The Information Content of Successive RR-Interval Times in the ECG. Preliminary Results Using Factor Analysis and Frequency Analysis

Abstract

Factor analysis and frequency analysis were applied to series of interval times between successive heart beats in a preliminary effort to get a maximal amount of information from this kind of data. From a sample, with a mean heart rate ranging from 56·2 to 156·4 per minute, 25 values (partly by using thresholds) were derived and intercorrelated. Scores based on the summation of successive differences and standard-deviation scores showed a mean correlation of 0·96 and were called together a D-complex. Factor analysis revealed 4 interpretable factors, explaining 85% of the total variance. Frequency analysis results were intercorrelated with all other values and showed a high correlation with the D—complex.‘scoring ’versus ‘measuring’ is discussed.