An Amplitude-Modulation Model for the QRS Complexes of Electrocardiograms

The fact that all practical QRS loops in vectorcardiograms are not geometrically well defined renders the analytical studies of QRS waveforms in electrocardiograms difficult. However, many important properties of practical loops can be revealed by and understood through the use of idealized loops which can be easily and analytically treated. By means of a uniformly inscribed circular QRS loop, one can arrive at an amplitude-modulation model for the QRS complexes of electrocardiographic leads. The possibilities of having the constituent parts of a QRS complex identified as the envelope-carrier pair or the carrier-sideband pair of an ordinary amplitude-modulated wave are revealed in this paper. This collective behavior of QRS may open up a way for the envelopes to be employed as diagnostic criteria.