Noszczyk-Nowak A
Department of Internal Disease with Clinic of Horses, Dogs and Cats, Faculty of Veterinary Medicine, University of Environmental and Life Sciences, pl. Grunwaldzki 47, 50-366 Wrocław, Poland.
Pol J Vet Sci. 2012;15(3):469-75. doi: 10.2478/v10181-012-0072-9.
Heart rate turbulence (HRT) is modulated by the baroreceptor reflex and it was suggested that it could be used as a measure of autonomic dysfunction. Impaired HRT is of a significant prognostic value in humans after myocardial infarction, suffering from dilated cardiomyopathy and patients with heart failure. So far no studies were performed assessing the importance of HRT in dogs. The aim of this study was to prospectively evaluate the HRT turbulence onset (TO) and the turbulence slope (TS) in healthy dogs and in dogs with DCM and to compare the HRT in dogs with DCM that died during the first 30 days of observation and dogs with DCM that survived the first 30 days after the HRT analysis. The current study was aimed at determining reference value of the TO and TS of HRT in healthy dogs (control group) and dogs with dilated cardiomyopathy (DCM group). The tests were carried out on 30 healthy dogs and 30 dogs with DCM composed of Boxers, Doberman pinschers and Great Danes, of different sexes and body weights from 22 to 72 kg, aged between 1.5 and 11.5 years, submitted to the 24-hour Holter monitoring. HRT parameters were calculated using an HolCard software algorithm. TO is a percentage difference between the heart rate immediately following ventricular premature complex (VPC) and the heart rate immediately preceding VPC. TS corresponds to the steepest slope of the linear regression line for each sequence of five consecutive normal intervals in the local tachogram. The average TO in healthy dogs was determined as -13.55 +/- 11.12%, TS was 21.33 +/- 9.66 ms/RR. TO in dogs with DCM was determined as - 2.61 +/- 2.1% and TS was 6.15 +/- 3.86 ms/RR. Parameters of HRT were statistically significantly decreased (p < 0.01) in dogs with DCM. HRT TO and TS were statistically significantly decreased in dogs with DCM. Dogs with DCM that survived more than 30 days of observation had HRT statistically significantly decreased in comparison to dogs with DCM that died after the 30'th day of observation. Decreased HRT parameters in dogs with DCM suggest an autonomic neuropathy which principally consists of the withdrawal of the cardiac parasympathetic tone. The more the autonomic neuropathy is advanced the faster the death of the dog with DCM might occur, with no correlation with the level of the heart failure.
心率震荡（HRT）受压力感受器反射调节，有人提出它可作为自主神经功能障碍的一项指标。HRT受损在心肌梗死后的人类、患有扩张型心肌病的患者以及心力衰竭患者中具有显著的预后价值。迄今为止，尚未进行评估HRT在犬类中重要性的研究。本研究的目的是前瞻性评估健康犬以及患有扩张型心肌病（DCM）的犬的HRT震荡起始（TO）和震荡斜率（TS），并比较在HRT分析后观察的前30天内死亡的患有DCM的犬和存活超过30天的患有DCM的犬的HRT。当前研究旨在确定健康犬（对照组）和患有扩张型心肌病的犬（DCM组）的HRT的TO和TS的参考值。对30只健康犬和30只患有DCM的犬进行了测试，这些犬包括拳师犬、杜宾犬和大丹犬，性别和体重各异，体重从22至72千克不等，年龄在1.5至11.5岁之间，均接受了24小时动态心电图监测。使用HolCard软件算法计算HRT参数。TO是室性早搏（VPC）后即刻心率与VPC前即刻心率之间的百分比差异。TS对应于局部心动过速图中五个连续正常间期序列的线性回归线的最陡斜率。健康犬的平均TO确定为-13.55±11.12%，TS为21.33±9.66毫秒/RR。患有DCM的犬的TO确定为-2.61±2.1%，TS为6.15±3.86毫秒/RR。患有DCM的犬的HRT参数在统计学上显著降低（p<0.01）。患有DCM的犬的HRT TO和TS在统计学上显著降低。在观察中存活超过30天的患有DCM的犬与在第30天之后死亡的患有DCM的犬相比，其HRT在统计学上显著降低。患有DCM的犬的HRT参数降低提示存在自主神经病变，主要表现为心脏副交感神经张力的减退。自主神经病变越严重，患有DCM的犬死亡可能越快，且与心力衰竭程度无关。
