Premium
Quantitative Comparison of Temporal and Spatial High‐Resolution Recordings of Terminal QRS
Author(s) -
YANG WEIQUN,
HORAN LEO G.,
WYLDS ANITA C.,
FLOWERS NANCY C.
Publication year - 1992
Publication title -
journal of cardiovascular electrophysiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.193
H-Index - 138
eISSN - 1540-8167
pISSN - 1045-3873
DOI - 10.1111/j.1540-8167.1992.tb01100.x
Subject(s) - beat (acoustics) , qrs complex , medicine , amplitude , root mean square , acoustics , signal averaging , cardiology , audiology , physics , telecommunications , optics , computer science , signal transfer function , quantum mechanics , transmission (telecommunications) , analog signal
Beat‐by‐Beat Recording of Terminal QRS. Introduction: Beat‐by‐beat recordings of quasiorthogonal leads were performed in 82 normal subjects (35 male and 47 female) with normal standard electrocardiograms (ECGs) in order to: (1) establish normal values for parameters that were similar to those used in signal‐averaged ECG; (2) compare these data with the signal‐averaged ECG; and (3) assess the noise level in beat‐by‐beat recording. Methods and Results: Low‐noise recordings were achieved by special instrumentation, preparation of subjects, and screening recording sites for an optimal magnetic field at 60 Hz or its harmonics without using a shielded room. Using a 40‐Hz bidirectional high‐pass filter, 95% of normal subjects had a beat‐by‐beat duration of vector magnitude complex ≤ 107 msec, a duration of low‐amplitude signal under 40 μV ≤ 37 msec, and a root mean square (RMS) voltage of last 40 msec ≥ 24.1 μV. Significant difference was found in duration of vector magnitude complex (P < 0.0001) between gender groups; this difference disappeared after normalization for height (P > 0.3). Although the beat‐by‐beat and signal‐averaged data were highly correlated in all three parameters, the beat‐by‐beat recordings exhibited a shorter duration of low‐amplitude signal (P < 0.0004) and a higher RMS voltage of last 40 msec (P < 0.002), and no significant variation in duration of vector magnitude complex (P > 0.2). The mean RMS noise in the vector magnitude lead from the normal group was 1.52 ± 0.65 μV (mean ± SD) while over 80% of the subjects had RMS noise under 1 μV in an individual lead. Conclusion: The normal values from beat‐by‐beat recordings are correlated to but different from those of signal‐averaged ECGs. Every‐beat high‐resolution recordings of terminal QRS are stable and reproducible in normal subjects. Also, the use of individual lead (s) with lower noise is recommended for better detection of low‐level terminal QRS. ( J Cardiovasc Electrophysiol, Vol. 3, pp. 109–118, April 1992 )