In humans, alterations in heart rate variability (HRV) have been associated with various forms of intracranial disease due to disturbances in the autonomic nervous system. HRV has been shown to hold prognostic value in these patients.

The aims of this study were to evaluate alterations in HRV in dogs with clinical signs of intracranial disease and the relationship of HRV with the results of brain imaging and outcome.

Ambulatory electrocardiographic recordings were prospectively obtained from 12 client-owned dogs with a history and/or neurological examination consistent with intracranial disease. Data was collected for a minimum of 12 hours the night before brain imaging (MRI or CT), while the dogs were hospitalized. Control data was gathered from 25 healthy dogs used in a parallel study on HRV. The data was analysed using Novacor Holtersoft Ultima Version 2.5.5. Time and frequency-domain measurements of HRV, Poincaré plots and their descriptors were generated from the data.

Two dogs from the diseased group were excluded, one due to the presence of persistent arrhythmia and another due to a recording time of less than 12 hours. The mean heart rate of the diseased group was higher than that of the control group when HRV parameters were calculated from 6 hours of resting data for each group. All of the measured parameters of HRV (SDNN, SDNNIDX, PNN50%, RMSSD, SD1, SD2, SD1/SD2, HF msec², LF msec²), apart from SDANN, were lower in the diseased group than the control group (p<0.03). There was no distinct Poincaré plot pattern evident for the diseased group when compared to the healthy controls. There was no significant difference in any of the HRV measurements over 12 hours of recording between dogs with intracranial lesions present on imaging (n=7) and those with no imaging abnormalities (n=3). Neither was there a significant difference between those who were alive 3 months following data collection (n=5) and those who were not (n=5).

This pilot study suggests that the presence of intracranial disease may be associated with a reduction in HRV in dogs, regardless of the underlying aetiology. HRV does not appear to be predictive of brain imaging findings in a small cohort of dogs with clinical signs of intracranial disease, and there does not appear to be a relationship between HRV and survival.

Disclosures

No disclosures to report.