Latini Carolina Dragone, Alfonso Angélica, Filippi Maurício Gianfrancesco, Lima Mayra de Castro Ferreira, Paes Antônio Carlos, Corrêa Jaqueline Valença, Santos Beatriz Almeida, Tsunemi Miriam Harumi, Lourenço Maria Lucia Gomes
School of Veterinary Medicine and Animal Science, São Paulo State University (UNESP), Botucatu 18618-681, Brazil.
Institute of Biosciences, São Paulo State University (UNESP), Botucatu 18618-691, Brazil.
Life (Basel). 2025 Mar 18;15(3):490. doi: 10.3390/life15030490.
Canine monocytic ehrlichiosis (CME) is a globally prevalent disease transmitted by the tick and caused by the Gram-negative bacterium spp. Following an incubation period, the infection is categorized based on the progression of the disease into acute, subclinical, and chronic stages. Besides hematological alterations, the cardiovascular system is significantly impacted by the hemodynamic effects of the disease, as persistent anemia can lead to myocardial hypoxia and the activation of inflammatory processes, potentially causing myocarditis. It is known that in dogs infected with , there is a higher occurrence of arrhythmias and a predominance of sympathetic activity. This study assessed arrhythmogenic parameters, including P wave dispersion (Pd), QT dispersion (QTd), and QT instability, along with heart rate variability (HRV) analysis from 24 h Holter monitoring in naturally infected dogs during the acute phase ( = 10) and chronic phase ( = 10) compared to a control group ( = 10). The Pd and QTd values were higher in the infect group, confirming the arrhythmogenic character. Instability parameters (TI, LTI, and STI) were higher in sick animals, but no worsening was observed in the chronic phase. All HRV metrics in the time domain were higher in the control group, indicating a balanced sympathovagal activity throughout the day in healthy dogs. Additionally, parameters linked to parasympathetic activity (rMSSD and pNN50) were reduced in the sick groups, confirming the dominance of sympathetic activity. These findings indicate a decrease in HRV in sick individuals and reinforce this useful marker for assessing the influence of the autonomic nervous system on the cardiovascular system. In conclusion, CME exhibits arrhythmogenic activity characterized by the deterioration of predictive parameters for ventricular arrhythmias and increased activity of the sympathetic autonomic nervous system in the heart. This is likely secondary to myocarditis, myocardial hypoxia, and structural damage to cardiomyocytes.
犬单核细胞埃立克体病（CME）是一种由蜱传播的全球性流行疾病，由革兰氏阴性菌埃立克体属引起。经过潜伏期后，根据疾病进展，感染可分为急性、亚临床和慢性阶段。除血液学改变外，心血管系统也受到该疾病血流动力学效应的显著影响，因为持续性贫血可导致心肌缺氧和炎症过程激活，可能引发心肌炎。已知感染埃立克体的犬心律失常发生率较高，且交感神经活动占优势。本研究评估了心律失常参数，包括P波离散度（Pd）、QT离散度（QTd）和QT不稳定性，以及通过对急性期（n = 10）和慢性期（n = 10）自然感染犬进行24小时动态心电图监测分析心率变异性（HRV），并与对照组（n = 10）进行比较。感染组的Pd和QTd值较高，证实了其致心律失常特性。患病动物的不稳定性参数（TI、LTI和STI）较高，但在慢性期未观察到恶化。对照组时域中的所有HRV指标均较高，表明健康犬全天交感迷走神经活动平衡。此外，患病组与副交感神经活动相关的参数（rMSSD和pNN50）降低，证实了交感神经活动占优势。这些发现表明患病个体的HRV降低，并强化了这一用于评估自主神经系统对心血管系统影响的有用指标。总之，CME表现出致心律失常活性，其特征为室性心律失常预测参数恶化以及心脏交感自主神经系统活动增加。这可能继发于心肌炎、心肌缺氧和心肌细胞结构损伤。
