP = CVP − EP; n = 4) increased during μG from 6.1 ± 3.2 to 10.4 ± 2.7 mmHg ( P < 0.05). It is concluded that short periods of μG during parabolic flights induce an increase in TCVP and left atrial diameter in humans, compared with the results obtained in the 1-G horizontal supine position, despite a decrease in CVP.