A new method for long-term monitoring of the ballistocardiogram, heart rate, and respiration.

The principle of the static charge-sensitive-bed (SCSB) method is described. The method is simple and inexpensive. From the SCSB recording the ballistocardiogram (BCG) and respiratory movement can be simultaneously recorded by selective filtering of the original signal. The SCSB recording thus enables continuous long-term monitoring of the BCG, heart rate, respiratory rate, respiratory amplitude, and body movements. There are no electrodes or cables connected to the subject. The SCSB-BCG signal was studied by comparing the SCSB method with the conventional ultralow-frequency (ULF) acceleration BCG. The wave forms at rest and the amplitude responses to physical exercise were studied by both methods. Multiple recordings of the BCG, heart rate, respiratory movement, respiratory rate, and body movements after exercise and during sleep using the SCSB method are presented. The SCSB method opens new approaches to long-term studies of the regulation of myocardial performance, heart rate, and respiration. Applications of the SCSB method for clinical sleep studies, patient monitoring and cardiovascular screening examinations are discussed.