Analysis of interval measurements on CSE multilead reference ECGs

As part of the International Electrotechnical Commission's (IEC) efforts to develop standards for interpretive electrocardiographs, electrocardiograms (ECGs) of the Common Standards of Electrocardiography (CSE) multilead measurement database were processed to (1) determine whether original ECG data would offer any advantage over cycle-repeated (artificial) ECGs and (2) compare the "clean" ECGs selected for interval measurement compliance testing (n = 100) with the remaining 25 "noisy" or nonsinus rhythm ECGs. Two sets of CSE measurement ECGs, namely, 125 original ECGs of the MO1 series and 125 artificial ECGs of the MA1 series were divided into 100 IEC-selected clean ECGs with good P and T waves and 25 noisy or nonsinus ECGs and processed for global wave duration and interval measurements (P duration, PR interval, QRS duration, and QT interval). The measured duration and interval values were compared against the CSE reference values (medians of referee values for 25 physician overread ECGs and medians of interpretive programs for the rest) to compute the measurement "differences". Also, the data of the median cardiac complex were evaluated for noise content. The original ECG data gave consistently smaller differences for all of the four measurements than the differences with the artificial ECG data. The noise levels in the median complexes formed from the original ECG data were significantly lower than the noise levels in the median complexes from the artificial ECG data. The noise levels in the medians of the 100 clean ECGs were lower than the noise levels in the medians of the 25 noisy ECGs for both the original and artificial ECG data.