[P-wave signal averaging-ECG: normal values and reproducibility].

Signal averaging techniques are used for detection of low amplitude, high frequency signals in the surface ECG. P-wave signal-averaging has been used to predict the risk for development of atrial tachyarrhythmias in patients with structural heart disease. There is, however, a lack of prospective studies evaluating normal values of the P-wave signal-averaged ECG in healthy individuals. Moreover, day-to-day reproducibility of results of P-wave signal-averaging is not precisely known. Thus, the aim of this study was to determine normal values and reproducibility of time-domain P-wave signal-averaging in a large cohort of healthy volunteers. A commercially available device (MAC 5000, Marquette Hellige) was used for signal-averaging. A vector magnitude was calculated from Frank's orthogonal leads after P-waves were sampled and filtered with a spectral filter using fast fourier transform. We examined 123 volunteers without cardiovascular disease at two occasions. Mean P-wave duration was 114 +/- 13 ms for the overall study population. There was a slight but statistically significant increase in filtered P-wave duration with age (r = 0.32, p < 0.001). All values were reliably reproducible upon the second examination (r = 0.624 to 0.706, p < 0.0001). These results may serve as a future reference to other studies examining patients with structural heart disease.