The number of signals in multilead ECGs in individuals

The number of independent signals in multilead electrocardiograms (ECGs) (body surface maps) of individuals have been determined by using two different methods. Both methods are based on an analysis of the eigenvalues of the spatial covariance matrix corresponding to the individual multilead ECG. One method takes only the noise level into account (threshold method). The other method is based on an information theoretic criterion (minimum description length) and uses explicitly the statistical properties of the noise (noise covariance). The analysis was performed on the QRS complexes and ST-T complexes of the multilead ECG of 61 subjects. The noise was estimated from three isoelectric intervals (PQ interval). For the different subjects, 0–14 signals (with a mean of 7 signals) were detected in the QRS interval and 0–9 signals (with a mean of 3 signals) were detected in the ST-T interval.