Physical basis of the low-frequency ballistocardiograph

Abstract

A ballistocardiograph has been constructed which is bound so weakly to the surroundings that the displacement of the center of gravity of the blood, caused by the action of the heart, can be measured.

Damping the ballistocardiograph appeared to be necessary. The influence of the binding to the surroundings and of the damping has been examined.

Records can be made by an electrocardiograph. During the recording the breath is held.

The obtained curve may be compared with others, generated by the heart action.

High-, middle-, and low-frequency ballistocardiographs have been compared theoretically.