THE VERTICAL BALLISTOCARDIOGRAPH; EXPERIMENTS ON THE CHANGES IN THE CIRCULATION ON ARISING; WITH A FURTHER STUDY OF BALLISTIC THEORY

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Abstract
Theoretical studies indicated that the initial downward deflection of the ballistocardiogram was chiefly due to blood while in the heart, the largest upward deflection to blood while in the aorta. A ballistocardiograph was constructed to secure records in standing or sitting subjects. On assuming the erect posture the avg. cardiac output per min. of normal subjects remained the same. But in some subjects it regularly diminished. The state of the circulation when recumbent was an important factor in the response to arising; if above the avg. normal when recumbent the circulation usually diminished on arising; if below, it usually increased or remained the same. The drug N-methyl paredrine hydrochloride diminished the recumbent cardiac output per min. but increased it when the subject stood. An abdominal binder affected the circulation differently in the 2 positions in certain subjects. Symptoms of dizziness and light headedness when erect were not associated with a diminished cardiac output.