Respiratory Induced Modulation in f-Wave Characteristics During Atrial Fibrillation

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The autonomic nervous system (ANS) is an important factor in cardiac arrhythmia, and information about ANS activity during atrial fibrillation (AF) may contribute to personalized treatment. In this study we aim to quantify respiratory modulation in the f-wave frequency trend from resting ECG. First, an f-wave signal is extracted from the ECG by QRST cancelation. Second, an f-wave model is fitted to the f-wave signal to obtain a high resolution f-wave frequency trend and an index for signal quality control ((Formula presented.)). Third, respiratory modulation in the f-wave frequency trend is extracted by applying a narrow band-pass filter. The center frequency of the band-pass filter is determined by the respiration rate. Respiration rate is estimated from a surrogate respiration signal, obtained from the ECG using homomorphic filtering. Peak conditioned spectral averaging, where spectra of sufficient quality from different leads are averaged, is employed to obtain a robust estimate of the respiration rate. The envelope of the filtered f-wave frequency trend is used to quantify the magnitude of respiratory induced f-wave frequency modulation. The proposed methodology is evaluated using simulated f-wave signals obtained using a sinusoidal harmonic model. Results from simulated signals show that the magnitude of the respiratory modulation is accurately estimated, quantified by an error below 0.01 Hz, if the signal quality is sufficient ((Formula presented.)). The proposed method was applied to analyze ECG data from eight pacemaker patients with permanent AF recorded at baseline, during controlled respiration, and during controlled respiration after injection of atropine, respectively. The magnitude of the respiratory induce f-wave frequency modulation was 0.15 ± 0.01, 0.18 ± 0.02, and 0.17 ± 0.03 Hz during baseline, controlled respiration, and post-atropine, respectively. Our results suggest that parasympathetic regulation affects the magnitude of respiratory induced f-wave frequency modulation.

Original languageEnglish
Article number653492
JournalFrontiers in Physiology
Publication statusPublished - 2021

Bibliographical note

Funding Information:
Funding. This work was supported by the European Union's Horizon 2020 research and innovation programme under the Marie Sklodowska-Curie grant agreement No. 766082, the Swedish Research Council (grant VR2019-04272), and the Crafoord Foundation (grant 20200605).

Publisher Copyright:
© Copyright © 2021 Abdollahpur, Holmqvist, Platonov and Sandberg.

Copyright 2021 Elsevier B.V., All rights reserved.

Subject classification (UKÄ)

  • Cardiac and Cardiovascular Systems

Free keywords

  • atrial fibrillation
  • autonomic nervous system
  • ECG processing
  • f-wave frequency
  • parasympathetic regulation
  • respiratory modulation


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