The substantial pressure exerted on the heart by the gas trapped in the mediastinum with subsequent impairment of central venous return and obstruction of diastolic filling may lead to a flattening of the cardiac silhouette resembling the oblate-spheroid morphology of the earth itself (which like many planets assumes this shape due to a combination of rotational and gravitational forces), i.e. the earth-heart sign 1.
- 1. Carillo G, Caballero G, Carretero M. The Lancet. 2014;383 (9915): . doi:10.1016/S0140-6736(13)62634-3