title: A novel low-complexity post-processing algorithm for precise QRS localization.
abstract: Precise localization of QRS complexes is an essential step in the analysis of small transient changes in instant heart rate and before signal averaging in QRS morphological analysis. Most localization algorithms reported in literature are either not robust to artifacts, depend on the sampling rate of the ECG recordings or are too computationally expensive for real-time applications, especially in low-power embedded devices. This paper proposes a localization algorithm based on the intersection of tangents fitted to the slopes of R waves detected by any QRS detector. Despite having a lower complexity, this algorithm achieves comparable trigger jitter to more complex localization methods without requiring the data to first be upsampled. It also achieves high localization precision regardless of which QRS detector is used as input. It is robust to clipping artifacts and to noise, achieving an average localization error below 2 ms and a trigger jitter below 1 ms on recordings where no additional artifacts were added, and below 8 ms for recordings where the signal was severely degraded. Finally, it increases the accuracy of template-based false positive rejection, allowing nearly all mock false positives added to a set of QRS detections to be removed at the cost of a very small decrease in sensitivity. The localization algorithm proposed is particularly well-suited for implementation in embedded, low-power devices for real-time applications.
authors.affiliation: Department of Electrical Engineering, Eindhoven, University of Technology, Postbus 513, 5600 MB Eindhoven, The Netherlands ; Philips Research, High Tech Campus 34, 5656 AE Eindhoven, The Netherlands.
authors.forename: Pedro
authors.initials: P
authors.lastname: Fonseca
authors.affiliation: Department of Electrical Engineering, Eindhoven, University of Technology, Postbus 513, 5600 MB Eindhoven, The Netherlands ; Philips Research, High Tech Campus 34, 5656 AE Eindhoven, The Netherlands.
authors.forename: Ronald M
authors.initials: RM
authors.lastname: Aarts
authors.affiliation: Philips Chair for Medical Information Technology, RWTH Aachen University, Pauwelsstraße 20, D-52074 Aachen, Germany.
authors.forename: Jérôme
authors.initials: J
authors.lastname: Foussier
authors.affiliation: Department of Electrical Engineering, Eindhoven, University of Technology, Postbus 513, 5600 MB Eindhoven, The Netherlands ; Philips Research, High Tech Campus 34, 5656 AE Eindhoven, The Netherlands.
authors.forename: Xi
authors.initials: X
authors.lastname: Long
keywords: Electrocardiography; Motion artifacts; QRS localization; Trigger jitter