Heart rate variability in tracheal collapse dogs treated by acupuncture

Abstract

Heart rate variability had been used to assess the autonomic nervous system in dogs. Decreased heart rate variability (HRV) has been used as indicator for abnormalities in many diseases. Malondialdehyde (MDA) is an end product of the lipid peroxidation and cellular damage. It had been used as a marker for oxidative stress. Several previous studies demonstrated that alteration in MDA level could lead to an alteration of HRV. Recently, there was no study about HRV and MDA in tracheal collapse (TC) dogs. This research evaluated the effect of acupuncture (AC) on HRV and MDA in TC dogs. Twenty TC dogs were recruited. All TC dogs were clinically evaluated based on history taking, physical examination, blood collection, and thoracic radiograph. The study was divided into two pcriods. The first period was five wecks of standard medical trcatment for TC. The second period was five weeks of AC combined with standard medical treatments. There was one week washout period between the first and the second periods. All dogs were started with the first period and followed by the second period. Before the beginning of each period, all dogs were withhold from all medical treatment at least one week. A Holter monitoring system was used to record the autonomic functions of heart at baseline before the beginning of the study, third week, and fifth week of each period after the treatment in both periods. Blood was collected at baseline and fifth week after treatments. The clinical signs of TC was evaluated using questionaires by owner interview at fifth week of both peroids. In the second period of the study, data of a six-minute walk test (6MWT) was collected before the initiation of the study and after the fifth week. At the end of the experiment, HRV, MDA level, the clinical signs from questionnaires, and HR during 6MWT were analyzed. In the time-domain analysis of HRV including mean NN, SDNN, SDANN, ASDNN, RMSSD, and pNN50. The standard medical treatment of the first period demonstrated that only RMSSD was impaired in fifth week compared to that of the third week (p<0.05). However, time-domain parameters (mean NN, SDNN, RMSSD, and pNN50) in AC with the standard medical treated group were improved since third week compared to that of the baseline (p<0.05). In addition, the frequency-domain of HRV including VLF, LF, HF, TP, and LF/HF ratio demonstrated that LF/HF ratio in AC combined with the standard medical treatment of the second period was improved since week three compared to that of the baseline (p<0.05). The serum MDA level in AC combined with the standard medical treatment of the second period was decreased at week five compared to that of the baseline (p<0.05), while there was no alteration in serum MDA level in the standard medical treatment of the first period. Based on questionnaire, severity of clinical signs and HR after the six-minute walk test were decreased at fifth weck after AC combined with the standard medical treatments when compared to that of the baseline (p<0.05). According to the results mentioned above, this study concluded that AC combined with standard medical treatment could improve the clinical signs and HRV, while reduced serum MDA level and HR during the 6MWT in TC dogs.