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Immediate and Short‐Term Reproducibility of the P Wave Signal‐Averaged Electrocardiogram
Author(s) -
EHLERT FREDERICK A.,
ZAMAN NAJAMUZ,
STEINBERG JONATHAN S.
Publication year - 1997
Publication title -
pacing and clinical electrophysiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.686
H-Index - 101
eISSN - 1540-8159
pISSN - 0147-8389
DOI - 10.1111/j.1540-8159.1997.tb03533.x
Subject(s) - medicine , reproducibility , signal averaged electrocardiogram , cardiology , duration (music) , term (time) , electrocardiography , statistics , mathematics , art , physics , literature , quantum mechanics
While abnormalities in the P wave SAECG have been associated with the occurrence of AF, its reproducibility has never been documented. The purpose of this study was to evaluate the immediate and short‐term reproducibility of measurements from the P wave SAECG. P wave SAECGs were obtained using well‐described techniques that utilize the QHS complex as the trigger and the P wave as template for averaging. In 28 subjects (8 controls, 11 with cardiac disease, 9 with prior AF), 3 P wave SAECGs were obtained: an initial study; an immediate reacquisition; and reacquisition after 4–5 days. Vector duration and RMS voltage of the terminal 20 ms of the P wave SAECG were measured and compared. The mean P wave duration was 152 ± 14 ms on initial SAECG, 152 ± 14 ms and 152 ± 15 ms at immediate and short‐term reacquisitions, respectively (both P = NS vs initial). The mean terminal BMS voltage was 6.4 ± 6.0 mcV on initial SAECG, 6.4 ± 5.9 mcV and 6.5 ± 5.8 meV at immediate and short‐term reacquisitions, respectively (both P = NS vs initial). Linear regression analysis showed high reproducibility for both P wave duration (r = 0.94 for immediate and r = 0.96 for short‐term reacquisition vs initial) but slightly less for terminal RMS voltage (r = 0.92 for immediate and r = 0.84 for short‐term reacquisition vs initial). In subgroup analysis, P wave duration measurements were highly reproducible in controls, in subjects with cardiac disease, and in those with a history of AF. P wave duration was also reproducible for both males and females, as well as for subjects age > 65 years (r = 0.96 and 0.89 for immediate and short‐term reacquisition, respectively). Terminal RMS voltage measurements were reproducible for controls, but less reproducible in other subgroups. In conclusion, P wave duration measurements on SAEGG are reproducible when evaluated at immediate and short‐term reacquisition regardless of age, sex, cardiac disease, or prior AF. Terminal RMS voltages were less reproducible, especially in patients with cardiac disease and/or prior AF. These findings may explain conflicting observations regarding the clinical utility of terminal P wave measurements.