Mid Sweden University

The objective of the pilot study was to compare validity and reliability properties of Polar RS800CX (Polar Electro Oy, Kempele, Finland) against simultaneously recorded electrocardiogram (ECG) measuring time- and frequency-based short-term heart rate variability (HRV) parameters, in dogs during stationary standing position. Five-minute recordings with less than 5% error rates from inter-beat interval (IBI) series obtained by Polar RS800CX and ECG, in 8 adult dogs, were used for HRV analysis. Polar data were statistically compared to the ECG data to assess for systematic differences in time- and frequency-based HRV parameters. Relative and absolute reliabilities were estimated by intraclass correlation coefficient, Spearman ρ, Bland and Altman analysis, standard error of measurement, and standard error of measurements in percentage. Paired t test was used to determine the statistical significance of differences between the measurement methods. Results: There were high correlation coefficients between HRV parameters obtained from Polar RS800CX and ECG. Intraclass correlation coefficients were 0.98-1.00, and Spearman ρ was 0.93-0.98. There were differences between the methods in 2 HRV parameters, the standard deviation of normal-to-normal IBIs (SDNN) (P = 0.035) and the square root of the mean squared differences of successive normal-to normal IBIs (RMSSD) (P = 0.034). Standard error of measurements was between 2.8-11.6% in ECG and between 2.6-11.8% in Polar, indicating rather high measurement error in 3 of the HRV parameters in both measurement methods. Close agreements and high correlation estimates in this pilot study indicated acceptable relative reliability in Polar RS800CX measuring time- and frequency-based HRV parameters in the group of dogs studied. However, the present pilot study revealed differences between Polar RS800CX and ECG in time-based standard deviation of normal-to-normal and square root of the mean squared differences of successive normal-to normal parameters, and that small amounts of erroneous IBI segments from Polar negatively impact on the validity and reliability properties of Polar RS800CX. © 2015 Elsevier Inc.