|Marchant Forde, Ruth - DEMONTFORT UNIVERSITY, UK|
|Marlin, D - ANIMAL HEALTH TRUST, UK|
Submitted to: American Society of Animal Science Proceedings
Publication Type: Abstract Only
Publication Acceptance Date: April 2, 2003
Publication Date: June 22, 2003
Citation: MARCHANT FORDE, R.M., MARLIN, D.J., MARCHANT FORDE, J.N. VALIDATION OF A 24H POLAR RR RECORDER FOR MEASURING HEART RATE VARIABILITY IN PIGS. AMERICAN SOCIETY OF ANIMAL SCIENCE PROCEEDINGS. 2003. Technical Abstract: Measures of heart rate variability (HRV) can yield important information about the functioning of the autonomic nervous system, and are potentially powerful tools in the assessment of animal well-being. The equipment necessary for data collection has been difficult to obtain and use, but recently an ambulatory monitor designed to collect 24h of data has been developed but not validated for use in animals. Our objectives were to measure the accuracy of the Polar RR Recorder using gold standard ECG and to examine and categorise occurring anomalies and to ascertain their impact on the outcome of HRV analysis. Five one-year-old gilts were socially isolated from their pen mates and cardiac activity was simultaneously measured using 2 systems, a Polar RR Recorder and a telemetric ECG system, for 20 min. The Polar data was manually assessed both against and in isolation of the ECG data to identify anomalous beats, which were then assigned to one of 5 identified error categories. The anomalies in the Polar data were corrected and statistical comparisons were performed between the 3 data sets to evaluate the effects of anomalies on HRV analysis. Bland-Altman analysis was used to measure the level of agreement between the ECG, uncorrected Polar, and corrected Polar data. No anomalies or ectopies were found in the ECG data but 46 (0.81% of total interbeat intervals [IBIs]) were located in the Polar uncorrected data. Manual identification and editing procedures reduced this error to 0.018%. Mean heart rate and IBI parameters were unaffected by error (P>0.05). SD and RMSSD were 45 and 50% higher when anomalies were present in the data (P<0.001). The mean difference between the ECG and uncorrected Polar data was 1.36ms (limits of agreement -69.03 to 71.74ms). This was greatly improved to 0.36ms (limits of agreement -5.37 to 6.10ms) after editing. Overall, just a small proportion of error can bias the outcome of HRV analysis. This bias is greatly reduced by correcting the anomalous beats. Bland-Altman analysis demonstrated that when there is error present in the Polar data it cannot be used interchangeably with the ECG data. However, if there are no anomalies present or if anomalies are classified and corrected then the 2 systems can be used interchangeably.