The effect of internal DC shocks on the atrial fibrillation frequency

J Diaz, N Castro, OJ Escalona, JMCC Anderson, BM Glover, JA Adgey

Research output: Chapter in Book/Report/Conference proceedingConference contribution

Abstract

The objective of this study, was to investigate the effect of internal DC shocks on the atrial fibrillation frequency (AFF). AFF has previously been shown to predict the success and energy requirements in patients undergoing internal cardioversion (IC) of atrial fibrillation (AF). However the possibility that unsuccessful shocks during IC may influence the AFT has not been before studied. Thirty eight patients with AF, suggested for DC cardioversion at the Royal Victoria Hospital in Belfast, were included in our study. Two catheters were positioned in the right atrial appendage (RAA) and the coronary sinus (CS), to deliver a biphasic shock waveform, synchronized with the R wave of the electrocardiogram (ECG) signal. A voltage step-up protocol (50-300 V) was used for patient cardioversion. The ECG was analyzed for a mean of 52,8+/-10.1 seconds (corresponding to segments before and after nonsuccessful. shocks). Atrial fibrillatory activity was extracted by means of bandpass filtering and ventricular activity (QRST) cancellation. QRST complexes were cancelled using a recursive least squared (RLS) adaptive filter. FFT was applied to the residual atrial fibrillatory signal. AFF was estimated from the dominant frequency within the 3-12 Hz band of the power spectrum. R-R intervals during the segments were also analyzed. A total of 26 patients were successfully cardioverted, employing 167 shocks (141 nonsuccessful). AFF, computed with 10 s of signal, showed significant reduction (mean 0.3052 +/- 1.1055 Hz, P=-0.028) comparing segments immediately before and after shocks, and AFF significantly increases (mean 0.2582 +/- 0.609 Hz, P=0.007) between segments immediately after shocks and those 35 s after. AFT showed distinct behavior according to the energy level of the shocks. In conclusion, intracardiac electric shocks could cause transitory changes in the AFF of patients with atrial fibrillation.
Original languageEnglish
Title of host publicationUnknown Host Publication
PublisherIEEE
Pages2591-2594
Number of pages4
Publication statusPublished - 2007
Event2007 ANNUAL INTERNATIONAL CONFERENCE OF THE IEEE ENGINEERING IN MEDICINE AND BIOLOGY SOCIETY, VOLS 1-16 - Lyon, France
Duration: 1 Jan 2007 → …

Publication series

NamePROCEEDINGS OF ANNUAL INTERNATIONAL CONFERENCE OF THE IEEE ENGINEERING IN MEDICINE AND BIOLOGY SOCIETY
PublisherIEEE

Conference

Conference2007 ANNUAL INTERNATIONAL CONFERENCE OF THE IEEE ENGINEERING IN MEDICINE AND BIOLOGY SOCIETY, VOLS 1-16
Period1/01/07 → …

Keywords

  • atrial fibrillation
  • internal cardioversion
  • atrial fibrillatory frequency
  • QRS cancellation
  • ECG signal processing.

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  • Cite this

    Diaz, J., Castro, N., Escalona, OJ., Anderson, JMCC., Glover, BM., & Adgey, JA. (2007). The effect of internal DC shocks on the atrial fibrillation frequency. In Unknown Host Publication (pp. 2591-2594). (PROCEEDINGS OF ANNUAL INTERNATIONAL CONFERENCE OF THE IEEE ENGINEERING IN MEDICINE AND BIOLOGY SOCIETY). IEEE. http://uir.ulster.ac.uk/6013/1/Paper_IEEE-EMBS_2007_Proc.pdf