A method for accurate localization of the first heart sound and possible applications
2008 (English)In: Physiological Measurement, ISSN 0967-3334, Vol. 29, no 3, 417-428 p.Article in journal (Refereed) Published
We have previously developed a method for localization of the first heart sound (S1) using wavelet denoising and ECG-gated peak-picking. In this study, an additional enhancement step based on cross-correlation and ECG-gated ensemble averaging (EA) is presented. The main objective of the improved method was to localize S1 with very high temporal accuracy in (pseudo-) real time. The performance of S1 detection and localization, with and without EA enhancement, was evaluated on simulated as well as experimental data. The simulation study showed that EA enhancement reduced the localization error considerably and that S1 could be accurately localized at much lower signal-to-noise ratios. The experimental data were taken from ten healthy subjects at rest and during invoked hyper- and hypotension. For this material, the number of correct S1 detections increased from 91% to 98% when using EA enhancement. Improved performance was also demonstrated when EA enhancement was used for continuous tracking of blood pressure changes and for respiration monitoring via the electromechanical activation time. These are two typical applications where accurate localization of S1 is essential for the results.
Place, publisher, year, edition, pages
Institutionen för medicinsk teknik , 2008. Vol. 29, no 3, 417-428 p.
ensemble averaging, detection, localization, heart sound, bioacoustics
Medical and Health Sciences
IdentifiersURN: urn:nbn:se:liu:diva-11856DOI: 10.1088/0967-3334/29/3/011OAI: oai:DiVA.org:liu-11856DiVA: diva2:18260
Original publication: C Ahlstrom, T Länne, P Ask and A Johansson, A method for accurate localization of the first heart sound and possible applications, 2008, Physiological Measurement, (29), 3, 417-428. http://dx.doi.org/10.1088/0967-3334/29/3/011. Copyright: Institute of Physics and IOP Publishing Limited, http://www.iop.org/EJ/journal/PM2008-05-202008-05-202009-08-17