The Variability of Cardiac Output Estimations Made with the High-Frequency Undamped Balistocardiograph

Abstract

Recordings of the ballistocardiogram were made on successive days in a group of subjects free from clinical signs of heart disease. The effects of ambulation and meals on the recordings were evaluated. A small but measurable increase in cardiac index following meals was observed. Significant individual differences were found. In order to obtain comparable ballistocardiographic records, it is important for the patient to fast for four to five hours preceding the measurements. However, familiarity with the procedure and prior bed rest are not essential. Only one set of calculations by one observer is required.