Relationship between Ballistocardiographic Forces and Certain Events in the Cardiac Cycle

The temporal relationships of the various waves of the ballistocardiogram have been studied by means of simultaneously recorded electrocardiograms, femoral pulses, and electrokymograms of the great vessels and heart chambers. A modification of the Dock type of electromagnetic, undamped, direct ballistocardiograph has been employed in this study of 23 normal individuals. The total duration of mechanical systole in the great vessels has been found to correspond closely to the H-L interval. The HIJKL complex of the ballistocardiogram appears to be entirely related to the events of ventricular systole. The M, N and O waves represent after-waves occurring during diastole.