title: Comparison of Polar® RS800CX heart rate monitor and electrocardiogram for measuring inter-beat intervals in healthy dogs.
abstract: The aim of the present study was to assess the criterion validity, relative reliability and level of agreement of Polar® RS800CX heart rate monitor measuring inter-beat intervals (IBIs), compared to simultaneously recorded electrocardiogram (ECG) in dogs.
  
  
  METHODS
  Five continuous minutes of simultaneously recorded IBIs from Polar® RS800CX and Cardiostore ECG in 11 adult healthy dogs maintaining standing position were analyzed. Polar® data was statistically compared to ECG data to assess for systematic differences between the methods. Three different methods for handling missing IBI data were used. Criterion validities were calculated by intraclass correlation coefficients (ICCs) and corresponding 95% confidence intervals (CIs). Relative reliabilities and levels of agreement were calculated by ICCs and the Bland and Altman analysis for repeated measurements per subject.
  
  
  RESULTS
  Correlation coefficients between IBI data from ECG and Polar® RS800CX varied between 0.73 and 0.84 depending on how missing values were handled. Polar® was over- and underestimating IBI data compared to ECG. The mean difference in log transformed (base10) IBI data was 0.8%, and 93.2% of the values were within the limits of agreement. Internally excluding three subjects presenting IBI series containing more than 5% erroneous IBIs resulted in ICCs between 0.97 and 0.99. Bland and Altman analysis (n=8) showed mean difference was 1.8ms, and 98.5% of the IBI values were plotted inside limits of agreement.
  
  
  CONCLUSIONS
  This study showed that Polar® systematically biased recorded IBI series and that it was fundamental to detect measurement errors. For Polar® RS800CX heart rate monitor to be used interchangeably to ECG, by showing excellent criterion validity and reliable IBI measures in group and individual samples, only less than 5% of artifacts could be accepted.
authors.affiliation: Uppsala University, Department of Neuroscience, Uppsala, Sweden; Evidensia Djurkliniken Gefle, Gävle, Sweden. Electronic address: ann.essner@gmail.com.
authors.forename: Ann
authors.initials: A
authors.lastname: Essner
authors.affiliation: Strömsund Health Centre, Jämtland County Council, Strömsund, Sweden; Department of Health Sciences, Mid Sweden University, Östersund, Sweden.
authors.forename: Rita
authors.initials: R
authors.lastname: Sjöström
authors.affiliation: Evidensia Djurkliniken Gefle, Gävle, Sweden.
authors.forename: Erik
authors.initials: E
authors.lastname: Ahlgren
authors.affiliation: Swedish University of Agricultural Sciences, Uppsala, Sweden.
authors.forename: Pia
authors.initials: P
authors.lastname: Gustås
authors.affiliation: The Canine Fitness Centre, Calgary, Canada.
authors.forename: Laurie
authors.initials: L
authors.lastname: Edge-Hughes
authors.affiliation: Uppsala University, Department of Neuroscience, Uppsala, Sweden.
authors.forename: Lena
authors.initials: L
authors.lastname: Zetterberg
authors.affiliation: Uppsala University, Department of Neuroscience, Uppsala, Sweden.
authors.forename: Karin
authors.initials: K
authors.lastname: Hellström
mesh_terms: D000818:Animals; D004285:Dogs; D004562:Electrocardiography; D005260:Female; D006339:Heart Rate / Q000502:physiology*; D008297:Male; D008991:Monitoring, Physiologic / Q000295:instrumentation*; D015203:Reproducibility of Results
keywords: Behavior; Dogs; Heart rate variability; Physiotherapy; Reliability; Validity