Changes in the Ballistocardiogram after Exercise in Normal and Abnormal Subjects

Ballistocardiograms were taken before and at intervals after mild exercise. The normal response has been ascertained by a statistical study of results obtained on 40 healthy subjects. The response of patients varies widely; in some the change after exercise is much diminished, but in others the response is abnormally increased. In some the form of the ballistocardiogram, normal at rest, becomes abnormal after exercise, so the exercise test will often bring out abnormalities not detected by observations made at rest. Additional evidence was secured that the ballistocardiogram may become abnormal before the clinical picture of coronary heart disease develops.