A method for noninvasive beat‐by‐beat visualization of His bundle signals

• Published in: Annals of noninvasive electrocardiology 2023-09, Vol.28 (5), p.e13076-n/a
• Main Authors: Sengottuvel, S., Shenbaga Devi, S., Sasikala, M., Satheesh, S., Selvaraj, R. J.
• Format: Article
• Language: English
• Subjects: Body measurements; Cardiac arrhythmia; EKG; Electrophysiological recording; Heart; His bundle; His bundle signals; HV interval; interval‐dependent wavelet thresholding; Magnetic fields; Magnetocardiography; Original; Sensors; Signal averaging; signal space projection; Signal to noise ratio; Time series
• ISSN: 1082-720X; 1542-474X
• DOI: 10.1111/anec.13076

Background Invasive recording of His bundle signals (HBS) in electrophysiological study (EPS) is important in determining HV interval, the time taken to activate the ventricles from the His bundle. Noninvasive surface measurements of HBS are attempted by averaging typically 100–200 cardiac cycles of ECG time series in body surface potential mapping (BSPM) and in magnetocardiography (MCG) which records weak cardiac magnetic fields by highly sensitive detectors. However, noninvasive beat‐by‐beat extraction of HBS is challenged by ramp‐like atrial signals and noise in PR segment of the cardiac cycle. Methods By making use of a signal‐averaged trace showing prominent HBS as a guide trace, we developed a method combining interval‐dependent wavelet thresholding (IDWT) and signal space projection (SSP) technique to eliminate artifacts from single beats. The method was applied on MCG recorded on 21 subjects with known HV intervals based on EPS and noninvasive signal‐averaging, including five subjects with BSPM recorded subsequently. The method was also applied on stress‐MCG of a subject featuring autonomic dynamics. Results HBS could be extracted from 19 out of 21 subjects by signal‐averaging whose timing differed from EPS between −8 and 11 ms as tested by 2 observers. HBS in single beats were seen as aligned patterns in inter‐beat contours and were appreciable in stress‐MCG and conspicuous than BSPM. The performance of the method was evaluated on simulated and measured MCG to be adequate if the signal‐to‐noise ratio was at least 20 dB. Conclusions These results suggest the use of this method for noninvasive assessments on HBS. A novel method to unravel beat‐by‐beat surface recordings of His bundle signals is proposed. The method has been successfully demonstrated on 19 subjects for whom the invasive electrophysiological study had already been performed. This is inclusive of five subjects with BSPM measurements. The method has been qualitatively and quantitatively compared and these results persuade to use it for noninvasive assessments.