title: Characterizing artifacts in RR stress test time series.
abstract: Electrocardiographic stress test records have a lot of artifacts. In this paper we explore a simple method to characterize the amount of artifacts present in unprocessed RR stress test time series. Four time series classes were defined: Very good lead, Good lead, Low quality lead and Useless lead. 65 ECG, 8 lead, records of stress test series were analyzed. Firstly, RR-time series were annotated by two experts. The automatic methodology is based on dividing the RR-time series in non-overlapping windows. Each window is marked as noisy whenever it exceeds an established standard deviation threshold (SDT). Series are classified according to the percentage of windows that exceeds a given value, based upon the first manual annotation. Different SDT were explored. Results show that SDT close to 20% (as a percentage of the mean) provides the best results. The coincidence between annotators classification is 70.77% whereas, the coincidence between the second annotator and the automatic method providing the best matches is larger than 63%. Leads classified as Very good leads and Good leads could be combined to improve automatic heartbeat labeling.
authors.forename: Fabian
authors.initials: F
authors.lastname: Astudillo-Salinas
authors.forename: Kenneth
authors.initials: K
authors.lastname: Palacio-Baus
authors.forename: Lizandro
authors.initials: L
authors.lastname: Solano-Quinde
authors.forename: Ruben
authors.initials: R
authors.lastname: Medina
authors.forename: Sara
authors.initials: S
authors.lastname: Wong
mesh_terms: D016477:Artifacts; D003920:Diabetes Mellitus / Q000503:physiopathology; D004562:Electrocardiography / Q000379:methods*; D005080:Exercise Test / Q000379:methods*; D006339:Heart Rate / Q000502:physiology; D006801:Humans; D012815:Signal Processing, Computer-Assisted