Estimation of central aortic forces in the ballistocardiogram under rest and exercise conditions

The ballistocardiogram (BCG) signal represents the movements of the body in response to cardiac ejection of blood. The BCG signal can change considerably under various physiological states; however, little information exists in literature describing how these forces are generated. A physical analysis is presented using a finite element model of thoracic aortic vasculature to quantify forces generated by the blood flow during the cardiac cycle. The traction at the fluid-solid interface of this deformable wall model generates a central aortic force (CAF) which appears of similar magnitude to recorded BCG forces. The increased pulse pressure in an exercise simulation caused a significant increase in CAF, which is consistent with recent BCG measurements in exercise recovery.