Retrospective study of allometric relationship between heart rate, electrocardiographic parameters and bodyweight in dogs

ABSTRACT The allometric relationship between bodyweight (BW) and heart rate (HR) has been described as inversely proportional in domestic species, but that has been refuted. The relationship between HR and electrocardiographic variables is described in literature. However, studies about the variation and influence of factors on the hemodynamic and electrocardiographic parameters in dogs are not abundant. As the metabolic rate is defined as the production and dissipation of heat by the body surface area (BSA) in m², it is essential to define that relationship. A retrospective study was conducted to analyze the correlation between HR, ECG parameters and BW in dogs. One thousand electrocardiographic tracings were analyzed in addition to the ECG parameters and clinical data such as gender, age and bodyweight. The determination of BSA was performed as follows: BSA (m2) = (10.1 x bodyweight 0.67) X 10-4. When the unified groups were analyzed, there was a negative but weak correlation (r= -0.14, P< 0.0001) between bodyweight and HR. There were differences between weight groups regarding electrocardiographic variables. There is no allometric relationship between BW and HR in dogs. Weight was associated with changes in ECG variables.

摘要：家养动物中体重（bodyweight, BW）与心率（heart rate, HR）的异速生长关系曾被描述为负相关，但该结论已被推翻。现有文献已对心率与心电图（electrocardiography, ECG）参数间的关联进行了阐述，但针对犬类血流动力学及心电图参数的影响因素与变异规律的研究尚不多见。由于代谢率被定义为体表面积（body surface area, BSA，单位为平方米）所对应的机体产热与散热水平，明确二者间的关联至关重要。本研究通过回顾性分析，探究犬类心率、心电图参数与体重间的相关性。研究共分析了1000份心电图描记图，并收集了心电图参数及性别、年龄、体重等临床数据。体表面积的测算方法如下：BSA（m²）= (10.1 × 体重^0.67) × 10^-4。对合并后的全部研究对象进行分析时，体重与心率呈弱负相关（r=-0.14, P<0.0001）。不同体重分组的心电图参数存在显著差异。本研究结果表明，犬类体重与心率间不存在异速生长关系，且体重与心电图参数的变化存在相关性。