Cardiac performance is influenced by rotational changes of position in the transversal plane, both in the horizontal and in the 60̊ head-up postures.

Cardiac performance is enhanced in LLP versus SP and in HUT-LL versus HUT-LB, which can be attributed to improved venous return, conceivably, wholly or in part, due to increased hydrostatic pressure gradients between the caval veins and the heart in the LLP and HUT-LL positions.