Validation of a Polar® human heart rate monitor for measuring heart rate and heart rate variability in adult dogs under stationary conditions

Heart rate variability (HRV) is considered to be a measure of autonomic regulation of cardiac activity for assessing stress and welfare in animals. Polar® human heart rate monitors are frequently used in animal studies to measure HRV and have been validated for this use in cows, pigs, and horses. Although Polar® monitors have been used in canine research to measure cardiac activity, we know of no studies that have tested its validity in dogs. Our objectives were as follows: (1) to collect interbeat interval (IBI) data while simultaneously using a Polar® heart rate monitor and an electrocardiogram (ECG) monitor in awake healthy dogs under stationary conditions; (2) to compare Polar® data with ECG data and examine whether any errors occurred in the Polar® data; and (3) to assess the validity of these Polar® data for recording time- and frequency-domain HRV data in dogs. IBI data from the Polar® RS800CX monitor and a telemetric ECG monitor, the Televet 100, were recorded simultaneously for 5 continuous minutes in 10 adult beagles. The Polar® data were compared with the ECG data to identify possible interbeat anomalies, such as those previously identified in pigs and horses. Statistical comparisons for a variety of time and frequency domain parameters (i.e., mean heart rate [ms], mean IBI [ms], R-R max [ms], R-R min [ms], standard deviation, total variance [ms2], and root mean square of successive differences) were performed. Time and frequency domain parameters from the Polar® data were not significantly different from ECG data. The mean heart rate from the Polar® data was 123.98 bpm (range: 101.57-138.35 bpm) and from ECG data was 123.33 bpm (range: 101.57-135.08 bpm). Bland–Altman analysis was used to measure the level of agreement between the 2 data sets. The mean difference between ECG and Polar® data was 0.42 ms (limits of agreement: −126.76 to 127.60 ms); more than 95% of the differences fell between these limits. We conclude that the Polar® RS800CX digital R-R heart rate monitor is a promising instrument to reliably measure HRV in dogs under stationary conditions.