Since the VCG is not only influenced by the activity of the heart but also by the movements of the client and his respiration, preprocessing by filtering is required. Furthermore an appropriate location for the measurement of the VCG has to be found. A measure of reliability based on the correlation function of the VCG leads to a useful point of measurement which can be found not only on the thorax close to the heart.
The analysis of the characteristica of the ECG like the heart beat is the basis for a medical diagnosis. The same has to be done with the VCG. One of the goals of the analysis is to detect atrial fibrillation. Whereas the heart beat covers normally the range of 50 to 100 beats per minute in the case of atrial fibrillation the beat might be 300 beats per minute or more. It is shown in this paper that the measure of reliability might not only be used to find the optimal location to measure the VCG but also for the detection of atrial fibrillation.
This method has been derived on the basis of data from clients in a hospital with different heart deseases. The investigations are going on because the new method has not yet reached the level required for clinical application.