Minimum Bandwidth Requirements for Recording of Pediatric Electrocardiograms

Abstract

Background-Previous studies that determined the frequency content of the pediatric ECG had their limitations: the study population was small or the sampling frequency used by the recording system was low. Therefore, current bandwidth recommendations for recording pediatric ECGs are not well founded. We wanted to establish minimum bandwidth requirements using a large set of pediatric ECGs recorded at a high sampling rate. Methods and Results-For 2169 children aged 1 day to 16 years, a 12-lead ECG was recorded at a sampling rate of 1200Hz. The averaged beats of each ECG were passed through digital filters with different cut off points (50 to 300 Hz in 25-Hz steps). We measured the absolute errors in maximum QRS amplitude for each simulated bandwidth and determined the percentage of records with an error Ͼ25 V. We found that in any lead, a bandwidth of 250 Hz yields amplitude errors Ͻ25 V in Ͼ95% of the children Ͻ1 year. For older children, a gradual decrease in ECG frequency content was demonstrated. Conclusions-We recommend a minimum bandwidth of 250 Hz to record pediatric ECGs. This bandwidth is considerably higher than the previous recommendation of 150 Hz from the American Heart Association. Key Words: electrocardiography Ⅲ pediatrics Ⅲ bandwidth F or accurate recording of ECGs, the bandwidth of the recording system is of major importance. The bandwidth, which is defined as the frequency range between low and high frequency cutoffs (Ϫ3 dB), should at least extend to the highest frequency component in the ECG signal. Many studies have been performed to determine the frequency content of the adult ECG, 1-8 but only few studies addressed the frequency content of the pediatric ECG. 9,10 Riggs et al 9 studied the frequency spectrum of the ECG of only 8 children and concluded that the vast majority of information is confined to frequencies Ͻ100 Hz. However, determining the frequency content of an ECG by inspecting its frequency spectrum is difficult. The ECG spectra appear to be monotonically decreasing, and it is hard to tell which frequency components belong to the ECG and which to noise. Moreover, this approach does not show the effect of reduced bandwidth on wave amplitudes, which from a clinical point of view is the more important information.Berson et al 10 recorded vectorcardiograms from a group of 600 infants. They filtered the waveforms with different low-pass filters and determined the amplitude differences between filtered and unfiltered waves, concluding that a bandwidth of 100 Hz is required to avoid amplitude errors Ն10%. However, the original signals were recorded at a sampling rate of 500 Hz. It has been questioned whether this rate is high enough to obtain accurate measurements in pediatric ECGs. 1,4,11 The American Heart Association (AHA) recommends 150 Hz as minimum bandwidth and 500 Hz as minimum sampling rate for recording pediatric ECGs, but these recommendations also state that it is unknown how far the bandwidth of systems has to extend due to the limitations of previous studies. 12 In the pr...

Assessment of the 12-Lead ECG as a Screening Test for Detection of Cardiovascular Disease in Healthy General Populations of Young People (12–25 Years of Age)

“…191,192 Among the most important of these is operator selection of inadequate bandwidth for the ECG. [193][194][195] In children and adolescents, inappropriate low-pass filtering (high-frequency cutoff <250 Hz) limits noise in the recorded signal but reduces the amplitude of R waves used to estimate ventricular mass, [195][196][197] whereas inappropriate high-pass filtering (low-frequency cutoff >0.05 Hz or its digital equivalent) limits baseline wandering but can introduce artifactual deviation of the J point and ST segment. 198,199 A major source of potential technical error is misplacement of the limb or precordial electrodes, not uncommonly including inadvertent lead reversals, [200][201][202][203][204][205][206] in which the V 1 and V 2 leads are placed in the second (rather than the fourth) intercostal space and the left precordial V 5 and V 6 leads are placed October 7, 2014 below the horizontal extensions of V 4 in the fifth intercostal space.…”

Recommendations for the Standardization and Interpretation of the Electrocardiogram

“…43,44 Greater bandwidth may be required for accurate determination of amplitudes in infants. 35,45,46 The European CSE group recommended that waveforms should be recognized if they have amplitudes of at least 20 V and durations of at least 6 ms. 23 This implies a high-frequency response in the range of 150 Hz. A 2001 Dutch report showed that in order to keep amplitude errors Ͻ25 V in Ͼ95% of the cases, a bandwidth up to 250 Hz is needed for pediatric cases and up to 150 Hz for adolescents.…”

“…A 2001 Dutch report showed that in order to keep amplitude errors Ͻ25 V in Ͼ95% of the cases, a bandwidth up to 250 Hz is needed for pediatric cases and up to 150 Hz for adolescents. 35 …”

“…24 The ANSI/AAMI document also details maximum allowable errors for individual determinants of overall input signal reproduction, which extend beyond the scope of the present report but are important guidelines for manufacturers. 24 These most recent limits continue to be recommended for adolescents and for adults, with extension of the high-frequency cutoff to 250 Hz in children, 35 subject to demonstration of fidelity testing by individual manufacturers according to standard methods. 23 Electrocardiographs should automatically alert the user when a suboptimal highfrequency cutoff, such as 40 Hz, is used, and a proper high-frequency cutoff should automatically be restored between routine standard ECG recordings.…”

“…The QRS of infants often contains important components as high as 250 Hz. 35 The fundamental frequency of T waves is approximately 1 to 2 Hz. 23 Filtering of the ECG signal to within the band between 1 to 30 Hz produces a stable ECG that is generally free of artifact, but this bandwidth is unacceptable for diagnostic recording because it produces distortions of both high-and low-frequency components of the signal.…”