Gallo Júnior L, Morelo Filho J, Maciel B C, Marin Neto J A, Martins L E, Lima Filho E C
Department of Medicine, School of Medicine of Ribeirão Preto, University of São Paulo, Brazil.
Cardiovasc Res. 1987 Dec;21(12):922-7. doi: 10.1093/cvr/21.12.922.
Ten normal subjects and 14 patients with chronic Chagas' disease (seven with and seven without heart disease) underwent dynamic exercise on a cycle ergometer. Heart rate (HR), pulmonary ventilation (V), oxygen consumption (VO2), carbon dioxide production (VCO2), and respiratory quotient (RQ) were measured. Increasing workloads (25, 50, 100, and 150 W) were applied for 4 min and intercalated with resting periods. The main objective of this protocol was to analyse heart rate response in relation to the other cardiorespiratory variables in order to evaluate the functional conditions of the sympathetic and parasympathetic cardiac efferents. Analysis of the results showed that (a) the group of chagasic patients with heart disease had lower heart rates (p less than 0.05) than normal subjects during the initial 10 s (delta HR 0-10 s) of effort (fast component); (b) the difference between the normal subjects and chagasic patients without heart disease was not statistically significant; (c) the abnormalities in heart rate response were due to depression of parasympathetic efferent action on the sinus node; (d) the slow heart rate response (delta HR 1-4 min), which expresses the degree of sympathetic stimulation of the sinus node, was comparable in the three groups studied, thus showing unimpaired adrenergic responses during dynamic exercise in Chagas' disease; and (e) the V, VO2, VCO2, and RQ values were normal at all workloads in each group, suggesting that vagal dysfunction does not affect oxygen transport at these submaximal levels of dynamic exercise.
10名正常受试者和14名慢性恰加斯病患者（7名有心脏病，7名无心脏病）在自行车测力计上进行动态运动。测量心率（HR）、肺通气量（V）、耗氧量（VO₂）、二氧化碳生成量（VCO₂）和呼吸商（RQ）。增加工作量（25、50、100和150瓦），持续4分钟，并穿插休息时间。该方案的主要目的是分析心率与其他心肺变量的关系，以评估交感神经和副交感神经心脏传出纤维的功能状态。结果分析表明：（a）在运动初始10秒（ΔHR 0 - 10秒，快速成分），患有心脏病的恰加斯病患者组心率低于正常受试者（p < 0.05）；（b）正常受试者与无心脏病的恰加斯病患者之间的差异无统计学意义；（c）心率反应异常是由于副交感神经对窦房结的传出作用受到抑制；（d）表示窦房结交感神经刺激程度的缓慢心率反应（ΔHR 1 - 4分钟）在三组研究对象中相当，因此表明恰加斯病患者在动态运动期间肾上腺素能反应未受损；（e）每组在所有工作量下的V、VO₂、VCO₂和RQ值均正常，表明迷走神经功能障碍在这些次最大动态运动水平下不影响氧运输。
