|Lay Jr, Donald|
Submitted to: International Society of Applied Ethology
Publication Type: Abstract Only
Publication Acceptance Date: 3/15/2008
Publication Date: 8/5/2008
Citation: Janczak, A.M., Marchant-Forde, R.M., Marchant Forde, J.N., Hogan, D., Matthews, D.L., Dowel, C., Freeman, L.J., Lay Jr, D.C. 2008. The value of telemetry for measuring effects of snaring and saline injection on heart rate variability in pigs [abstract]. In: Boyle, L., O'Connell, N., Hanlon, A., editors. Proceedings of the 42nd International Congress of the International Society of Applied Ethology, August 5-9, 2008, Dublin, Ireland. p. 194.
Technical Abstract: We tested the quality of ECGs recorded from pigs using telemetry and intra-cardiac leads and show how pharmacological blockade influences time and frequency domain indices of HRV. A telemetric device connected to an intra-cardiac lead (DSI) was used to collect electrocardiograms (ECG) from 12, 4-month-old conventional pigs (6 barrows and 6 gilts). ECGs were collected before and after injection of saline, the muscarinergic receptor blocking agent atropine (0.1 mg/kg), the ß-adrenergic blocking agent propranolol (1.0mg/kg), or atropine and propranolol combined. The ECG recorded using this methodology was nearly completely free of noise and dropout. Samples of 512 successive inter-beat intervals were checked for errors and subjected to time and frequency domain analysis of HRV using the programs Art 4.0 and Exel. Saline injection increased heart rate (HR; Wilcoxon signed-ranks; P < 0.05 for all reported differences), reduced total power (TOT), increased the ratio of LF to HF (LF/HF) and reduced total variance of IBI’s. Compared to the change in HRV induced by saline injection (Mann Whitney U), atropine increased HR and reduced variance, but had no effect on the remaining indices of HRV. Relative to saline, propranolol increased TOT, reduced HR, and reduced LF/HF, but otherwise had no effects. Relative to saline, injection of atropine and propranolol together increased HR, decreased LF/HF, and decreased total variance, but had no effects on remaining indices of HRV. These results provide novel information regarding the validity of methodology used for collection of high quality ECGs for studying HRV in conventional pigs.